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The study aimed to assess the local gene expression of adipokine members, namely vaspin, adiponectin, visfatin, resistin and their associated receptors - heat shock 70 protein 5 (HSPA5), adiponectin receptor 1 (AdipoR1) and adiponectin receptor 2 (AdipoR2) - in bovine follicles during the preovulatory period and early corpus luteum development. Follicles were collected before gonadotropin-releasing hormone (GnRH) treatment (0 h) and at 4, 10, 20, 25 and 60 h after GnRH application through transvaginal ovariectomy (n = 5 samples/group). Relative mRNA expression levels were quantified using real-time reverse transcription polymerase chain reaction (RT-qPCR). Vaspin exhibited high mRNA levels immediately 4 h after GnRH application, followed by a significant decrease. Adiponectin mRNA levels were elevated at 25 h after GnRH treatment. AdipoR2 exhibited late-stage upregulation, displaying increased expression at 20, 25 and 60 h following GnRH application. Visfatin showed upregulation at 20 h post-GnRH application. In conclusion, the observed changes in adipokine family members within preovulatory follicles, following experimentally induced ovulation, may constitute crucial components of the local mechanisms regulating final follicle growth and development., (© 2024 The Author(s). Reproduction in Domestic Animals published by Wiley‐VCH GmbH.)

Small dominant follicle diameter at induced ovulation, but not at spontaneous ovulation, decreased pregnancy rate, fertilization rate, and day seven embryo quality in beef cows. We hypothesized that the physiological status of the follicle at GnRH-induced ovulation has a direct effect on the transcriptome of the Cumulus-Oocyte complex, thereby affecting oocyte competence and subsequent embryo development. The objective of this study was to determine if the transcriptome of oocytes and associated cumulus cells (CC) differed among small (≤11.7 mm) and large follicles (≥12.7 mm) exposed to a GnRH-induced gonadotropin surge and follicles (11.7-14.0 mm) exposed to an endogenous gonadotropin surge (spontaneous follicles). RNA sequencing data, from pools of four oocytes or their corresponding CC, revealed 69, 94, and 83 differentially expressed gene transcripts (DEG) among oocyte pools from small versus large, small versus spontaneous, and large versus spontaneous follicle classifications, respectively. An additional 128, 98, and 80 DEG were identified among small versus large, small versus spontaneous, and large versus spontaneous follicle CC pools, respectively. The biological pathway "oxidative phosphorylation" was significantly enriched with DEG from small versus spontaneous follicle oocyte pools (FDR < 0.01); whereas the glycolytic pathway was significantly enriched with DEG from CC pools obtained from large versus small follicles (FDR < 0.01). These findings collectively suggest that altered carbohydrate metabolism within the Cumulus-Oocyte complex likely contributes to the decreased competency of oocytes from small pre-ovulatory follicles exposed to an exogenous GnRH-induced gonadotropin surge.

Threatened of extinction in Brazil, the jaguar is the largest predator in Latin America, playing an important role in the ecosystem where it is inserted. Despite of some important studies in this species, its reproductive physiology needs to be better understood for the development of more effective reproductive biotechnologies. One well studied biological aspect is the occurrence of ovulation following stimulation of the vaginal floor during copulation. This mechanical stimulation is responsible for the induction of ovulation in domestic and wild cats. Thus, the objective of the present study was to evaluate whether ovulation in captive jaguars can be induced by the above-mentioned mechanical stimulation but also by other forms of sensory stimulation. Nine jaguar (Panthera onca) females and six males were divided into three groups: Group 1 (four females), in which the females were close to the males, but with no possibility of copulation; Group 2 (three females), in which the females were in the same enclosure as the males, thereby being able to copulate; and Group 3 (two females), in which the females were completely isolated from any male of the species. Follicular growth was stimulated by administration of 800 IU of eCG, conducted three or five days before LOPU. In order to have certainty about the occurrence of ovulation, the ovaries were assessed by laparoscopy allowing the visualization of ovarian structures including follicles, recent ovulations, corpora hemorrhagica (CH) and corpora lutea (CL). Multiple CH were observed in the 2 females housed with males, as well as the two females kept in proximity of males, i.e. only visual contact (Group 1). None of the females in complete isolation from males showed CH or ovulation spots (Group 3). In summary, the seven females in contact or near proximity with males had multiple ovulations, regardless of copulation or not. Based on this evidence, we have established that jaguars are capable of two forms of induced ovulation: 1) the "mechanical" coitus-induced form that is traditional and thoroughly described for felines; 2) a "sensorial" form in which the nearby presence of a male can induce ovulation through the visual, olfactory and/or auditive senses. Further research is required for establishing the mechanisms and chemical mediators of sensorial stimulation. In addition, and consistent with expected results, we confirmed that females that received the same stimulation are incapable of ovulating when not exposed to any form of stimulation by males., Competing Interests: Declaration of competing interest None of the authors have any conflicts of interest to declare., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The ovulatory homolog model of female orgasm posits that the neuro-endocrine mechanisms underlying female orgasm evolved from and are homologous to the mechanisms mediating copulation-induced ovulation in some mammals. This model predicts that pharmacological agents that affect human orgasm, such as fluoxetine, should also affect ovulation in animals with copulation-induced ovulation, such as rabbits. We tested this prediction by treating rabbits with daily doses of fluoxetine for 2 wk and found that fluoxetine treatment reduces the number of ovulations postcopulation by 30%. In a second experiment we tested whether this result was mediated by an effect on the brain or via peripheral serotonin functions. We treated animals with fluoxetine and induced ovulation with a single injection of human chorionic gonadotropin. In this experiment ovulation rate was nominally reduced by only 8%, which is statistically not significant. We conclude that the effect of fluoxetine on copulation-induced ovulation rate supports the ovulatory homolog model of female orgasm, suggesting that female orgasm has very deep evolutionary roots among the early eutherian mammals., Competing Interests: The authors declare no conflict of interest.

Patterns of reproductive seasonality in the Carnivora are difficult to study comparatively, due to limited numbers of species for which information is available. Long-term databases of captive populations could overcome this difficulty. We apply a categorical description and a quantitative high-resolution measure (birth peak breadth, the number of days in which 80% of all births occur) based on daily observations in captivity to characterize the degree of reproductive seasonality in the Carnivora for 114 species with on average 1357 births per species. We find that the majority of species retained the birth seasonality displayed in the wild. Latitude of natural origin, delayed implantation, and induced ovulation were the main factors influencing reproductive seasonality. Most species were short-day breeders, but there was no evidence of an absolute photoperiodic signal for the timing of mating or conception. The length of the gestation period (corrected for body mass) generally decreased with birth seasonality but increased in species with delayed implantation. Birth seasons become shorter with increasing latitude of geographical origin, likely because the length of the favorable season declines with increasing latitude, exerting a strong selective pressure on fitting both the reproductive cycle and the interval offspring needs for growth following the termination of parental care into the short time window of optimal environmental conditions. Species with induced ovulation exhibit a less seasonal reproductive pattern, potentially because mates do not have to meet during a short time window of a fixed ovulation. Seasonal species of Carnivora shorten their gestation period so reproduction can occur during the short time window of optimal environmental conditions. Alternatively, other Carnivora species lengthen their gestation periods in order to bridge long winters. Interestingly, this occurs not by decelerating intrauterine growth but by delaying implantation.

The objective of the study was to compare the pituitary and ovarian responses after intramuscular, intravenous, or intrauterine administration of β-nerve growth factor (β-NGF) of seminal plasma origin (SP-NGF) in llamas. In experiment 1, mature female llamas with a growing follicle of 7 mm or greater were assigned randomly to four groups (n = 7/group) and given 2 mg of purified SP-NGF in a volume of 2 mL by (1) intramuscular administration, (2) intravenous administration, and (3) intrauterine infusion, or (4) intrauterine infusion of 2 mL of PBS (negative control). Because ovulations were not detected after intrauterine infusion in experiment 1, a second experiment was done to determine if a higher dose of SP-NGF given by intrauterine infusion, similar to a natural dose during copulation, will elicit an ovulatory response. In experiment 2, llamas with a growing follicle of 7 mm or greater were assigned randomly to three groups (n = 6/per group) given an intrauterine infusion of (1) 4 mL of raw seminal plasma, (2) 4 mL of PBS containing 20 mg of purified llama SP-NGF, or 3) 4 mL of PBS (negative control). In both experiments, the ovaries were examined daily by transrectal ultrasonography using a B-mode scanner and power Doppler mode to detect ovulation and to monitor CL growth, regression, and vascularization. Blood samples were collected to determine plasma LH and progesterone concentrations. In experiment 1, only llamas treated by intramuscular or intravenous administration of SP-NGF ovulated (7 of 7 and 6 of 7, respectively). Plasma LH concentration did not differ between the intramuscular and intravenous SP-NGF-treated groups, nor did CL diameter, CL vascularization, or plasma progesterone concentration profiles. In experiment 2, the ovulation rate was 100% for llamas treated by intrauterine infusion of raw seminal plasma or llama SP-NFG, whereas no ovulations were detected in females treated with PBS. Plasma LH concentrations did not differ between groups that ovulated, nor did CL diameter, CL vascularization, or plasma progesterone concentration profiles. We conclude that β-NGF from llama seminal plasma origin elicits a preovulatory LH surge, followed by ovulation and the development of a functional CL, regardless of the route of administration. However, the dose required to elicit pituitary and ovarian responses is higher when administered by intrauterine infusion than by intramuscular or intravenous routes., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Before pregnancy is recognized, ovulation, fertilization, and implantation must all occur. Physical activity and sedentary behavior may impact pregnancy success by altering each or all of these processes. The aim of this review was to review the association between physical activity and sedentary behavior with spontaneous female and male fertility. Method: PubMed/MEDLINE, Web of Science, CINAHL, SPORTDiscus, and Embase were searched from inception to August 9, 2021. Eligible studies included randomized controlled trials or observational studies, published in English, describing an association between physical activity or sedentary behavior (exposures) and spontaneous fertility (outcome) among women or men. Results: Thirty-four studies from 31 unique populations were included in this review (12 cross-sectional studies, 10 cohort studies, 6 case–control studies, 5 randomized controlled trials, and one case–cohort study). Of the 25 studies among women, the majority identified mixed results (n = 11) or no association (n = 9) between physical activity and female fertility. Seven studies reported on female fertility and sedentary behavior, and 2 found sedentary behavior was associated with decreased female fertility. Of the 11 studies among men, most of the studies (n = 6) found that physical activity was associated with increased male fertility. Two of the studies reported on male fertility and sedentary behavior, and neither identified an association. Conclusions: The association between spontaneous fertility and physical activity in both men and women remains unclear, and the association with sedentary behavior remains largely unexplored. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The objectives of this prospective cohort study were to characterize associations among genomic merit for fertility with ovarian and endocrine function and the estrous behavior of dairy cows during an entire nonhormonally manipulated estrous cycle. Lactating Holstein cows entering their first (n = 82) or second (n = 37) lactation had ear-notch tissue samples collected for genotyping using a commercial genomic test. Based on genomic predicted transmitting ability values for daughter pregnancy rate (gDPR), cows were classified into high (Hi-Fert; gDPR > 0.6, n = 36), medium (Med-Fert; gDPR −1.3 to 0.6, n = 45), and low fertility (Lo-Fert; gDPR < −1.3, n = 38) groups. At 33 to 39 DIM, cohorts of cows were enrolled in the Presynch-Ovsynch protocol for synchronization of ovulation and initiation of a new estrous cycle. Thereafter, the ovarian function and endocrine dynamics were monitored daily until the next ovulation by transrectal ultrasonography and concentrations of progesterone (P4), estradiol, and FSH. Estrous behavior was monitored with an ear-attached automated estrus detection system that recorded physical activity and rumination time. Overall, we observed an association between fertility group and the ovarian and hormonal phenotype of dairy cows during the estrous cycle. Cows in the Hi-Fert group had greater circulating concentrations of P4 than cows in the Lo-Fert group from d 4 to 13 after induction of ovulation and from day −3 to −1 before the onset of luteolysis. The frequency of atypical estrous cycles was 3-fold greater for cows in the Lo-Fert than the Hi-Fert group. We also observed other modest associations between genomic merit for fertility with the follicular dynamics and estrous behavior. We found several associations between milk yield and parity with ovarian, endocrine, and estrous behavior phenotypes as cows with greater milk yield and in the second lactation were more likely to have unfavorable phenotypes. These results demonstrate that differences in reproductive performance between cows of different genomic merit for fertility classified based on gDPR may be partially associated with circulating concentrations of P4, the incidence of atypical phenotypes during the estrous cycles, and, to a lesser extent, the follicular wave dynamics. The observed physiological and endocrine phenotypes might help explain part of the differences in reproductive performance between cows of superior and inferior genomic merit for fertility. [ABSTRACT FROM AUTHOR]

