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Background: The optimal outcome of assisted reproductive technology is a successful live birth after fresh embryo transfer. However, the success pregnancy rate of fresh embryo transfer cycle in antagonist protocol is lower than that observed in other protocols. Despite the use of antagonists (GnRH-ant), the incidence of luteinizing hormone surge and elevated progesterone levels remain at approximately 5%-38%. Progesterone is widely recognized to exert adverse effects on fresh embryo transfer outcomes. This study aimed to investigate the impact of luteinizing hormone surge and progesterone levels on live birth rate following fresh embryo transfer and explore appropriate progesterone thresholds to enhance pregnancy outcomes. Methods: This retrospective cohort study included a total of 1,177 antagonist protocol cycles with fresh embryo transfer. The patients were divided into four groups based on the presence of premature LH surge and progesterone level on trigger day>1.5ng/ml. Then, the relationship between the variables and the pregnancy outcome was analyzed and compared in each group. Results: The transient rise of luteinizing hormone did not impact pregnancy outcomes (P=0.345; P=0.3; P=0.787), in contrast to progesterone levels on the day of hCG administration (P=0.047*; P=0.015*; P=0.021*). In cases with luteinizing hormone surge, elevated progesterone levels were correlated with higher antral follicle count (AFC), and as progesterone levels increased, a greater quantity of oocytes and embryos were obtained. However, there was no statistically significant difference in pregnancy outcomes. In cases without luteinizing hormone surge, elevated progesterone levels led to significantly poorer pregnancy outcomes. Furthermore, the curve-fitting and threshold-effect analysis revealed a notable decline in live birth rates when progesterone exceeded or equaled 1.10ng/ml (OR, 0.25; 95% CI, 0.09–0.66; P = 0.005*). Conclusion: The GnRH-ant dosage addition should be carefully selected in flexible antagonist protocols. The presence of elevated progesterone levels may be associated with improved embryo quality when luteinizing hormone surge occurred. In the absence of a luteinizing hormone surge, progesterone levels showed a larger impact on the pregnancy outcome, and fresh embryo transfer should not be performed if the progesterone level on the day of hCG administration is higher than 1.10ng/ml. [ABSTRACT FROM AUTHOR]

Yue Lin,&ast; Qianqian Chen,&ast; Jing Zhu, Yili Teng, Xuefeng Huang, Xia Chen Reproductive Medicine Center, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Xia Chen; Xuefeng HuangReproductive Medicine Center, First Affiliated Hospital of Wenzhou Medical University, 96 Fuxue Road, Wenzhou, Zhejiang, People’s Republic of ChinaTel +86-577-88069380Email chenxia96sz@163.com; xuefhuang0711sz@126.comPurpose: The present study was designed to compare the efficiency of the progestin-primed ovarian stimulation (PPOS) protocol with clomiphene citrate (CC) supplementation (PPOS+CC) and the standard PPOS protocol for women of different ages with diminished ovarian reserve (DOR).Patients and Methods: This retrospective cohort study included 364 DOR women who underwent controlled ovarian stimulation with PPOS+CC (n = 223) or standard PPOS (n = 141). They were divided into subgroups based on age: ≤ 35 years and > 35 years. Differences in baseline characteristics, ovarian stimulation characteristics, endocrinological characteristics, and clinical outcome between the two groups were assessed. Statistical analyses were stratified by age.Results: In all women with DOR, PPOS+CC was associated with a lower percentage of women with profound pituitary suppression than standard PPOS (0.0% vs 18.6%, P < 0.001 and 1.3% vs 11.0%, P = 0.002). In young women with DOR, more high-quality cleavage-stage embryos were harvested (1.96 vs 1.38, P = 0.018) and a lower dosage of gonadotropin per oocyte retrieved was required (558.37 vs 909.82, P = 0.036) in PPOS+CC. In older women with DOR, PPOS+CC led to an increase in the incidence of luteinizing hormone (LH) surge levels above 10 IU/L on trigger day (12.7% vs 4.9%, P = 0.028) and a decrease in the rate of oocyte maturation (84.7% vs 89.9%, P = 0.034) compared to standard PPOS.Conclusion: Clomiphene citrate is an effective adjuvant to alleviate pituitary suppression in PPOS protocols; for young women with DOR, CC supplementation had a positive impact on the number of high-quality embryos. However, older women with DOR would be at risk of developing a premature LH surge and having poor oocyte maturation rate under the PPOS+CC protocol.Keywords: diminished ovarian reserve, clomiphene citrate, medroxyprogesterone acetate, controlled ovarian stimulation, in vitro fertilization, luteinizing hormone surge

Disruptions to the circadian system alter reproductive capacity, particularly in females. Mice lacking the core circadian clock gene, Bmal1, are infertile and have evidence of neuroendocrine disruption including the absence of the preovulatory luteinizing hormone (LH) surge and enhanced responsiveness to exogenous kisspeptin. Here, we explore the role of Bmal1 in suprachiasmatic nucleus (SCN) neuron populations known to project to the neuroendocrine axis. We generated four mouse lines using Cre/Lox technology to create conditional deletion of Bmal1 in arginine vasopressin (Bmal1fl/fl:Avpcre), vasoactive intestinal peptide (Bmal1fl/fl:Vipcre), both (Bmal1fl/fl:Avpcre+Vipcre), and neuromedin-s (Bmal1fl/fl:Nmscre) neurons. We demonstrate that the loss of Bmal1 in these populations has substantial effects on home-cage circadian activity and temperature rhythms. Despite this, we found that female mice from these lines demonstrated normal estrus cycles, fecundity, kisspeptin responsiveness, and inducible LH surge. We found no evidence of reproductive disruption in constant darkness. Overall, our results indicate that while conditional Bmal1 knockout in AVP, VIP, or NMS neurons is sufficient to disrupted locomotor activity, this disruption is insufficient to recapitulate the neuroendocrine reproductive effects of the whole-body Bmal1 knockout.

[Display omitted] • FSHR and LHR were characterized for the first time in elasmobranchs. • FSHR was abundantly expressed in pre-vitellogenic follicles. • LHR was upregulated in vitellogenic follicles and expression peaked in maturing follicles. • A plasma LH-like surge was found before ovulation and egg-capsule formation. • Alternative transcripts of LHR may have differentiated roles in vitellogenesis and maturation. • LHR was downregulated during P4-phase after the LH-like surge. The follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) in cloudy catshark were cloned, and recombinant FSHR and LHR were expressed for characterization. Ventral lobe extract (VLE) from the pituitary contains homologous FSH and LH, and it stimulated the cAMP signaling of FSHR and LHR dose-dependently. Two transcript variants of LHR (LHR-L with exon 10 and LHR-S without) were identified, and LHR-S was the dominant form with higher basal cAMP activity without VLE stimulation. Among various developmental stages of follicles, FSHR expression was mainly associated with the pre-vitellogenic and early white follicles. When follicles were recruited into vitellogenesis, the expression of FSHR decreased while of LHR was upregulated reciprocally, suggesting that LHR may also be responsible for the control of vitellogenesis in chondrichthyans. The expression of LHR-L was upregulated among maturing follicles before ovulation, indicating LHR-L could have a specific role in receiving the LH surge signal for final maturation. Plasma LH-like activity was transiently increased prior to the progesterone (P4)-surge and testosterone-drop at the beginning of P4-phase, supporting a pituitary control of follicle-maturation via LH signaling in chondrichthyans. The expression of follicular LHR was downregulated during the P4-phase when LH-like activity was high, indicating that the LH-dependent downregulation of LHR is conserved in chondrichthyans as it is in other vertebrate lineages. (213 words) [ABSTRACT FROM AUTHOR]

For billions of years before electric light was invented, life on Earth evolved under the pattern of light during the day and darkness during the night. Through evolution, nearly all organisms internalized the temporal rhythm of Earth's 24-hour rotation and evolved self-sustaining biological clocks with a ~24-hour rhythm. These internal rhythms are called circadian rhythms, and the molecular constituents that generate them are called molecular circadian clocks. Alignment of molecular clocks with the environmental light-dark rhythms optimizes physiology and behavior. This phenomenon is particularly true for reproductive function, in which seasonal breeders use day length information to time yearly changes in fertility. However, it is becoming increasingly clear that light-induced disruption of circadian rhythms can negatively impact fertility in nonseasonal breeders as well. In particular, the luteinizing hormone surge promoting ovulation is sensitive to circadian disruption. In this review, we will summarize our current understanding of the neuronal networks that underlie circadian rhythms and the luteinizing hormone surge. [ABSTRACT FROM AUTHOR]

Objective: Progestins are used as an alternative to gonadotropin releasing hormone (GnRH) antagonists to suppress premature luteinizing hormone (LH) surge and a flexible protocol has been defined recently. The aim of this study was to compare the efficacy of flexible protocols with dydrogesterone and GnRH antagonist in suppressing LH surge. Material and Methods: This retrospective, case-control study, was conducted in an infertility unit of a tertiary university hospital. A daily dose of 40 mg dydrogesterone was compared with GnRH antagonist (GnRHant) in controlled ovarian hyperstimulation cycles between July 2018 and July 2019. Dydrogesterone was started when the leading follicle was 12 mm or serum estradiol was over 300 pg/mL. A subgroup analysis of poor responder patients was also performed. Results: In total there were 105 subjects aged between 23 and 41 years, 52 in the dydrogesterone group and 53 in the GnRHant group. Duration of pituitary suppression was longer in dydrogesterone group. Premature ovulation was observed in 11.5% (6/52) and 0% in the dydrogesterone and GnRHant groups, respectively. However, collected oocyte counts and metaphase II oocyte counts were found to be similar between the groups. The six patients with premature ovulation were in poor responder subgroup. Conclusion: Dydrogesterone can be used as an alternative to antagonist regimen in patients where embryo transfer is not planned in the same cycle. However, flexible regimen may not be appropriate in patients with diminished ovarian reserve, as advanced follicular maturation and delayed suppressive effect of oral progesterone may cause premature ovulation. Randomized controlled trials in particular patient groups are required to determine the most effective minimum dose and time of application to ensure treatment success. [ABSTRACT FROM AUTHOR]