Background: Accurately predicting ovulation timing is critical for women undergoing natural cycle-frozen embryo transfer. However, the precise predicting of the ovulation timing remains challenging due to the lack of consensus among different clinics regarding the definition of this significant event. Objective: To compare the effectiveness of preovulatory serum progesterone levels (P4) versus luteinizing hormone levels (LH) in predicting ovulation time using two machine learning models. Methods: 771 patients who underwent autologous natural cycle-frozen embryo transfer between January 2015 and February 2022 were recruited. Utilizing variables including follicle diameters, preovulatory serum levels of LH, E2, and P4, two machine learning models were constructed to predict the ovulation time, the importance of the variables in predicting ovulation timing was further ranked. Results: Two machine learning models have the capability to accurately predict the timing of ovulation, specifically within 72, 48, or 24 h. The overall accuracy rates of the validation dataset, as determined by the classification trees and random forest models, were found to be 78.83% and 85.28% respectively. Notably, when predicting ovulation within 24 h, the accuracy rate of P4 ≥ 0.65ng/ml exceeded 92%. Furthermore, it was important to consider LH or E2 levels in conjunction with P4 when assessing ovulation timing in cases where P4<0.65ng/ml. Conclusions: Preovulatory serum P4 levels are better predictors of ovulation timing than LH levels and could be used as an alternative in clinical settings, and the model we developed can be used to pinpoint the day of ovulation. Ongoing research and advancements in technology are anticipated to enhance and refine the ovulation method. [ABSTRACT FROM AUTHOR]

Purpose: To examine the pattern of kisspeptin expression throughout the menstrual cycle in polycystic ovary syndrome (PCOS) patients under the ovulation induction and identify any possible associations with early pregnancy. Materials and methods: A prospective cohort of 80 PCOS women who expressed the desire for fertility was enrolled in this study. All of them received the ovulation induction by using letrozole. Levels of kisspeptin, luteinizing hormone (LH), and estradiol (E2) were measured at three different time points during menstruation. The early pregnancy rate was recorded for the study participants after three ovulation cycles. Results: Kisspeptin levels varied regularly during the menstrual cycle, reaching a peak on the day of hCG injection and decreasing after ovulation. There was no significant correlation between kisspeptin and LH levels. Basal kisspeptin levels decreased after letrozole treatment without a significant difference while LH and E2 levels decreased significantly. PCOS participants who became pregnant early had higher basal kisspeptin levels compared to non-pregnant PCOS patients, which had a significant difference (P = 0.006). And the average basal kisspeptin level in pregnant patients was 2293.0 ± 398.7 pg/ml, with a 95% confidence interval of 1511.5–3074.5 pg/ml. Conclusion: Kisspeptin levels in PCOS women undergoing ovulation induction showed a regular variation, which was similar with the healthy women reported in previous studies. The use of LE may result in PCOS endocrine improvement and fertility achievement. In a certain range, kisspeptin might be a potential predictor for early pregnancy in PCOS patients as people with slightly higher basal kisspeptin levels seemed more likely to be pregnant. [ABSTRACT FROM AUTHOR]

Objective: To evaluate whether trigger and oocyte collection at a smaller follicle size decreases the risk of premature ovulation while maintaining the reproductive potential of oocytes in women with a severely diminished ovarian reserve undergoing modified natural‐cycle in‐vitro fertilization. Methods: This was a retrospective cohort study including women who had at least one unsuccessful cycle (due to no response) of conventional ovarian stimulation with a high dosage of gonadotropins and subsequently underwent a modified natural cycle with a solitary growing follicle (i.e. only one follicle > 10 mm at the time of trigger). The association between follicle size at trigger and various cycle outcomes was tested using regression analyses. Results: A total of 160 ovarian stimulation cycles from 110 patients were included in the analysis. Oocyte pick‐up (OPU) was performed in 153 cycles and 7 cycles were canceled due to premature ovulation. Patients who received their trigger at smaller follicle sizes (≤ 15 mm) had significantly lower rates of premature ovulation and thus higher rates of OPU (98.9% vs 90.8%; odds ratio, 9.56 (95% CI, 1.58–182.9); P = 0.039) compared with those who received their trigger at larger follicle sizes (> 15 mm). On multivariable analysis, smaller follicle sizes at trigger (> 10 to 13 mm, > 13 to 15 mm, > 15 mm to 17 mm) were not associated significantly with a lower rate of cumulus–oocyte complex (COC) retrieval, metaphase‐II (MII) oocytes or blastulation when compared to the > 17‐mm group. On sensitivity analysis including only the first cycle of each couple, the maturity rate among those with COC retrieval was highest in follicle sizes > 15 to 17 mm (92.3%) and > 13 to 15 mm (91.7%), followed by > 10 to 13 mm (85.7%) and lowest in the > 17‐mm group (58.8%). During the study period, five euploid blastocysts developed from 48 fertilized MII oocytes with follicle sizes of 12 mm (n = 3), 14 mm (n = 1) and 16 mm (n = 1) at trigger. Of those, four were transferred and resulted in two live births, both of which developed from follicles with a size at trigger of 12 mm. Conclusions: The ideal follicle size for triggering oocyte maturation may be smaller in women with a severely diminished ovarian reserve managed on a modified natural cycle when compared to conventional cut‐offs. The risk of OPU cancellation was significantly higher in women triggered at follicle size > 15 mm and the yield of mature oocytes was not adversely affected in women triggered at follicle size > 13 to 15 mm compared with > 15 to 17 mm. Waiting for follicles to reach sizes > 17mm may be detrimental to achieving optimal outcome. © 2024 International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

Simple Summary: The goal of this research was to determine if the neurotrophin β-Nerve growth factor is present in the reproductive tract of stallions. This protein has been identified in the semen of camelids and functions to stimulate the release of a hormone from the pituitary of female camelids that is ultimately responsible for the induction of ovulation. β-Nerve growth factor (β-NGF) is a protein produced in the reproductive tract of camelids (camels, llamas, and alpacas) that has been identified as the ovulation inducing factor in seminal plasma. β-NGF from seminal plasma deposited into the reproductive tract of the female camelid acts systemically to stimulate the secretion of luteinizing hormone (LH) from the anterior pituitary, which in turn induces follicle maturation and ovulation. The objectives of the present study were to determine if β-NGF is present in the reproductive tract of the stallion and identify the specific site(s) of production. The hypotheses were that β-NGF would be present in the stallion reproductive tract and would primarily be localized in Sertoli cells of the testes and the prostate gland. Immunohistochemistry on paraffin-embedded paraformaldehyde-fixed tissues was performed using a rabbit polyclonal anti-β-NGF antibody on a total of six male equine reproductive tracts, including a one-day old colt, a one-year-old colt, and four adult stallion tracts. Strong immunostaining was observed in the efferent ducts of the testes and the epithelial cells of the prostate, seminal vesicles, bulbourethral glands, and ampullae. Weaker β-NGF staining was noted in Leydig cells, Sertoli cells, and spermatogonia within the testes and in epithelial cells of the epididymis. In conclusion, immunohistochemistry revealed that β-NGF is present in the stallion reproductive tract, and the protein is primarily present in the efferent ducts of the testes and in all accessory sex glands. [ABSTRACT FROM AUTHOR]

Background and Objectives: Polycystic ovarian syndrome (PCOS) is a widespread endocrine disorder affecting 5–18% of females in their childbearing age. The aim of this study is to assess the efficacy of combining a low dosage of human chorionic gonadotropin (HCG) along with clomiphene citrate (CC) for stimulating ovulation in infertile women diagnosed with CC-resistant PCOS. Materials and Methods: A randomized controlled trial was carried out on 300 infertile CC-resistant PCOS women. All participants were assigned to two groups: the CC-HCG group and the CC-Placebo group. Subjects in the CC-HCG group were given CC (150 mg/day for 5 days starting on the 2nd day of the cycle) and HCG (200 IU/day SC starting on the 7th day of the cycle). Subjects in the CC-Placebo group were given CC and a placebo. The number of ovarian follicles > 18 mm, cycle cancellation rate, endometrial thickness, ovulation rate, clinical pregnancy rate, and occurrence of early ovarian hyper-stimulation syndrome were all outcome variables in the primary research. Results: Data from 138 individuals in the CC-HCG group and 131 participants in the CC-Placebo group were subjected to final analysis. In comparison to the CC-Placebo group, the cycle cancellation rate in the CC-HCG group was considerably lower. The CC-HCG group exhibited a substantial increase in ovarian follicles reaching > 18 mm, endometrial thickness, and ovulation rate. The clinical pregnancy rate was higher in the CC-HCG group (7.2% vs. 2.3%; CC-HCG vs. CC-Placebo). Upon adjusting for BMI and age, the findings of our study revealed that individuals in the CC-HCG group who had serum prolactin levels below 20 (ng/mL), secondary infertility, infertility duration less than 4 years, baseline LH/FSH ratios below 1.5, and serum AMH levels more than 4 (ng/mL) had a higher likelihood of achieving pregnancy. In the CC-Placebo group, there was a greater prediction of clinical pregnancy for those with serum AMH (<4), primary infertility, serum prolactin ≤ 20 (ng/mL), baseline LH/FSH < 1.5, and infertility duration < 4 years. Conclusions: The use of a small dose of HCG along with CC appeared to be an effective treatment in reducing cycle cancelation, improving the clinical pregnancy rate and ovulation rate in CC-resistant PCOS patients. The trial was registered with Clinical Trials.gov, identifier NCT02436226 [ABSTRACT FROM AUTHOR]