Objectives: To compare the use of the luteinizing hormone (LH) surge versus the last menstrual period (LMP) for the accuracy of pregnancy dating in fertile women with a diagnosis of recurrent early pregnancy loss (REPL). Methods: This was an observational cohort study using prospectively collected data at 2 academic REPL programs between 2005 and 2018. Women with a history of REPL and at least 1 subsequent live birth after the evaluation were included. All patients conceived by intercourse timed to the LH surge. Transvaginal ultrasound was examinations were performed 2 weeks after missed menses. The gestational age (GA) was calculated by the LH surge (GALH), LMP (GALMP), and first crown‐rump length (CRL) that measured 5 mm or greater (GACRL). A secondary analysis compared GA based on the first measurable CRL of less than 5 mm versus GA based on the first CRL of 5 mm or greater. The GALH and GALMP were compared to determine which measure showed greater concordance with the CRL. The mean absolute difference in days between the GACRL versus GALH and GACRL versus GALMP was determined. Results: A total of 115 women with 118 subsequent pregnancies resulting in live birth were included, with a mean age at delivery of 35.5 years and a mean of 3.6 prior pregnancy losses. The GALH showed a stronger correlation with the CRL (0.77) than the GALMP (0.63; P =.002). The GALH was more similar to the GACRL than the GALMP, with a mean absolute difference of 2.0 versus 3.1 days (P <.0001). Conclusions: When known, the LH surge appears to be more accurate than the LMP and should be used preferentially for dating of early pregnancy. [ABSTRACT FROM AUTHOR]

Gonadotropes cells located in the anterior pituitary gland are critical for reproductive fitness. A rapid surge in the serum concentration of luteinizing hormone (LH) secreted by anterior pituitary gonadotropes is essential for stimulating ovulation and is thus required for a successful pregnancy. To meet the requirements to mount the LH surge, gonadotrope cells display plasticity at the cellular, molecular and morphological level. First, gonadotrope cells heighten their sensitivity to an increasing frequency of hypothalamic GnRH pulses by dynamically elevating the expression of the GnRH receptor (GnRHR). Following ligand binding, GnRH initiates highly organized intracellular signaling cascades that ultimately promote the synthesis of LH and the trafficking of LH vesicles to the cell periphery. Lastly, gonadotrope cells display morphological plasticity, where there is directed mobilization of cytoskeletal processes towards vascular elements to facilitate rapid LH secretion into peripheral circulation. This mini review discusses the functional and organizational plasticity in gonadotrope cells including changes in sensitivity to GnRH, composition of the GnRHR signaling platform within the plasma membrane, and changes in cellular morphology. Ultimately, multimodal plasticity changes elicited by gonadotropes are critical for the generation of the LH surge, which is required for ovulation.

Introduction Soft stimulation protocols were developed to impart a less stressful and less expensive mode of stimulation for patient insemination. Aim To evaluate the effect of letrozole versus clomiphene citrate (CC) in prevention of premature luteinizing hormone (LH) surge. Patients and methods This is a prospective comparative study held at Obstetrics and Gynecology Department, Alzahraa University Hospital. A total of 90 infertile patients between 18 and 35 years of age with unexplained infertility or mild male factor were included. Overall, 30 patients had induction by human menopausal gonadotropin and then CC from seventh day of the cycle; 30 patients had induction by human menopausal gonadotropin and then letrozole from seventh day of the cycle, and 30 patients had induction by human menopausal gonadotropin only and were evaluated according to LH and estradiol (E2) on triggering day, folliculometry, and pregnancy outcome. Results We found that the letrozole was associated with lesser LH on triggering day and higher endometrial thickness than the other two groups, and CC was associated with higher E2 on triggering day and number of mature follicles than the other two groups. The difference between the study groups in LH, E2, number of mature follicles, and endometrial thickness was statistically significant, whereas the differences in pregnancy rate was statistically insignificant. Conclusion The study shows that clomiphene and letrozole are available options to prevent LH surge. [ABSTRACT FROM AUTHOR]

Gonadotropes cells located in the anterior pituitary gland are critical for reproductive fitness. A rapid surge in the serum concentration of luteinizing hormone (LH) secreted by anterior pituitary gonadotropes is essential for stimulating ovulation and is thus required for a successful pregnancy. To meet the requirements to mount the LH surge, gonadotrope cells display plasticity at the cellular, molecular and morphological level. First, gonadotrope cells heighten their sensitivity to an increasing frequency of hypothalamic GnRH pulses by dynamically elevating the expression of the GnRH receptor (GnRHR). Following ligand binding, GnRH initiates highly organized intracellular signaling cascades that ultimately promote the synthesis of LH and the trafficking of LH vesicles to the cell periphery. Lastly, gonadotrope cells display morphological plasticity, where there is directed mobilization of cytoskeletal processes towards vascular elements to facilitate rapid LH secretion into peripheral circulation. This mini review discusses the functional and organizational plasticity in gonadotrope cells including changes in sensitivity to GnRH, composition of the GnRHR signaling platform within the plasma membrane, and changes in cellular morphology. Ultimately, multimodal plasticity changes elicited by gonadotropes are critical for the generation of the LH surge, which is required for ovulation. [ABSTRACT FROM AUTHOR]