Background and Objectives: Fertility tracking apps and devices are now currently available, but urinary hormone levels lack accuracy and sensitivity in timing the start of the 6-day fertile window and the precise 24 h interval of transition from ovulation to the luteal phase. We hypothesized the serum hormones estradiol (E2) and progesterone (P) might be better biomarkers for these major ovulatory cycle events, using appropriate mathematical tools. Materials and Methods: Four women provided daily blood samples for serum E2, P, and LH (luteinizing hormone) levels throughout their entire ovulatory cycles, which were indexed to the first day of dominant follicle (DF) collapse (defined as Day 0) determined by transvaginal sonography; therefore, ovulation occurred in the 24 h interval of Day −1 (last day of maximum diameter DF) to Day 0. For comparison, a MiraTM fertility monitor was used to measure daily morning urinary LH (ULH), estrone-3-glucuronide (E3G), and pregnanediol-3-glucuronide (PDG) levels in three of these cycles. Results: There were more fluctuations in the MiraTM hormone levels compared to the serum levels. Previously described methods, the Fertility Indicator Equation (FIE) and Area Under the Curve (AUC) algorithm, were tested for identifying the start of the fertile window and the ovulation/luteal transition point using the day-specific hormone levels. The FIE with E2 levels predicted the start of the 6-day fertile window on Day −7 (two cycles) and Day −5 (two cycles), whereas no identifying signal was found with E3G. However, both pairs of (E2, P) and (E3G, PDG) levels with the AUC algorithm signaled the Day −1 to Day 0 ovulation/luteal transition interval in all cycles. Conclusions: serum E2 and (E2, P) were better biomarkers for signaling the start of the 6-day fertile window, but both MiraTM and serum hormone levels were successful in timing the [Day −1, Day 0] ovulatory/luteal transition interval. These results can presently be applied to urinary hormone monitors for fertility tracking and have implications for the direction of future fertility tracking technology. [ABSTRACT FROM AUTHOR]

Objective: To explore the impact of the level of differentiation in aminimum of two follicles with a diameter of ≥18 mm on the outcome of controlled ovarian hyperstimulation on the day of human chorionic gonadotropin (hCG) administration. Methods: Single-center data from January 2018 to December 2021 was retrospectively analyzed for 1,199 patients with fresh embryo transfer for assisted reproduction. The absolute value of the standard deviation of the follicle size of at least 2 follicles ≥18 mm in diameter in both ovaries on the day of hCG was taken as the degree of differentiation of the dominant follicle after ovulation induction, based on the standard deviation response to the degree of dispersion of the data. The degree of follicular differentiation was divided into 3 groups according to the size of the value, and the general clinical conditions, laboratory indexes, and clinical outcomes of the patients in the 3 groups were compared. Results: Among the three groups, the body mass index (BMI) of the ≤1s group was lower than that of the other two groups (P< 0.05), while the follicle-stimulating hormone (FSH) and Anti-Mullerian hormone (AMH) were higher (P< 0.05), and the implantation rate and clinical pregnancy rate were significantly higher than those of the other two groups (P< 0.01). After multifactorial logistic regression to correct for confounding factors, with the ≤1s group as the reference, the implantation rate, hCG-positive rate, clinical pregnancy rate and live birth rate of embryo transfer in the ≥2S group were significantly lower (P< 0.01). The results of curve fitting analysis showed that the live birth rate decreased gradually with the increase of the absolute standard deviation (P=0.0079). Conclusion: Differences in follicle diameters ≥18 mm on the day of hCG injection did not have an impact on embryo quality, but had an impact on pregnancy outcomes. The less the variation in follicle size, the more homogeneous the follicle development and the higher the likelihood of live births. [ABSTRACT FROM AUTHOR]

Introduction: Premature ovarian insufficiency (POI) is one of the causes of female infertility. Unexplained POI is increasingly affecting women in their reproductive years. However, the etiology of POI is diverse and remains elusive. We and others have shown that brain-derived neurotrophic factor (BDNF) plays an important role in adult ovarian function. Here, we report on a novel role of BDNF in the Developmental Origins of POI. Methods: Placental BDNF knockout mice were created using CRISPR/CAS9. Homozygous knockout (cKO(HO)) mice didn't survive, while heterozygous knockout (cKO(HE)) mice did. BDNF reduction in cKO(HE) mice was confirmed via immunohistochemistry and Western blots. Ovaries were collected from cKO(HE) mice at various ages, analyzing ovarian metrics, FSH expression, and litter sizes. In one-month-old mice, oocyte numbers were assessed using super-ovulation, and oocyte gene expression was analyzed with smart RNAseq. Ovaries of P7 mice were studied with SEM, and gene expression was confirmed with RT-qPCR. Alkaline phosphatase staining at E11.5 and immunofluorescence for cyclinD1 assessed germ cell number and cell proliferation. Results: cKO(HE) mice had decreased ovarian function and litter size in adulthood. They were insensitive to ovulation induction drugs manifested by lower oocyte release after superovulation in one-month-old cKO(HE) mice. The transcriptome and SEM results indicate that mitochondria-mediated cell death or aging might occur in cKO(HE) ovaries. Decreased placental BDNF led to diminished primordial germ cell proliferation at E11.5 and ovarian reserve which may underlie POI in adulthood. Conclusion: The current results showed decreased placental BDNF diminished primordial germ cell proliferation in female fetuses during pregnancy and POI in adulthood. Our findings can provide insights into understanding the underlying mechanisms of POI. [ABSTRACT FROM AUTHOR]

Background: Women with polycystic ovary syndrome (PCOS) are usually selected to undergo an ovulation induction regimen or a programmed regimen for endometrial preparation in the frozen-thawed embryo transfer (FET) during their IVF/ICSI treatment. The programmed regimen permits flexible scheduling of embryo transfer but requires long-term usage of exogenous estrogen and higher dosages of luteal support while the letrozole ovulation regimen needs lower dosages of luteal support only. Recently, multiple studies have shown that the letrozole ovulation regimen can improve pregnancy outcomes of FET in women with PCOS compared with the programmed regimen. However, most of these studies are retrospective, and prospective studies are urgently needed the evidence from the perspective study is insufficient. Methods/design: We are undertaking a multicentre, randomized, controlled clinical trial of an endometrial preparation regimen for FET in women with PCOS. The eligible women are randomly assigned to either the letrozole ovulation regimen or the programmed regimen for endometrial preparation. The primary outcome is the clinical pregnancy rate. Discussion: The results of this study will provide evidence for whether the letrozole ovulation regimen for endometrial preparation could improve pregnancy outcomes in PCOS women undergoing FET. Trial registration: Chinese Clinical Trial Registry ChiCTR2200062244. Registered on 31 July 2022. [ABSTRACT FROM AUTHOR]

BACKGROUND: Oxidative modification of high-density lipoprotein occurs in patients with polycystic ovary syndrome. However, the relationship between oxidized high-density lipoprotein and ovulation dysfunction and its mechanism are unknown. OBJECTIVE: To investigate the effect and potential mechanism of oxidized high-density lipoprotein on ovarian granulosa cell apoptosis. METHODS: Polycystic ovary syndrome rat model was established, then the high-density lipoprotein was harvested from the rat serum of heart blood. The degree of oxidation of the high-density lipoprotein was detected by high-density lipoprotein inflammation index assay, malondialdehyde assay and lipoprotein agarose gel electrophoresis assay. The normal rat ovarian granulosa cells were isolated and treated with high-density lipoprotein and oxidized high-density lipoprotein isolated from the model rat serum. Cell viability was detected by CCK-8 assay. Cell apoptosis was detected by flow cytometry. The generation of reactive oxygen species was detected by H2DCF-DA staining. The p38 signaling activity was detected by western blot assay. Ovarian granulosa cells were pretreated with reactive oxygen species inhibitors N-acetylcysteine, tetramethylpiperidine (Tempol) and p38 inhibitor SB203580, and then treated with oxidized high-density lipoprotein. Finally, cell apoptosis, reactive oxygen species production and p38 signaling activity were detected. RESULTS AND CONCLUSION: A portion of the high-density lipoprotein from the serum of polycystic ovary syndrome model rats affected oxidative modification. High-density lipoprotein and oxidized high-density lipoprotein isolated from the model rat serum inhibited granulosa cell viability and promoted apoptosis (all P < 0.05). They promoted rat granulosa cell reactive oxygen species production and p38 activation (all P < 0.05). N-acetylcysteine, Tempol and SB203580 reversed oxidized high-density lipoprotein induced granulosa cell apoptosis (all P < 0.05). N-acetylcysteine and Tempol suppressed oxidized high-density lipoprotein-induced p38 activation (all P < 0.05). SB203580 did not have a regulatory effect on reactive oxygen species production (P > 0.05). In summary, polycystic ovary syndrome can promote partial oxidative modification of high-density lipoprotein. The oxidized high-density lipoprotein promotes rat granulosa cell apoptosis by the activation of the reactive oxygen species-initiated p38 signaling pathway. [ABSTRACT FROM AUTHOR]

The physiology of reproduction has been of interest to researchers for centuries. The purpose of this work is to review the development of our knowledge on the neuroendocrine background of the regulation of ovulation. We first describe the development of the pituitary gland, the structure of the median eminence (ME), the connection between the hypothalamus and the pituitary gland, the ovarian and pituitary hormones involved in ovulation, and the pituitary cell composition. We recall the pioneer physiological and morphological investigations that drove development forward. The description of the supraoptic–paraventricular magnocellular and tuberoinfundibular parvocellular systems and recognizing the role of the hypophysiotropic area were major milestones in understanding the anatomical and physiological basis of reproduction. The discovery of releasing and inhibiting hormones, the significance of pulse and surge generators, the pulsatile secretion of the gonadotropin-releasing hormone (GnRH), and the subsequent pulsatility of luteinizing (LH) and follicle-stimulating hormones (FSH) in the human reproductive physiology were truly transformative. The roles of three critical neuropeptides, kisspeptin (KP), neurokinin B (NKB), and dynorphin (Dy), were also identified. This review also touches on the endocrine background of human infertility and assisted fertilization. [ABSTRACT FROM AUTHOR]

Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility. Obesity exacerbates the reproductive complications of PCOS; however, the management of obesity in women with PCOS remains a large unmet clinical need. Observational studies have indicated that bariatric surgery could improve the rates of ovulatory cycles and prospects of fertility; however, the efficacy of surgery on ovulation rates has not yet been compared with behavioural modifications and medical therapy in a randomised trial. The aim of this study was to compare the safety and efficacy of bariatric surgery versus medical care on ovulation rates in women with PCOS, obesity, and oligomenorrhoea or amenorrhoea. In this multicentre, open-label, randomised controlled trial, 80 women older than 18 years, with a diagnosis of PCOS based on the 2018 international evidence-based guidelines for assessing and managing PCOS, and a BMI of 35 kg/m2 or higher, were recruited from two specialist obesity management centres and via social media. Participants were randomly assigned at a 1:1 ratio to either vertical sleeve gastrectomy or behavioural interventions and medical therapy using a computer-generated random sequence (PLAN procedure in SAS) by an independent researcher not involved with any other aspect of the clinical trial. The median age of the entire cohort was 31 years and 79% of participants were White. The primary outcome was the number of biochemically confirmed ovulatory events over 52 weeks, and was assessed using weekly serum progesterone measurements. The primary endpoint included the intention-to-treat population and safety analyses were per-protocol population. This study is registered with the ISRCTN registry (ISRCTN16668711). Participants were recruited from Feb 20, 2020 to Feb 1, 2021. 40 participants were assigned to each group and there were seven dropouts in the medical group and ten dropouts in the surgical group. The median number of ovulations was 6 (IQR 3·5–10·0) in the surgical group and 2 (0·0–4·0) in the medical group. Women in the surgical group had 2.5 times more spontaneous ovulations compared with the medical group (incidence rate ratio 2·5 [95% CI 1·5–4·2], p<0·0007). There were more complications in the surgical group than the medical group, although without long-term sequelae. There were 24 (66·7%) adverse events in the surgical group and 12 (30·0%) in the medical group. There were no treatment-related deaths. Bariatric surgery was more effective than medical care for the induction of spontaneous ovulation in women with PCOS, obesity, and oligomenorrhoea or amenorrhoea. Bariatric surgery could, therefore, enhance the prospects of spontaneous fertility in this group of women. The Jon Moulton Charity Trust. [ABSTRACT FROM AUTHOR]

Introduction: Folliculogenesis and oligo/anovulation are common pathophysiological characteristics in polycystic ovary syndrome (PCOS) patients, and it is also accompanied by gut microbiota dysbiosis. It is known that physical activity has beneficial effects on improving metabolism and promoting ovulation and menstrual cycle disorder in PCOS patients, and it can also modulate the gastrointestinal microbiota in human beings. However, the mechanism remains vague. Irisin, a novel myokine, plays a positive role in the mediating effects of physical activity. Methods: Mice were randomly divided into the control group, PCOS group and PCOS+irisin group. PCOS model was induced by dehydroepiandrosterone (DHEA) and high-fat diet (HFD). The PCOS+irisin group was given irisin 400μg/kg intraperitoneal injection every other day for 21 days. The serum sex hormones were measured by radioimmunoassay. Hematoxylin and Eosin (H&E) Staining and immunohistochemistry (IHC) were conducted on ovarian tissue. The feces microbiota and metabolomic characteristics were collected by 16S rRNA gene sequencing and liquid chromatography-mass spectrometry (LC--MS). Results: In this study, we demonstrated that irisin supplementation alleviated reproductive endocrine disorders of PCOS mice, including estrous cycle disturbance, ovarian polycystic degeneration, and hyperandrogenemia. Irisin also improved the PCOS follicles dysplasia and ovulation disorders, while it had no significant effect on the quality of oocytes. Moreover, irisin could mitigate the decreased bacteria of Odoribacter and the increased bacteria of Eisenbergiella and Dubosiella in PCOS mice model. Moreover, irisin could alleviate the increased fecal metabolites: Methallenestril and PS (22:5(4Z,7Z,10Z,13Z,16Z)/LTE4). Conclusion: These results suggest that irisin may alleviate the status of PCOS mice model by modulating androgen-induced gut microbiota dysbiosis and fecal metabolites. Hence, our study provided evidence that irisin may be considered as a promising strategy for the treatment of PCOS. [ABSTRACT FROM AUTHOR]

Background: Vitamin D binding protein (DBP) might increase substantially after ovarian stimulation and hence could be associated with IVF/ICSI outcomes because it determines the fraction of free bioavailable 25(OH) vitamin D. In this study, we aim to determine whether DBP is associated with E2 level after ovarian stimulation and IVF/ICSI outcomes. Design: Post-hoc analysis of a prospective observational cohort. Setting: Single-center study. Participants: 2569 women receiving embryo transfer. Intervention: None. Main outcome measures: The main outcomes were oocyte and embryo quality as well as pregnancy outcomes. Results: DBP concentration correlates with E2 on hCG day (=day of inducing ovulation with hCG; correlation coefficient r = 0.118, P<0.001) and E2 x-fold change to baseline level (r = 0.108, P<0.001). DBP is also positively correlated with total 25(OH)D (r = 0.689, R2 = 0.475, P<0.001) and inversely with free 25 (OH)D (r=-0.424, R2=0.179, P<0.001), meaning that E2-stimulated DBP synthesis results in a decrease of free 25(OH)D during ovarian stimulation. However, such alteration does not affect IVF/ICSI outcomes when considering confounding factors, such as the number and quality of oocytes nor embryo quality as well as pregnancy outcomes. Conclusion: DBP concentration correlates with the degree of E2 increase after ovarian stimulation. DBP is also positively correlated with total 25(OH)D and inversely with free 25(OH)D, suggesting that the proportion of free 25(OH)D decreases during ovarian stimulation caused by E2-stimulated DBP synthesis. However, such alteration does not affect clinical IVF/ICSI outcomes. [ABSTRACT FROM AUTHOR]

Simple Summary: There is ongoing research regarding the application and efficiency of short-term oestrus synchronisation (ES) treatments using controlled internal drug release (CIDR) in goats raised under subtropical environments, but information regarding the extent of application of these protocols in the tropical region is limited. Although short-term CIDR-based protocols have been more widely studied and applied in the subtropical region, they are still challenged by ethical, technical, and economic issues. Tropical and subtropical regions have moderately seasonal to aseasonal goat breeds, and so, efficient protocols involving a reduced hormonal supply can be developed for the management of reproduction. Therefore, this review provides a scope of the application of short-term CIDR-based protocols and co-treatments and suggests areas of improvement. This review aims to provide an insight into the application and efficiency of CIDR-based protocols for ES in goats raised under tropical and subtropical environments. In temperate regions, short-term CIDR treatments are replacing long-term treatments and sponges used in earlier decades. In addition, the use of co-treatments for the induction of ovulation is gradually changing from hormonal to non-hormonal methods, given the drive towards clean, green, and ethical techniques for reproductive management. Whereas the subtropical region registers ongoing research in the development of new ES protocols, there are few reports from the tropics, particularly Africa, one of the regions with the highest population of goats. Therefore, this calls for research to develop the most appropriate protocols for these regions, since the protocols currently used are largely hormonal based, as they were developed for goats at higher latitudes. Management and environmental factors determine the breeding pattern of goats at tropical latitudes rather than photoperiods, and they are the main causes of reproductive seasonality. The use of ES methods, particularly short-term CIDR-based protocols, along with artificial insemination, may have a significant impact on the productivity of goats in these regions when these factors are controlled. [ABSTRACT FROM AUTHOR]

• gEFS is extremely rare phenomenon among IVF patients. • The pathogenesis of gEFS remain largely elusive. • Pathogenic variants in genes related to HA, folliculogenesis and ovarian function may be considered as a genetic etiology of gEFS. Empty follicle syndrome (EFS) is a condition in which no oocytes are retrieved in an IVF cycle despite apparently normal follicular development and meticulous follicular aspiration following ovulation induction. The EFS is called genuine (gEFS) when the trigger administration is correct. The existence of gEFS is a subject of controversy, and it is quite rare with an undetermined etiology. Genetic defects in specific genes have been demonstrated to be responsible for this condition in some patients. Our objective was to identify novel genetic variants associated with gEFS. We conducted a prospective observational study including 1,689 egg donors from July 2017 to February 2023. WES were performed in patients suffering gEFS. Only 7 patients (0.41 %) exhibited gEFS after two ovarian stimulation cycles and we subsequently performed whole exome sequencing (WES) on these patients. Following stringent filtering, we identified 6 variants in 5 affected patients as pathogenic in new candidate genes which have not been previously associated with gEFS before, but which are involved in important biological processes related to folliculogenesis. These genetic variants included c.603_618del in HMMR , c.1025_1028del in LMNB1 , c.1091-1G > A in TDG , c.607C > T in HABP2 , c.100 + 2 T > C in HAPLN1 and c.3592_3593del in JAG2. As a conclusion, we identified new candidate genes related to gEFS that expand the mutational spectrum of genes related to gEFS.This study show that WES might be an efficient tool to identify the genetic etiology of gEFS and provide further understanding of the pathogenic mechanism of gEFS. [ABSTRACT FROM AUTHOR]

The present study evaluated follicular and endocrine dynamics during ReBreed21, a reproductive strategy that allows resynchronization of ovulation every 21 days in Bos indicus (Nelore) heifers. A synchronized estrous cycle was induced using a standard timed ovulation protocol (d −10: P4 implant inserted + 2 mg estradiol benzoate; d −2: P4 removed+ 0.5 mg cloprostenol + 0.6 mg estradiol cypionate + 200 IU equine chorionic gonadotropin (eCG); d0: 8.4 μg buserelin) without AI to ensure nonpregnancy in heifers. Day of GnRH was designated d0 of estrous cycle. On d12, heifers (n = 80) were randomized into three experimental groups: (1) ReBreed21 (n = 28) d12 P4 device inserted, d19 P4 device withdrawal plus 200 IU eCG, and d21 8.4 μg buserelin (GnRH); (2) ReBreed21+G (n = 26) same as ReBreed21 plus GnRH (16.8 μg) treatment on d12; and (3) Control (n = 26) no treatment. ReBreed21+G increased two-fold (62.9%; 18/26) percentage of heifers with synchronized follicular wave emergence compared to Control (34.6%; 9/26) whereas ReBreed21 (53.6%; 15/28) was intermediate. The ReBreeed21 groups (eCG on d19) increased (P < 0.01) follicular growth between d19 and d21 in ReBreed21 (2.3 ± 0.2 mm) and ReBreed21+G (3.4 ± 0.2 mm) compared with Control (1.2 ± 0.3 mm), resulting in greater (P < 0.01) follicle diameter on d21 for ReBreed21 (10.7 ± 0.4 mm) and ReBreed21+G (10.8 ± 0.4 mm) compared with Control (9.1 ± 0.5 mm). Structural luteolysis was similar among groups (P = 0.51), although the average day when P4 was <1 ng/mL was later (P < 0.01) for ReBreed21 (20.5 ± 0.2) and ReBreed21+G (20.7 ± 0.2) compared to Control (19.2 ± 0.4). Overall ovulation at the end of the estrous cycle was increased (P = 0.03) for ReBreed21 groups (83.3%; 45/54) compared with Control (57.7%; 15/26). Synchronized ovulation on day 22–23 was greater (P < 0.01) for ReBreed21 (78.6%; 22/28) and ReBreed21+G (76.9%; 20/26) compared with Control (30.8%; 8/26). Thus, the ReBreed21 resynchronization program produced acceptable endocrine and follicular dynamics, including synchronized ovulation at the end of the protocol in nonpregnant heifers providing good rationale for testing the fertility and practical implementation of this protocol under field conditions. • The P4 device maintained P4 concentrations and prevented early ovulation. • ReBreed21 strategy (P4+eCG) increased follicle growth rate (d19-21) vs. Control. • ReBreed21 had more synchronized ovulation (d22/23) than Controls (78 vs 27%). • ReBreed21 allows a timed ovulation in nonpregnant Bos indicus heifers every 21 days. [ABSTRACT FROM AUTHOR]