Purpose: To assess the appropriateness of human chorionic gonadotropin (hCG) re‐trigger in poor responders to gonadotropin‐releasing hormone agonist (GnRHa) trigger in controlled ovarian stimulation (COS) cycles. Methods: The 2251 cycles in 2251 patients triggered with GnRHa for oocyte stimulation, with or without requiring hCG re‐trigger between 2013 and 2018, were retrospectively analyzed to compare gonadotropin levels at the start of COS and the rate of normal fertilization between the re‐trigger and non–re‐trigger group. Furthermore, patients in the re‐trigger group were stratified by the rate of normal fertilization (good: ≥60% or poor: <60%) to compare patient demographics, hormone profiles, and clinical outcome between the subgroups. Results: In the re‐trigger group, FSH and LH levels at the start of COS were significantly lower in the good fertilization group than in the poor fertilization group (P <.01). Receiver operating characteristic curves identified cutoff values of the FSH and LH levels of 1.30 and 0.35 mIU/mL, respectively, for predicting ≥60% normal fertilization. Conclusion: Gonadotropin levels at the start of COS are predictors of response to GnRHa trigger and hCG re‐trigger necessity, and may serve as indicators to help clinicians appropriately choose hCG re‐trigger rather than abandoning the cycles or continuing the first oocyte aspiration attempt. [ABSTRACT FROM AUTHOR]

The objective of the study is to determine the effects of clomiphene citrate (CC) on preventing premature luteinizing hormone (LH) surge in infertile patients with polycystic ovary syndrome (PCOS) undergoing intrauterine insemination (IUI). This was a randomized clinical trial being performed at Shiraz Mother and Child Hospital. We included 162 women with PCOS selected for IUI cycles. Patients were randomly allocated to receive 150 mg/day CC from the 8th of the cycle though the day of human chorionic gonadotropin (hCG) injection (n = 81) or nothing in the same period (n = 81). Main outcomes included the incidence of premature LH surge, pregnancy rate, abortion and ongoing pregnancy rates, number of maturing follicles, and endometrial thickness. The incidence of premature LH surge was significantly lower in those who received CC (3.0% vs. 14.9%; P= 0.021). The pregnancy rate was 10 (15.1%) and 6 (8.9%) in CC and control groups, respectively (P = 0.342). The ongoing pregnancy rate found to be comparable between two study groups (12.1% vs. 5.9%; P= 0.068). Serum level of estradiol (E2) level at the time of hCG administration was significantly higher in those who were treated with CC when compared to control (1153.5 ± 326.4 vs. 943.2 ± 215.3; P < 0.001). Patients who received CC also had higher number of mature follicles >18 mm when compared to controls (3.85 ± 1.3 vs. 2.94 ± 1.01; P < 0.001). Administration of CC from the 8th day of the cycle to the day of hCG injection in combination with Gonal-f in infertile patients with CC-resistant PCOS undergoing IUI cycles is associated with decreased incidence of premature LH surge, higher E2levels, and higher number of mature ovarian follicles. This protocol is safe and simple and could be considered to be cost-effective.

Long non-coding RNAs (lncRNAs) and mRNAs are temporally expressed during chicken follicle development. However, follicle transcriptome studies in chickens with timepoints relating to changes in luteinizing hormone (LH) levels are rare. In this study, gene expression in Rohman layers was investigated at three distinct stages of the ovulatory cycle: zeitgeber time 0 (ZT0, 9:00 a.m.), zeitgeber time 12 (ZT12, 9:00 p.m.), and zeitgeber time 20 (ZT20, 5:00 a.m.) representing the early, middle, and LH surge stages, respectively, of the ovulatory cycle. Gene expression profiles were explored during follicle development at ZT0, ZT12, and ZT20 using Ribo-Zero RNA sequencing. The three stages were separated into two major stages, including the pre-LH surge and the LH surge stages. A total of 12,479 mRNAs and 7528 lncRNAs were identified among the three stages, and 4531, 523 differentially expressed genes (DEGs) and 2367, 211 differentially expressed lncRNAs (DELs) were identified in the ZT20 vs. ZT12, and ZT12 vs. ZT0, comparisons. Functional enrichment analysis revealed that genes involved in cell proliferation and metabolism processes (lipid-related) were mainly enriched in the ZT0 and ZT12 stages, respectively, and genes related to oxidative stress, steroids regulation, and inflammatory process were enriched in the ZT20 stage. These findings provide the basis for further investigation of the specific genetic and molecular functions of follicle development in chickens.

Ovulation is an essential phenomenon for reproduction in mammalian females along with follicular growth. It is well established that gonadal function is controlled by the neuroendocrine system called the hypothalamus‐pituitary‐gonadal (HPG) axis. Gonadotropin‐releasing hormone (GnRH) neurons, localized in the hypothalamus, had been considered to be the head in governing the HPG axis for a long time until the discovery of kisspeptin. In females, induction of ovulation and folliculogenesis has been linked to a surge mode and pulse mode of GnRH releases, respectively. The mechanisms of how the two modes of GnRH are differently regulated had long remained elusive. The discovery of kisspeptin neurons, distributed in two hypothalamic nuclei, such as the arcuate nucleus in the caudal hypothalamus and preoptic area or the anteroventral periventricular nucleus in the rostral hypothalamic regions, and analyses of the detailed functions of kisspeptin neurons have led marked progress on the understanding of different mechanisms regulating GnRH surges (ovulation) and GnRH pulses (folliculogenesis). The present review will focus on the role of kisspeptin neurons as the GnRH surge generator, including the sexual differentiation of the surge generation system and factors that regulate the surge generator. Comparative aspects between mammalian species are especially focused on. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the efficacy in suppressing the premature LH surge, embryo quality and pregnancy outcomes of progestin-primed ovarian stimulation (PPOS) protocols using medroxyprogesterone acetate versus utrogestan in women of all ages undergoing in vitro fertilization or intracytoplasmic sperm injection.Methods: 1188 patients were enrolled in the retrospective study, of which 1002 patients were treated with medroxyprogesterone acetate (M group) and recombinant follicle-stimulating hormone (r-FSH)simultaneously from day 3 of the cycle until trigger day, while 186 patients were treated with utrogestan (U group) and r-FSH instead. Viable embryos were cryopreserved for later transfer in both groups. Differences in baseline characteristics, ovarian stimulation characteristics, endocrinological characteristics, embryo development and clinical outcome between two groups were assessed. Statistical analyses were performed stratified by age and number of oocytes retrieved.Results: No significant differences were observed in the baseline characteristics, ovarian stimulation characteristics and clinical outcome of patients between groups. However, blastulation rate in the U group was significantly higher than that in the M group (49.4% vs. 32.9%, P < 0.001). During ovarian stimulation, LH levels remained steady in both groups. Higher percentage of premature LH surge was found in the U group (2.4% vs. 10.2%, P < 0.001), especially for patients aged more than 35 years or who had three oocytes or less retrieved.Conclusions: Both the administration of medroxyprogesterone acetate and utrogestan in PPOS were sufficient to prevent an untimely LH rise, while for patients with poor ovarian response or aged above 35 years, MPA may result in a more satisfactory LH level. PPOS protocol using medroxyprogesterone acetate or utrogestan was comparable in terms of oocytes and pregnancy outcome, whereas the administration of utrogestan may result in an improved blastulation than medroxyprogesterone acetate, which needs further exploration. [ABSTRACT FROM AUTHOR]

The objective of the study is to determine the effects of clomiphene citrate (CC) on preventing premature luteinizing hormone (LH) surge in infertile patients with polycystic ovary syndrome (PCOS) undergoing intrauterine insemination (IUI). This was a randomized clinical trial being performed at Shiraz Mother and Child Hospital. We included 162 women with PCOS selected for IUI cycles. Patients were randomly allocated to receive 150 mg/day CC from the 8th of the cycle though the day of human chorionic gonadotropin (hCG) injection (n = 81) or nothing in the same period (n = 81). Main outcomes included the incidence of premature LH surge, pregnancy rate, abortion and ongoing pregnancy rates, number of maturing follicles, and endometrial thickness. The incidence of premature LH surge was significantly lower in those who received CC (3.0% vs. 14.9%; P = 0.021). The pregnancy rate was 10 (15.1%) and 6 (8.9%) in CC and control groups, respectively (P = 0.342). The ongoing pregnancy rate found to be comparable between two study groups (12.1% vs. 5.9%; P = 0.068). Serum level of estradiol (E2) level at the time of hCG administration was significantly higher in those who were treated with CC when compared to control (1153.5 ± 326.4 vs. 943.2 ± 215.3; P < 0.001). Patients who received CC also had higher number of mature follicles >18 mm when compared to controls (3.85 ± 1.3 vs. 2.94 ± 1.01; P < 0.001). Administration of CC from the 8th day of the cycle to the day of hCG injection in combination with Gonal-f in infertile patients with CC-resistant PCOS undergoing IUI cycles is associated with decreased incidence of premature LH surge, higher E2 levels, and higher number of mature ovarian follicles. This protocol is safe and simple and could be considered to be cost-effective. [ABSTRACT FROM AUTHOR]