To broadly assess the efficacy of medroxyprogesterone acetate (MPA) for ovulatory suppression during in vitro stimulation compared with gonadotropin-releasing hormone (GnRH) antagonist cycles. Cohort trial. A single academic-affiliated private fertility practice. Patients of all diagnoses aged 18–44 years undergoing autologous in vitro fertilization (IVF) for fertility treatment between 2020 and 2023. Comparison of MPA vs. antagonist IVF stimulation cycles. Rates of premature ovulation, oocyte and embryo yield, embryo quality, pregnancy rates, and logistical benefits. Prospective data was collected on 418 patients who underwent MPA protocol ovarian stimulation (MPA group), which was compared with 419 historical control gonadotropin hormone-releasing hormone antagonist cycles (control group). Age was similar between groups (35.6 ± 4.6 vs. 35.7 ± 4.8 years; P =.75). There were no cases of premature ovulation in the MPA group compared with a total of five cases in the control group (0% vs. 1.2%; risk ratio [RR] = 0.09; 95% confidence interval [CI], 0.01, 1.66). No differences were seen between number of oocytes retrieved (14.3 ± 10.2 vs. 14.3 ± 9.7; P =.83), blastocysts (4.9 ± 4.6 vs. 5.0 ± 4.6; P =.89), or euploid blastocysts (2.4 ± 2.6 vs. 2.2 ± 2.4; P =.18) in the MPA vs. control group respectively. Clinical pregnancy rate was similar between groups (70.4% vs. 64.2%; RR = 0.92; 95% CI, 0.72, 1.18). There was no difference in length of IVF stimulation or dose of stimulation medications. Patients in the MPA group saved an average of $491 ± $119 on medications, had an average of one less monitoring visit (4.4 ± 0.9 vs. 5.6 ± 1.1; P <.01), and 5.0 ± 1.2 less injections per cycle. When adjusting for age and ovarian reserve, protocol group (MPA vs. control) did not influence having an embryo available for transfer (76.6% vs. 73.4%; adjusted RR = 1.05; 95% CI, 0.94, 1.14). For ovulatory suppression during IVF cycles, MPA was effective at preventing ovulation while demonstrating similar cycle and reproductive outcomes, with the additional benefits of patient cost savings, increased convenience with decreased number of visits, and fewer injections. [ABSTRACT FROM AUTHOR]

The objective of the present study was to evaluate the effect of estradiol valerate administered at the beginning of the ovulation synchronization protocol on the pregnancy rate of Bos indicus cows. In the experiments, the following products from MSD, Sao Paulo, Brazil were used: estradiol valerate (EV), estradiol benzoate (EB), intravaginal progesterone device (P4), estradiol cypionate (EC), equine chorionic gonadotropin (eCG) and cloprostenol (PGF). In Experiment 1, Bos indicus cows (n=899) with a body condition score (BCS) of 2.76 ± 0.01 were included in a 3 (device) × 2 (protocol: 5 mg of EV or 2 mg of EB) factorial design. There were three types of P4 devices: a new device (New), a device previously used for 9 days (1×), and a device previously used for 18 days (2×). Nine days later (D9), the P4 device was removed, and cows received 300 IU of eCG. In addition, cows in the EB group received 1 mg of EC and 265 μg of PGF. Timed artificial insemination (TAI) was performed 48 h after P4 device removal in the EB group (TAI48) and 54 h after P4 device removal in the EV group (TAI54). In Experiment 2, Bos indicus cows (n=434) with a BCS of 2.62 ± 0.01 received a new P4 device or one previously used for 9 days and 5 mg of EV. On D9, all cows received 300 IU of eCG, and the P4 devices were removed and distributed in TAI48 and TAI54 cows. In Experiment 3, Bos indicus cows (n=429) with a BCS of 2.80 ± 0.01 were divided into the control and EV/EC groups. All cows received a P4 device. In addition, cows in the control group received 2 mg of EB, and cows in the EV/EC group received 5 mg of EV on D0. On D9, all cows received 1 mg of EC and 300 IU of eCG, and the P4 devices were removed. Cows in the control group also received 265 μg of PGF. All cows were inseminated 48 h after the removal of the P4 device. In Experiment 1, there was no effect of the interaction between protocol and P4 device on the occurrence of estrus (P=0.45) or on the pregnancy per artificial insemination ratio (P/AI; P=0.30). In addition, the occurrence of estrus and P/AI were not different between in the two estradiol groups (P=0.12 and P=0.82) and across the types of intravaginal P4 device (P=0.91 and P=0.47). In Experiment 2, the pregnancy rate was lower (tendency) in TAI48 cows (P=0.07). In Experiment 3, the estrus rate (P=0.12) and P/AI (P=0.56) were similar between the experimental groups. In summary, protocols using estradiol valerate without exogenous ovulation induction require adjustments in the timing of AI from 48 to 54 h after P4 device removal. However, a combination of estradiol valerate at the beginning of the protocol and estradiol cypionate nine days later successfully induced ovulation in Bos indicus cows inseminated 48 h after P4 device removal. • Association of estradiol valerate and estradiol cypionate optimizes TAI protocols. • The use of estradiol cypionate allows AI to be performed 48 h after P4 removal. • Protocols initiated with estradiol valerate do not require PGF. [ABSTRACT FROM AUTHOR]

Most of the northern hemisphere donkey breeds are faced with the risk of extinction, thus donkey reproduction is considered an emerging branch of theriogenology, and the management of artificial insemination and induction of ovulation is a crucial point in setting up preservation protocols. For four consecutive cycles, six jennies' ovarian activity was routinely monitored; an ultrasound examination was performed daily from the evidence of a follicle diameter =27 mm until ovulation. Upon reaching a follicular diameter =32 ± 2 mm (Hour 0), oestrous jennies were treated alternatively with 0.1 mg triptorelin acetate, sc, (TRIP), 0.4 mg/sc of buserelin acetate (BUS) or saline, sc, (CTRL) and examined ultrasonographically at Hours 14, 24, 38, 42, 48, 62 and every 24 h until ovulation. Induction of ovulation was considered successful if ovulation occurred from 24 to 48 h after treatment. 11/12 cycles resulted in ovulation for TRIP and 12/12 for BUS and CTRL groups, respectively. Mean ± SD ovulation time after treatment was 37.3 ± 8.3, 47.1 ± 21.0 and 66.8 ± 25.9 h for BUS, TRIP and CTRL, respectively (p = .0032). Ovulation rates between h24 and h48 were 10/12 (83.3%) for both TRIP/BUS and 2/12 (16.7%) for CTRL, respectively (p = .003). Buserelin and triptorelin-treated jennies had a 25 times higher probability to ovulate between Hours 24 and 48 than controls (p = .003), while there were no jenny and cycle effects on the ovulatory rate. The results of this study show how triptorelin successfully induced ovulation in jennies, like other GnRH analogues previously evaluated. [ABSTRACT FROM AUTHOR]

Simple Summary: This review delves into the oestrus-to-ovulation interval, the potential for ovulation time prediction, and the optimal timing for insemination in dairy cows. Typically, oestrus lasts 10–20 h in dairy cows, with variations attributed to oestrus detection methods and observation frequency. Most cows ovulate around 24–33 h after oestrus onset and 15–22 h after the end of oestrus. The interval from the preovulatory luteinising hormone (LH) surge to ovulation range is approximately 21–30 h, with ovulation occurring at a follicle diameter averaging 18–20 mm. Correctly identifying oestrus onset allows for efficient artificial insemination using the "a.m.–p.m. rule". However, excessively long or short oestrus-to-ovulation intervals may compromise fertility. Heat stress during warm seasons can increase the variability of the oestrus-to-ovulation interval. In cases where insemination timing risks being too early or late relative to ovulation, GnRH administration may be considered to optimize fertility outcomes. This review describes the oestrus-to-ovulation interval, the possibility of predicting the time of ovulation, and the optimum time for insemination relative to oestrus in dairy cows. The duration of oestrus in dairy cows is approximately 8–20 h, with differences possibly related to the methods of oestrus detection and the frequency of observations. Most cows ovulate approximately 24–33 h after the onset of oestrus and 15–22 h after the end of oestrus. The interval from the preovulatory luteinising hormone (LH) surge to ovulation is approximately 4–30 h. Ovulation occurs when follicle diameter averages 18–20 mm. When it is possible to correctly determine the beginning of oestrus, artificial insemination can be performed utilizing the "a.m.–p.m. rule", and only one insemination may be applied. In cows with too long or too short oestrus-to-ovulation intervals, fertility can be compromised. One important factor that can alter the oestrus-to-ovulation interval is acute or chronic heat stress during the warm season. When there is a risk that insemination may occur too early or too late with respect to the time of ovulation, GnRH administration can be considered. [ABSTRACT FROM AUTHOR]