Our objectives were to evaluate circulating LH concentrations after intravaginal (IVG) instillation of GnRH analogs in lactating dairy cows. In 2 experiments, lactating Holstein cows (experiment 1: n = 32; experiment 2: n = 47) received the experimental treatments 48 h after the first of 2 PGF2α treatments given 12 h apart and 7 d after a modified Ovsynch protocol (GnRH at −7 d, PGF2α at −24 h, PGF2α at −56 h, GnRH at 0 h). In experiment 1, cows were stratified by parity and randomly allocated to receive the following treatments: 2 mL of saline IVG (SAL, n = 6), 100 µg of gonadorelin (Gon) i.m. (G100-IM, n = 5), and 100 (G100, n = 7), 500 (G500, n = 8), or 1,000 µg of Gon IVG (G1000, n = 7). In experiment 2, treatments were SAL (n = 8), G100-IM (n = 8), G1000 (n = 7), 1,000 µg of Gon plus 10% citric acid (CA) IVG (G1000CA, n = 8), 80 µg of buserelin IVG (B80, n = 8), and 80 µg of buserelin plus 10% CA IVG (B80CA, n = 8). In both experiments, blood was collected every 15 min from −15 min to 4 h, and every 30 min from 4 to 6 h after treatment. Data for area under the curve (AUC), mean LH concentrations, and time to maximum LH concentration were analyzed by ANOVA with (mean LH only) or without repeated measures using PROC MIXED of SAS (version 9.4, SAS Institute Inc., Cary, NC). The proportion of cows with a surge of LH was evaluated with Fisher's exact test using PROC FREQ of SAS. In both experiments, LH concentrations were affected by treatment, time, and the treatment by time interaction. In experiment 1, the AUC for LH and maximum LH concentration were greatest for the G100-IM treatment and were greater for the G1000 than for the SAL and G500 treatments. The proportion of cows with an observed surge of LH was 100 and 0% for cows that received Gon i.m. and IVG, respectively. In experiment 2, the AUC and maximum LH concentrations were greater for the G100-IM, G1000CA, and B80CA treatments than for the other IVG treatments. The proportion of cows with a surge of LH differed by treatment (SAL = 0%, G100-IM = 100%, G1000 = 14%, G1000CA = 88%, B80 = 13%, and B80CA = 100%). For the treatments with a surge of LH, time to maximum concentration of LH was the shortest for the G100-IM treatment, intermediate for the G1000CA treatment, and the longest for cows in the B80CA treatment. In conclusion, Gon (up to 1,000 µg) absorption through intact vaginal epithelium after a single IVG instillation was insufficient to elicit a surge of LH of normal magnitude. Conversely, IVG instillation of 1,000 µg of Gon and 80 µg of buserelin with the addition of citric acid as absorption enhancer resulted in a surge of LH of similar characteristics than that induced after i.m. injection of 100 µg of Gon. [ABSTRACT FROM AUTHOR]

The aim of this immunohistochemical study was to evaluate the distribution of kisspeptin neurons in the preoptic area (POA) of gonadally intact adult male and female rhesus monkeys, and to determine whether imposition of an estradiol (E2)-positive feedback signal in the castrate male increased kisspeptin in the POA. Additionally, kisspeptin in the POA of the intact female was examined during an LH surge induced prematurely by E2 administered in the early follicular phase. The number of kisspeptin neurons in the POA of males and females was similar. Immunoactive kisspeptin perikarya were not observed in the POA of castrate adult males, but such neurons in these animals were present within 12 h of imposing an increment in circulating E2 concentrations that in a screening study conducted 4-6 weeks earlier had elicited an LH surge. As expected, premature induction of an LH surge by E2 early in the follicular phase was associated with upregulation of kisspeptin in the POA. These results represent the first description of immunoreactive kisspeptin cell bodies in the POA of the macaque brain and provide further support for the view that (1) kisspeptin neurons in the POA of the female monkey are a target for the positive feedback action of E2 and (2) the hypothalamic mechanism which mediates this action of E2 in primates is not subjected to perinatal programming by testicular testosterone. Moreover, our findings indicate that maintenance of the kisspeptin content in the POA of intact male monkeys requires the action of E2, presumably generated by aromatization of testicular testosterone at the hypothalamic level. [ABSTRACT FROM AUTHOR]

In women, progesterone suppresses luteinizing hormone ( LH) (gonadotropin-releasing hormone) pulse frequency, but how rapidly this occurs is unknown. In estradiol-pretreated women in the late follicular phase, progesterone administration at 1800 did not slow sleep-associated LH pulse frequency. However, mechanisms controlling LH pulse frequency may differ according to sleep status; and we thus hypothesized that progesterone acutely suppresses waking LH pulse frequency. This was a randomized, double-blind, crossover study of LH secretory responses to progesterone versus placebo administered at 0600. We studied 12 normal women in the late follicular phase (cycle days 7-11), pretreated with 3 days of transdermal estradiol (0.2 mg/day). Subjects underwent a 24-h blood sampling protocol (starting at 2000) and received either 100 mg oral micronized progesterone or placebo at 0600. In a subsequent menstrual cycle, subjects underwent an identical protocol except that oral progesterone was exchanged for placebo or vice versa. Changes in 10-h LH pulse frequency were similar between progesterone and placebo. However, mean LH, LH pulse amplitude, and mean follicle-stimulating hormone exhibited significantly greater increases with progesterone. Compared to our previous study (progesterone administered at 1800), progesterone administration at 0600 was associated with a similar increase in mean LH, but a less pronounced increase in LH pulse amplitude. We conclude that, in estradiol-pretreated women in the late follicular phase, a single dose of progesterone does not suppress waking LH pulse frequency within 12 h, but it acutely amplifies mean LH and LH pulse amplitude - an effect that may be influenced by sleep status and/or time of day. [ABSTRACT FROM AUTHOR]

Steroid positive-feedback activation of the gonadotropin-releasing hormone (GnRH)–pituitary luteinizing hormone (LH) neuroendocrine axis propagates the pre ovulatory LH surge, a crucial component of female reproduction. Our work shows that this key event is restrained by inhibitory metabolic input from hindbrain A2 noradrenergic neurons. GnRH neurons express the ultra-sensitive energy sensor adenosine 5′-monophosphate-activated protein kinase (AMPK); here, we investigated the hypothesis that GnRH nerve cell AMPK and peptide neurotransmitter responses to insulin-induced hypoglycemia are controlled by hindbrain lack of the oxidizable glycolytic end-product l -lactate. Data show that hypoglycemic inhibition of LH release in steroid-primed ovariectomized female rats was reversed by coincident caudal hindbrain lactate infusion. Western blot analyses of laser-microdissected A2 neurons demonstrate hypoglycemic augmentation [Fos, estrogen receptor-beta (ER-β), phosphoAMPK (pAMPK)] and inhibition (dopamine-beta-hydroxylase, GLUT3, MCT2) of protein expression in these cells, responses that were normalized by insulin plus lactate treatment. Hypoglycemia diminished rostral preoptic GnRH nerve cell GnRH-I protein and pAMPK content; the former, but not the latter response was reversed by lactate. Results implicate caudal hindbrain lactoprivic signaling in hypoglycemia-induced suppression of the LH surge, demonstrating that lactate repletion of that site reverses decrements in A2 catecholamine biosynthetic enzyme and GnRH neuropeptide precursor protein expression. Lack of effect of lactate on hypoglycemic patterns of GnRH AMPK activity suggests that this sensor is uninvolved in metabolic-inhibition of positive-feedback-stimulated hypophysiotropic signaling to pituitary gonadotropes. [ABSTRACT FROM AUTHOR]

Background Intragastric or intraperitoneal ethanol (EtOH) treatment inhibits reproductive functions in females and male rats. The area of the hypothalamus where these effects take place is unknown. As the participations of the preoptic-anterior hypothalamic area (POA-AHA) in regulating ovulation is asymmetric, this study aims to analyze the effects on 17 β-estradiol(E2), progesterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) serum levels, the messenger ribonucleic acid ( mRNA) expression of estrogen receptor alpha (ER α) and beta (ER β), and ovulation resulting from unilaterally microinjecting water or an EtOH solution into either side of the POA-AHA. Methods The treatment consisted of microinjecting a 8.6 μM EtOH solution into either side of the POA-AHA. The study was performed on groups of adult cyclic rats at 09.00 hours on diestrus-1, and sacrificed on diestrus-2 at 13.00, on proestrus at 09.00 or 17.00 or on estrus at 09.00 hours. Ovulation rates were assessed in rats sacrificed on estrus. Hormonal serum levels were measured using radioimmunoassay, and as a function of ER α and ER β mRNA expression in each side of the POA-AHA by reverse transcriptase polymerase chain reaction. Results EtOH treatment blocked ovulation and the preovulatory release of LH, and lowered E2 levels. Irrespective of the treated POA-AHA side, ER α mRNA expression was consistently lower in the left POA-AHA and higher on the right. EtOH treatment in the left POA-AHA decreased FSH serum levels and lowered ER β mRNA expression. In turn, EtOH treatment on the right POA-AHA resulted in higher FSH levels and ER β mRNA expression. Conclusions The present results show that EtOH blocks the preovulatory surge of LH on the POA-AHA. The effects of EtOH treatment of preovulatory FSH surge on the POA-AHA are asymmetric (stimulative on the right and inhibiting in the left). The effects of EtOH treatment on preovulatory LH and FSH surge could be explained by the inhibition of ER α and ER β mRNA expression, respectively. [ABSTRACT FROM AUTHOR]

Abstract: The incidence of obesity is increasing rapidly all over the world and results in numerous health detriments, including disruptions in reproduction. However, the mechanisms by which excess body fat interferes with reproductive functions are still not fully understood. After weaning, female rats were treated with a cafeteria diet or a chow diet (control group). Biometric and metabolic parameters were evaluated in adulthood. Reproductive parameters, including estradiol, progesterone, LH and prolactin during the proestrus afternoon, sexual behavior, ovulation rates and histological analysis of ovaries were also evaluated. Cafeteria diet was able to induce obesity in female rats by increasing body and fat pad weight, which resulted in increased levels of triglycerides, total cholesterol, LDL and induced insulin resistance. The cafeteria diet also negatively affected female reproduction by reducing the number of oocytes and preantral follicles, as well as the thickness of the follicular layer. Obese females did not show preovulatory progesterone and LH surges, though plasma estradiol and prolactin showed preovulatory surges similar to control rats. Nevertheless, sexual receptiveness was not altered by cafeteria diet. Taken together, our results suggest that the cafeteria diet administered from weaning age was able to induce obesity and reduce the reproductive capability in adult female rats, indicating that this obesity model can be used to better understand the mechanisms underlying reproductive dysfunction in obese subjects. [Copyright &y& Elsevier]