STUDY QUESTION What is the temporal activity and the concentration in follicular fluid (FF) of the anti-inflammatory steroid cortisol during the ovulatory process in humans? SUMMARY ANSWER Intrafollicular concentrations of cortisol become massively upregulated close to ovulation concomitant with an exceptionally high biological activity securing a timely and efficient termination of inflammatory processes. WHAT IS KNOWN ALREADY Ovulation has been described as a local, controlled inflammatory process resulting in the degeneration of the follicle wall which facilitate oocyte extrusion. Ovulation also affects the glucocorticoid metabolism of granulosa cells (GCs) and although de novo synthesis of cortisol only occurs in the adrenal cortex, the mid-cycle surge has been shown to induce a change from high expression of HSD11B2, inactivating cortisol to cortisone, to high expression of HSD11B1 which reversibly catalyses cortisol production from cortisone. Furthermore, high concentrations of progesterone and 17OH-progesterone within follicles may cause dislodging of cortisol from cortisol binding protein (CBP) thereby activating the biological activity of cortisol. STUDY DESIGN, SIZE, DURATION This prospective cohort study included 50 women undergoing fertility treatment according to a standard antagonist protocol at a university hospital-affiliated fertility clinic in Denmark. PARTICIPANTS/MATERIALS, SETTING, METHODS Women donated FF and GCs from one follicle for research purpose aspirated at one of four time points during the process of final maturation of follicles: T  = 0 h, T  = 12 h, T  = 17 h, T  = 32 h. A second sample was collected at oocyte pick up at T  = 36 h. The concentration of cortisol and cortisone together with a range of sex steroids was measured by LC-MS/MS in FF collected at the five time points mentioned above. Whole genome microarray data, validated by q-PCR analysis, was used to evaluate gene expression of CYP11B1 , CYP21A2 , HSD11B1 , HSD11B2 , and NR3C1 in GCs at the same time points. MAIN RESULTS AND THE ROLE OF CHANCE The concentration of cortisol was significantly increased from a few nM at 0 h to around 100–140 nM (P  ≤ 0.0001) at 32–36 h, whilst cortisone was almost constant from 0 to 17 h at a concentration of between 90 and 100 nM being significantly reduced to 25–40 nM (P  ≤ 0.0001) at 32–36 h. This was paralleled by a 690-fold upregulation of HSD11B1 from 0 to 12 h increasing to a more than 20.000-fold change at 36 h. HSD11B2 was quickly downregulated 15- to 20-fold after ovulation induction. Concentrations of progesterone and 17OH-progesterone increased during the ovulatory process to high levels which in essence displaces cortisol from its binding protein CBP due to similar binding affinities. Furthermore, a significant decrease in 11-deoxycortisol expression was seen, but CYP11B1 expression was below detection limit in GCs. LIMITATIONS, REASONS FOR CAUTION The study included women undergoing ovarian stimulation and results may differ from the natural cycle. More observations at each specific time point may have strengthened the conclusions. Furthermore, we have not been able to measure the actual active biological concentration of cortisol. WIDER IMPLICATIONS OF THE FINDINGS For the first time, this study collectively evaluated the temporal pattern of cortisol and cortisone concentrations during human ovulation, rendering a physiological framework for understanding potential dysregulations in the inflammatory reaction of ovulation. STUDY FUNDING/COMPETING INTEREST(S) This research was supported by the University Hospital of Copenhagen, Rigshospitalet, and Novo Nordisk Foundation grant number NNF21OC00700556. Interreg V ÔKS through ReproUnion (www.reprounion.eu); Region Zealand Research Foundation. The funders had no role in study design, collection of data, analyses, writing of the article, or the decision to submit it for publication. The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER N/A. [ABSTRACT FROM AUTHOR]

Background: Due to the high risk of complications in fresh transfer cycles among expected high ovarian response patients, most choose frozen-thawed embryo transfer (FET). There are currently few researches on whether the FET outcomes of expected high ovarian response patients with regular menstrual cycles are similar to those of normal ovarian response. Therefore, our objective was to explore and compare pregnancy outcomes and maternal and neonatal outcomes of natural FET cycles between patients with expected high ovarian response and normal ovarian response with regular menstrual cycles based on the antral follicle count (AFC). Methods: This retrospective cohort study included 5082 women undergoing natural or small amount of HMG induced ovulation FET cycles at the Reproductive Center of the Third Affiliated Hospital of Zhengzhou University from January 1, 2017, to March 31, 2021. The population was divided into expected high ovarian response group and normal ovarian response group based on the AFC, and the differences in patient characteristics, clinical outcomes and perinatal outcomes between the two groups were compared. Results: Regarding clinical outcomes, compared with the normal ovarian response group, patients in the expected high ovarian response group had a higher clinical pregnancy rate (57.34% vs. 48.50%) and live birth rate (48.12% vs. 38.97%). There was no difference in the early miscarriage rate or twin pregnancy rate between the groups. Multivariate logistic regression analysis suggested that the clinical pregnancy rate (adjusted OR 1.190) and live birth rate (adjusted OR 1.171) of the expected high ovarian response group were higher than those of the normal ovarian response group. In terms of maternal and infant outcomes, the incidence of very preterm delivery in the normal ovarian response group was higher than that in the expected high ovarian response group (0.86% vs. 0.16%, adjusted OR 0.131), Other maternal and infant outcomes were not significantly different. After grouping by age (< 30 y, 30–34 y, 35–39 y), there was no difference in the incidence of very preterm delivery among the age subgroups. Conclusion: For patients with expected high ovarian response and regular menstrual cycles undergoing natural or small amount of HMG induced ovulation FET cycles, the clinical and perinatal outcomes are reassuring. For patients undergoing natural or small amount of HMG induced ovulation FET cycles, as age increases, perinatal care should be strengthened during pregnancy to reduce the incidence of very preterm delivery. [ABSTRACT FROM AUTHOR]

Aims and background: The optimal size of the leading follicle at which ovulation trigger should be given in the gonadotropin-releasing hormone (GnRH) antagonist protocol has not been validated yet. We carried out this study to assess the role of delaying ovulation triggering, with the leading follicle beyond 20 mm, in enabling the maturation of medium-sized follicles during controlled ovarian stimulation (COS). Materials and methods: A total of 427 infertile women between the age-group 21 and 45 years, undergoing COS with flexible GnRH antagonist protocol were included, and before stimulation, they were categorized into three groups, namely predicted poor (group I), normal (group II), and hyper (group III) responders. On the day of the trigger, all three groups were further split into two subgroups based on the leading follicle diameter (subgroup A: <20 mm and subgroup B: =20 mm), and assisted reproductive technology (ART) outcomes were analyzed between the subgroups. Results: The number of oocytes retrieved [6.8 ± 3.9 vs 4.0 ± 2.7, 95% confidence interval (CI): 1.10-4.44; p = 0.001], the number of metaphase II oocytes among them (4.6 ± 3.1 vs 2.8 ± 1.9; 95% CI: 0.48-3.06; p = 0.008) and the resultant total number of embryos available for freezing (3.5 ± 2.6 vs 2.2 ± 1.7; 95% CI: 0.17-2.41; p = 0.024) and the number of grade I embryos (2.0 ± 1.9 vs 1.1 ± 1.4; 95% CI: 0.15-1.77; p = 0.021) were significantly increased in group IB when compared to group IA. The cycle outcomes were marginally improved, though not significant, in subgroups IIB and IIIB when compared to subgroups IIA and IIIA, respectively. Oocyte maturation rate and fertilization rate were comparable between the subgroups. Conclusion: Delaying the trigger for oocyte maturation has a role in improving the outcomes in poor responders. Clinical significance: Delaying the ovulation trigger in enabling the maturation of medium-sized follicles leads to clinically better yield of oocytes and good quality embryos in predicted poor responders. [ABSTRACT FROM AUTHOR]

Gamete development is a fundamental process that is highly conserved from early eukaryotes to mammals. As germ cells develop, they must coordinate a dynamic series of cellular processes that support growth, cell specification, patterning, the loading of maternal factors (RNAs, proteins, and nutrients), differentiation of structures to enable fertilization and ensure embryonic survival, and other processes that make a functional oocyte. To achieve these goals, germ cells integrate a complex milieu of environmental and developmental signals to produce fertilizable eggs. Over the past 50 years, Drosophila oogenesis has risen to the forefront as a system to interrogate the sophisticated mechanisms that drive oocyte development. Studies in Drosophila have defined mechanisms in germ cells that control meiosis, protect genome integrity, facilitate mRNA trafficking, and support the maternal loading of nutrients. Work in this system has provided key insights into the mechanisms that establish egg chamber polarity and patterning as well as the mechanisms that drive ovulation and egg activation. Using the power of Drosophila genetics, the field has begun to define the molecular mechanisms that coordinate environmental stresses and nutrient availability with oocyte development. Importantly, the majority of these reproductive mechanisms are highly conserved throughout evolution, and many play critical roles in the development of somatic tissues as well. In this chapter, we summarize the recent progress in several key areas that impact egg chamber development and ovulation. First, we discuss the mechanisms that drive nutrient storage and trafficking during oocyte maturation and vitellogenesis. Second, we examine the processes that regulate follicle cell patterning and how that patterning impacts the construction of the egg shell and the establishment of embryonic polarity. Finally, we examine regulatory factors that control ovulation, egg activation, and successful fertilization. [ABSTRACT FROM AUTHOR]

Kisspeptin is an essential regulator of hypothalamic gonadotropin-releasing hormone release and is required for physiological ovulation. Native kisspeptin-54 can induce oocyte maturation during in vitro fertilization treatment, including in women who are at high risk of ovarian hyperstimulation syndrome. MVT-602 is a potent kisspeptin receptor agonist with prospective utility to treat anovulatory disorders by triggering oocyte maturation and ovulation during medically assisted reproduction (MAR). Currently, the endocrine profile of MVT-602 during ovarian stimulation is unreported. To determine the endocrine profile of MVT-602 in the follicular phase of healthy premenopausal women (phase-1 trial), and after minimal ovarian stimulation to more closely reflect the endocrine milieu encountered during MAR (phase-2a trial). Two randomized, placebo-controlled, parallel-group, dose-finding trials. Clinical trials unit. Healthy women aged 18–35 years, either without (phase-1; n = 24), or with ovarian stimulation (phase-2a; n = 75). Phase-1: single subcutaneous dose of MVT-602 (0.3, 1.0, or 3.0 μg) or placebo, (n = 6 per dose). Phase-2a: single subcutaneous dose of MVT-602 (0.1, 0.3, 1.0, or 3.0 μg; n = 16–17 per dose), triptorelin 0.2 mg (n = 5; active comparator), or placebo (n = 5). Phase-1: safety/tolerability; pharmacokinetics; and pharmacodynamics (luteinizing hormone [LH] and other reproductive hormones). Phase-2a: safety/tolerability; pharmacokinetics; pharmacodynamics (LH and other reproductive hormones); and time to ovulation assessed by transvaginal ultrasound. In both the trials, MVT-602 was safe and well tolerated across the entire dose range. It was rapidly absorbed and eliminated, with a mean elimination half-life of 1.3–2.2 hours. In the phase-2a trial, LH concentrations increased dose dependently; mean maximum change from baseline of 82.4 IU/L at 24.8 hours was observed after administration of 3 μg MVT-602 and remained >15 IU/L for 33 hours. Time to ovulation after drug administration was 3.3–3.9 days (MVT-602), 3.4 days (triptorelin), and 5.5 days (placebo). Ovulation occurred within 5 days of administration in 100% (3 μg), 88% (1 μg), 82% (0.3 μg), and 75% (0.1 μg), of women after MVT-602, 100% after triptorelin and 60% after placebo. MVT-602 induces LH concentrations of similar amplitude and duration as the physiological midcycle LH surge with potential utility for induction of oocyte maturation and ovulation during MAR. EUDRA-CT: 2017-003812-38, 2018-001379-20. [ABSTRACT FROM AUTHOR]

Anti‐Müllerian hormone (AMH) is produced by granulosa cells of the antral follicles. It serves as a promising biomarker for ovarian reserve and responsiveness to ovarian stimulation in humans and domestic animals. This study aimed to validate the AMH Gen II enzyme‐linked immunosorbent assay (ELISA) and correlate ovarian structures with serum AMH concentrations after stimulation treatment in clouded leopards (Neofelis nebulosa). Serum samples were collected from 12 women (age 6.21 ± 3.56 years), and serum AMH concentrations were analysed using AMH Gen II ELISA. The animals were divided into two groups based on ovarian structures [preovulatory follicles (>2 mm) and/or corpora hemorrhagica] along with the presence of uterine tonicity visualized laparoscopically around the time of ovulation. Animals that exhibited these reproductive features were identified as the responder group (n = 9, aged 7.59 ± 2.96 years), whereas those lacking the corresponding features were assigned to the nonresponder group (n = 3, aged 2.06 ± 0.53 years). The intra‐assay coefficient of variation (CV) and interassay CV was 3.56% and 7.75%, respectively. The linearity of AMH dilution was confirmed (r2 =.998), and the percentage of recovery ranged from 93% to 115%. The results demonstrated that overall serum AMH concentrations around the time of ovulation were negatively correlated with age (rs = −.692, p =.013). However, serum AMH concentrations were not correlated with the average number of ovarian structures (rs = −.535, p =.074). Thus, AMH Gen II ELISA was validated in clouded leopards. Around the time of ovulation, serum AMH decreased with advancing age and ovarian responsiveness cannot be evaluated using serum AMH. [ABSTRACT FROM AUTHOR]

Hormonal stimulation of folliculogenesis is a general method of increasing reproductive capacity in rabbits; however, studying the safety of the developed protocols remains an urgent scientific task. The use of hormonal agents is due to the physiological characteristics of rabbits, primarily coitus-dependent mechanisms of ovulation. Applying gonadotropin-releasing analogs depends on mature follicles ready for ovulation in the ovary. It, therefore, has limited effectiveness for rabbits of the "zero" cycle that have not yet given birth. Therefore, such females are recommended to use medications based on gonadotropins obtained from the serum of foal mares (eCG) or human chorionic gonadotropin (hCG). There is limited data on the combined use of gonadotropins, especially the longterm administration in different doses. Thus, the research aimed to conduct a morphological evaluation of rabbit's ovaries with combined serum and chorionic gonadotropins to stimulate folliculogenesis before artificial insemination to assess the safety of the proposed dosages and long-term administration. Stimulation of ovulation in rabbits of experimental groups was caused by the combined use of serum and chorionic gonadotropins (eCG - 400 IU; hCG - 200 IU) for experimental groups 1 and 2 at a dose of 40 IU and 24 IU, respectively. Females of the control group were induced to ovulate by subcutaneous injection of 0.2 ml of gonadotropin-releasing hormone analog. Ovaries were collected on the seventh day of gestation after the euthanasia of the rabbit with prior premedication. After dissection and macroscopic examination, the ovaries were fixed in a 10% aqueous solution of neutral formalin. Histological slides were made according to the general method by pouring in paraffin and subsequent staining with hematoxylin and eosin. The research has established that repeated (during five reproductive cycles) combined use of serum and chorionic gonadotropins has dose-dependent effectiveness and can cause dysfunction of ovaries and blood circulation. Pathological changes may acquire a systemic character with the manifestation of critical conditions for the health and life of rabbits. The stimulating effect of the combined use of eCG and hCG was detected at a dose of 40 IU, and the inhibition of folliculogenesis was observed at 24 IU. Since the premises for the hyperandrogenism were found microscopically, it was essential to investigate the level of androgens in the blood of rabbits after using a dose of 24 IU. At the same time, both doses of gonadotropins affect the reactivity of the endothelium, which is manifested by the presence of intravascular vesicles and changes in the rheological properties of blood. [ABSTRACT FROM AUTHOR]

It is documented that the reproductive performance of postpartum dairy cows is influenced by both internal and external factors. One of the most important reproductive performance indices is the first ovulation postpartum. This review aimed to describe factors affecting first ovulation postpartum in dairy cows, particularly those raised under tropical climates. Negative energy balance and its consequences; metabolic disorders; uterine pathology; udder health; lameness; and heat stress are discussed for their potential effects on the first ovulation postpartum. Understanding the underlying mechanisms of those affecting factors would assist in justifying the treatment and prevention plans in order to optimize the reproductive performance of postpartum dairy cows. [ABSTRACT FROM AUTHOR]

(1) Background: Hormonal fluctuations across the menstrual cycle lead to multiple changes in physiological parameters such as body temperature, cardiovascular function, respiratory rate and perfusion. Electronic wearables analyzing those parameters might present a convenient alternative to urinary ovulation tests for predicting the fertile window. (2) Methods: We conducted a prospective observational study including women aged 18–45 years without current hormonal therapy who used a wrist-worn medical device and urinary ovulation tests for a minimum of three cycles. We analyzed the accuracy of both the retrospective and prospective algorithms using a generalized linear mixed-effects model. The findings were compared to real-world data from bracelet users who also reported urinary ovulation tests. (3) Results: A total of 61 study participants contributing 205 cycles and 6081 real-life cycles from 3268 bracelet users were included in the analysis. The mean error in identifying ovulation with the wrist-worn medical device retrospective algorithm in the clinical study was 0.31 days (95% CI −0.13 to 0.75). The retrospective algorithm identified 75.4% of fertile days, and the prospective algorithm identified 73.8% of fertile days correctly within the pre-specified equivalence limits (±2 days). The quality of the retrospective algorithm in the clinical study could be confirmed by real-world data. (4) Conclusion: Our data indicate that wearable sensors may be used to accurately detect the periovulatory period. [ABSTRACT FROM AUTHOR]

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This study aimed to determine whether 200 μg of GnRH (gonadorelin hydrochloride) would increase ovulatory response and pregnancies per artificial insemination (P/AI) compared with 100 μg at the first GnRH of the breeding-Ovsynch of a Double-Ovsynch program (DO) in lactating Holstein cows. Weekly cohorts of primiparous (n = 719) and multiparous (n = 1,191) cows submitted to DO (GnRH, 7 d later PGF 2α , 3 d later GnRH, 7 d later GnRH [G1], 7 d later PGF 2α [PG1], 1 d later PGF 2α , ∼32 h later GnRH [G2], and ∼16 h later timed artificial insemination [TAI]) for first service, randomly received either 100 μg or 200 μg of GnRH (gonadorelin hydrochloride) at G1 (primiparous, 64–75 DIM; multiparous, 59–70 DIM). Ovulation was determined by ultrasound 2 d after G1 (n = 1,294) and 2 d after G2 (n = 1,020). Blood samples were collected at G1 and at PG1 d to evaluate serum progesterone (P4) concentrations. Conventional (n = 314, Angus; n = 1,084, Holstein) and Holstein sexed semen (n = 276) were used. Pregnancy was diagnosed on d 32, 46, 88, and 200 post-TAI. The high dose of GnRH (200 μg) increased overall ovulatory response to G1 compared with 100 μg (81.3% vs. 65.1%), being similar between parities (primiparous, 72.2%; multiparous, 73.9%). Mean serum P4 concentrations at PG1 did not differ between treatments (100 µg: 9.59 ± 0.15 ng/mL vs. 200 µg: 9.43 ± 0.15 ng/mL). Cows with no ovulation to G1 had higher serum P4 concentrations at G1 than cows with ovulation to G1 (6.27 ± 0.19 ng/mL vs. 4.66 ± 0.07 ng/mL). At PG1, the proportion of cows with functional corpus luteum (98.7% vs. 89.7%) and serum P4 concentrations (9.68 ± 0.12 ng/mL vs. 9.14 ± 0.22 ng/mL) were greater in cows that ovulated to G1 compared with cows that did not ovulate. Also, cows that ovulated to G1 had a greater increase in serum P4 concentrations from G1 to PG1 than cows with no ovulation (5.26 ± 0.12 ng/mL vs. 3.32 ± 0.25 ng/mL). The high dose of GnRH improved overall P/AI at 32 d post-TAI in cows inseminated with conventional semen (54.6% vs. 48.2%) and tended to improve P/AI on 46 (48.8% vs. 44.9%), 88 (47.6% vs. 43.4%), and 200 (45.3% vs. 41.2%) d post-TAI. Primiparous cows inseminated with conventional semen had better P/AI than multiparous cows at d 32 (58.2% vs. 49.4%), 46 (55.1% vs. 44.4%), 88 (53.2% vs. 43.2%) and 200 (51.6% vs. 40.7%) post-TAI. Primiparous cows treated with 200 µg GnRH had lower P/AI on d 32, 46, 88, and 200 post-TAI when inseminated with sexed semen than with conventional semen. In summary, the higher dose of GnRH at G1 improved ovulatory response and P/AI at d 32 post-TAI and tended to improve P/AI at d 46, 88, and 200 post-TAI in cows inseminated with conventional semen. Moreover, the effect of treatment on P/AI in primiparous cows depended on semen type (conventional vs. sexed semen). [ABSTRACT FROM AUTHOR]

A more precise understanding of the commencement of behavioral estrus and pre ovulatory luteinizing hormone (LH) peak and the progesterone (P4) hormonal profile in sheep treated with either FGA‐impregnated sponges or progestagen‐loaded CIDR in short‐term protocols would increase conception rate of fixed timed artificial insemination (FTAI). The present study aim was to investigate the efficiency of different treatments of progestogen with eCG in Sanjabi breed ewes out of breeding season. Fifty Sanjabi ewes were divided equally into sponge (SP) and CIDR groups. At the moment of CIDR or sponge removal (Day 6), the animals were injected with 400IU eCG. Estrous characteristics and reproductive performance were measured in each of the treated groups. The P4 concentration and the characteristics of LH surge were determined. There were no significant differences among the groups CIDR and SP for estrous response, onset, and duration, P4 concentration at device removal, on estrous day, on the 11th and 30th days after device removal, LH surge onset and concentration. Also, there were no significant differences in the conception, lambing, fertility, prolificacy and twining rates in ewes synchronized with either SP or CIDR. The results of this study showed that short‐term (6-days) protocols with FGA and/or CIDRs are equally effective for estrous induction and synchronization and no differences between the two treatments were apparent regarding estrus response, P4 and LH profiles, ovulation, fertility and reproductive performance. Thus, short-term progestagen treatment can be recommended as an alternative to traditional treatment (12-14 days). [ABSTRACT FROM AUTHOR]

The effect of gonadotropin releasing hormone (GnRH) analogue on the ovulatory response of pre-ovulatory follicle (POF) during winter and summer months of the year was studied. A total of 120 crossbred cows brought for insemination with oestrus signs during winter months (December 2022 -January 2023; n=52) and summer months (April - May 2023; n=68) were studied. Oestrus (Day 0) was identified by gynaeco-clinical and ultrasound examination and animals were inseminated with (n =33) or without (n = 87) GnRH analogue (Buserelin acetate 10 mcg; im). The biometry of POF and regressing corpus luteum (RCL) were measured ultrasonographically on Day 0 and the POF was observed every 24 hours until ovulation. The diameters of the POF and RCL on Day 0 were similar between the periods of study. Ovulations occurred on the mean days of 1.00 and 1.37 ±0.18 in GnRH group during summer (S-Gn) and winter months (W-Gn) respectively. The respective mean days in non-GnRH group were 1.14 ±0.05 and 1.33±0.08 during summer (S-O) and winter months (W-O). In S-Gn group all the animals (100%) ovulated on Day 1, when compared to W-Gn animals (62.50%). On exploring the possible effect of RCL on ovulation, significantly increased percentages of ovulations occurred in the contralateral ovary to the ovary having the RCL in GnRH groups and vice-versa in non-GnRH groups. Due to increased percentage of induced ovulations, it could be assumed that GnRH administration on the day of insemination may be beneficial during the summer months of the year. [ABSTRACT FROM AUTHOR]

Ovulation is timed by neural signals originating at the suprachiasmatic nucleus (SCN) that trigger ovulation when converge with high estradiol levels, which indicates the maturation of ovarian follicles. We have shown that the hypothalamic regulation of ovulation is asymmetrical and we hypothesized that the paired SCN could contribute to such symmetries. We unilaterally lesioned the SCN of rats at each stage of the estrous cycle and evaluated the acute effects on the progression of their estrous cycle, follicular development and ovulation. Lesions prevented progression of the estrous cycle when performed in estrus/metestrus but not in diestrus/proestrus. Abnormalities in follicular development were observed in the nonovulating lesioned rats and this was independent of the side of the SCN destroyed and the stage of the cycle when surgery was performed. Groups of lesioned rats were then hormonally primed with GnRH or estradiol to assess the neuroendocrine pathway altered by the treatment. GnRH restored ovulation, suggesting that both SCN are needed for proper triggering of the preovulatory surge of GnRH and that unilateral lesion does not impair the sensitivity of the pituitary or the ovary to GnRH and gonadotropins, respectively. With regard to restoring ovulation, estradiol was asymmetrically effective in rats lesioned in estrous, partially effective in rats operated at diestrus and ineffective in rats at metestrus. Our results indicate that the SCN regulates the activity of the hypothalamic-pituitary-ovarian axis not only by modulating the preovulatory surge of GnRH/gonadotropins but also by promoting the hypothalamic integration of estrogenic signals from the ovaries in an asymmetric and stage-dependent fashion. [ABSTRACT FROM AUTHOR]

Background: Wide range of ovulation distribution is the main restricting factor in establishing the pregnancy following oestrus synchronization (ES) and fixed time insemination (FTI) in sheep. Objectives: Determining the ovulation time (OVT) following ES with two different vaginal devices, its relation to progesterone and conception upon FTI with frozen/thawed semen. Methods: Oestrus was synchronized using either controlled internal drug release (CIDR) (ewe, n = 6; ewe lamb, n = 5) or vaginal sponge (ewe, n = 6; ewe lamb, n = 5) insertion for 12 days, plus Equine chorionic gonadotropin (eCG) at devices removal (Day 0). Sizes of the ovarian follicles were measured using transvaginal probe at −12, 0 and 30–33, 53 h and continued every 3–4 h until 75 h after eCG treatment. Serum progesterone amounts were measured at −12, 0, +2 and +11. Laparoscopic FTI was done at 60.5 ± 0.5 h. Results: The CIDR‐treated group initiated and completed ovulations earlier compared to sponge‐treated females (median: 64 vs. 71 h; p < 0.05). Ewe lambs were ovulated earlier compared to ewes in the sponge‐treated group (66.71 vs. 71.5; p = 0.017). Mean sizes of ovulatory follicles and corpora lutea were not affected by device types. Higher amounts of progesterone were observed in CIDR group compared to sponge‐treated group at device removal (2.68 ± 0.12 vs. 0.30 ± 0.01 ng/mL; p < 0.001). The conception was confirmed in 2/10, and 5/11 females of sponge and CIDR‐treated females, respectively. Conclusions: Types of progestogens influence the OVT, and consequently the result of FTI with frozen/thawed semen. The optimum timespan for FTI should be chosen according to the device types during non‐breeding season. [ABSTRACT FROM AUTHOR]

To investigate the ovarian responses, ovarian and uterine hemodynamics, circulating ovarian hormones, and nitric oxide (NO) with their relations in superstimulated cows. Eight Holstein Friesian dry cows previously synchronized with CIDR underwent rectal Doppler ultrasound scanning and blood sampling after administrating eCG (1500 I.U) on day 10 of the second ovulation (day -5). Cows were treated with 12.5 mg prostaglandin F2α (PGF2α) on days 10 and 17 after ovulation. Estradiol, progesterone, and NO were measured. Results showed that from ≥ 13 follicles, five follicles ovulated from both ovaries. The ovulated follicles increased antrum colored area and colored area % till day -1. The developed corpora lutea (CLs) attained similar diameter, area, colored area, and colored area % from day 2 till day 15. The peak point of velocity (PSV) of uterine arteries decreased while that of ovarian arteries increased from day -4 to day 0. Both ovarian arteries diameter, resistance index (RI), PSV, end velocity (EDV) and systolic/diastolic ratio (S/D) positively correlated (P < 0.0001), but their pulsatility index (PI) negatively correlated (P < 0.0001). The uterine arteries PI, RI, PSV, EDV, time average velocity (TAMV) and S/D negatively correlated (P < 0.0001) but their diameters positively correlated. Estradiol increased but progesterone decreased from day -5 till day 0. After ovulation, P4 reached maximum values on day 9 and started to decrease till day 19.NO showed one peak on day -3 and another one from day 3 to day 9. Conclusions: Blood flow of ovarian arteries is different from uterine arteries and depended on pre- or post-ovulation. [ABSTRACT FROM AUTHOR]

In the current study, efficacy of GnRH, hCG and seminal plasma for the induction of ovulation in dromedary camels during breeding season was investigated. Sixteen female dromedary camels, having ovarian follicle size of 12-19mm, were randomly divided into four equal groups G, H, SP and C. The camels in groups G and H were injected with 2ml (50µg) GnRH analogue and 3000IU of hCG, respectively. Camels in group SP were injected with 1ml seminal plasma mixed with 1ml normal saline and group C (control group) was injected with 1ml normal saline intramuscularly. For the confirmation of ovulation, and CL development, ovaries of experimental camels were examined through trans-rectal ultrasonography on days 1, 2, 3, 8 and 11 post-treatment. The Progesterone ELISA kit was used to determine serum progesterone (P4) concentrations in samples collected on days 0, 3, 6, 8, and 11 of treatment. The results revealed that ovulation rates were 75, 50, 50 and 0% in groups G, H, SP and C, respectively, values for G, H and SP groups were higher compared to group C (p<0.05), while former three groups differed non-significantly from one another. Serum P4 concentrations were <0.5ng/ml in camels of all groups on day 0. However, among ovulated camels, the serum P4 concentration was highest on day 8, when it was 4.80±0.15, 4.15±0.14 and 2.67±0.15ng/ml in SP, H and G groups, respectively; the difference among 3 groups was significant (p<0.05). It was concluded that in dromedary females, use of hormones for the induction of ovulations is an effective option and can safely be used in camel breeding programs, as hormones are easily available compared to seminal plasma. [ABSTRACT FROM AUTHOR]

Polycystic ovary syndrome % (PCOS) is a reproductive endocrine disease characterized by ovulation disorder, hyperandrogenism and/or polycystic ovary. Follicular development disorder caused by PCOS accounts for up to 75% of anovulatory infertility, which is a common cause of infertility and affects up to 15% of reproductive aged women worldwide. Oxidative stress, chronic inflammation, endoplasmic reticulum stress and other pathological conditions coexist in the ovarian microenvironment of PCOS, which are further aggravated under the action of high levels of androgens, synergistically deteriorating the follicular microenvironment, leading to ovulation disorders in PCOS patients. This paper briefly reviewed the research on the mechanism of PCOS ovulation disorder in recent years. [ABSTRACT FROM AUTHOR]

To conduct a systematic review and meta -analysis of all randomized controlled trials (RCTs) that investigated whether dual triggering [a combination of gonadotropin-releasing hormone (GnRH) agonist and human chorionic gonadotropin (hCG)] of final oocyte maturation can improve the number of oocytes retrieved and clinical pregnancy rate in low or normal responders undergoing in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles using a GnRH-antagonist protocol. Studies up to October 2022 were identified from PubMed, Scopus, Cochrane Library and Web of Science. The risk of bias of included studies was assessed. Dichotomous outcomes were reported as relative risks (RR), and continuous outcomes were reported as weighted mean differences (WMD) with 95% confidence intervals (CI). The primary outcomes were number of oocytes retrieved, number of mature [metaphase II (MII)] oocytes, clinical pregnancy rate and ongoing pregnancy rate; other IVF outcomes were considered as secondary outcomes. Seven studies were identified, and 898 patients were eligible for inclusion in this meta -analysis. The results showed that the number of oocytes retrieved [WMD = 1.38 (95% CI 0.47–2.28), I2 = 66%, p = 0.003, low evidence], number of MII oocytes [WMD = 0.7 (95% CI 0.35–1.05), I2 = 42%, p < 0.0001, moderate evidence], number of embryos [WMD = 0.68 (95% CI 0.07–1.3), I2 = 67%, p = 0.03, low evidence] and number of good-quality embryos [WMD = 1.14 (95% CI 0.35–1.93), I2 = 0%, p = 0.005, moderate evidence] in the dual trigger group were significantly higher than in the hCG trigger group. The results of the ovarian response subgroup analysis showed significant differences in all of these outcomes in normal responders, and no differences in any of the outcomes in low responders, except for the number of MII oocytes. In low responders, clinical pregnancy rates may be improved in the dual trigger group [RR = 2.2 (95% CI 1.05–4.61), I2 = 28%, p = 0.04, low evidence]. Dual triggering by GnRH agonist and hCG improved oocyte maturity and embryo grading for normal responders in GnRH-antagonist cycles. Dual triggering for final oocyte maturation may improve clinical pregnancy rates in low responders. [ABSTRACT FROM AUTHOR]

Controlled ovarian hyperstimulation (COH) is a crucial component of assisted reproductive technologies like intrauterine insemination (IUI) and in vitro fertilization (IVF). Triggers in COH play a pivotal role in maturation of the follicles in their final stages and optimizing the timing of egg retrieval, which is very important for the collection of maximum eggs and for a good success rate. Human chorionic gonadotropin (hCG) is used as a standard method for the final follicular maturation and ovulation. HCG has the similar effect as luteinizing hormone (LH) with a half-life of 5-7 days. Now a days, gonadotropin-releasing hormone agonist (GnRH-a) trigger has been used with the target to reduce OHSS for the induction of final follicular maturation and ovulation. Based on the results of various studies, using the GnRH-a trigger leads to defects in the luteal phase resulting in reduced implantation and clinical pregnancy rates and also increasing abortion rates in fresh embryo transfer cycles compared to the routine IVF cycle with hCG triggering. In this review, we examined the benefits, problems and also ways to reform various triggers used for ovulation. [ABSTRACT FROM AUTHOR]