Objective: To evaluate whether the incidence of luteinizing hormone (LH) rise is reduced by using a flexible compared with a fixed day-6 protocol of GnRH antagonist administration. Design: Randomized controlled trial. Setting: Tertiary university hospital. Patient(s): Patients undergoing in vitro fertilization (n = 146). Intervention(s): Ovarian stimulation was performed using recombinant FSH and GnRH antagonists. GnRH antagonist cetrorelix (0.25 mg/d) was started either on day 6 of stimulation (fixed group) or when LH was >10 IU/L, and/or a follicle with mean diameter >12 mm was present, and/or serum E2 was >150 pg/mL. Patient monitoring was initiated on day 3 of stimulation. Main Outcome Measure(s): Incidence of LH rise. Result(s): No statistically significant difference was observed between the flexible and fixed groups regarding the incidence of LH rise, which was lower in the flexible group (11.0% vs. 15.1%, difference −4.1%, 95% confidence interval −15.4% to +7.1%). No LH surges were observed in any of the patients studied. Conclusion(s): Flexible antagonist administration from day 3 onward does not appear to reduce the incidence of LH rises compared with fixed antagonist administration on day 6 of stimulation. [ABSTRACT FROM AUTHOR]

Passive immunization against inhibin with an anti-inhibin serum (AIS) during the diestrous phase in cycling rats increased follicle-stimulating hormone secretion, stimulated the ovaries and reduced the magnitude of the luteinizing hormone (LH) surge in the afternoon of proestrus. The involvement of gonadotrope progesterone receptor (PR) expression/action in the inhibitory effects of the follicle-stimulating hormone-dependent putative ovarian factor gonadotropin surge-attenuating factor on preovulatory LH secretion was studied in the absence of circulating free inhibin. Proestrous pituitaries from rats injected with AIS or a non-immune serum (NIS) were studied for determination of PR-AB and PR-B mRNAs by RT-PCR and PR-B and PR-A isoform proteins by Western blot. In addition, pituitaries from AIS- and NIS-injected rats were incubated and studied for PR-dependent LH secretion parameters: LH-releasing hormone (LHRH)-stimulated LH secretion, progesterone-potentiated LHRH-stimulated LH secretion and LHRH self-priming. Also, the effects of the antiprogestagen RU486 on these LH secretion parameters were evaluated and compared with those of AIS. Finally, gonadotrope PR phosphorylation was evaluated by immunohistochemistry. Results showed that the hyperstimulated ovaries of AIS-injected rats produce a factor, different from inhibin, that blocked LHRH self-priming and P-potentiation of LHRH-stimulated LH secretion. These effects were not due to decreased pituitary PR mRNAs, PR protein expression or PR protein B/A ratio. The inhibitory effect of AIS on PR-dependent LH secretion seemed to be due to gonadotrope PR dephosphorylation. Taken together, the findings indicated that the putative gonadotropin surge-attenuating factor affected LH surge through an inhibition of PR phosphorylation/action but not PR expression. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Objective: To determine whether a low initial dosage of cetrorelix acetate could prevent a premature luteinizing hormone (LH) surge in women undergoing controlled ovarian stimulation.Method: Treatment with a recombinant follicle stimulating hormone was started on Day 3 of the menstrual cycle, and 0.125 mg of cetrorelix was injected daily from Day 5 of the ovarian stimulation until the diameter of the dominant follicle reached at least 16 mm. The dosage was then doubled and maintained at 0.250 mg/day until the day before the injection of human chorionic gonadotropin.Result: There was a significant decrease in serum LH concentration 1 day after doubling the cetrorelix dosage, and the LH concentration remained low during the follicular phase. Clinical pregnancy occurred in 18 women (42.8%), with 2 intrauterine fetal deaths before the 12th week.Conclusion: Increasing the cetrorelix dosage from 0.125 to 0.250 mg/day when the follicular size is appropriate can prevent a premature LH surge. [ABSTRACT FROM AUTHOR]

Short fertile half-lives of the male and female gametes in the female tract necessitate accurate timing of artificial insemination. We examined the possible association between extension of the estrus to ovulation (E-O) interval and alterations in concentrations of estradiol, progesterone, and the preovulatory LH surge before estrus and ovulation. High-yielding Holstein cows (n = 74 from a total of 106) were synchronized and were examined around the time of the subsequent estrus. They were observed continuously for estrual behavior. Blood samples were collected before and after estrus, and ultrasound checks for ovulation were made every 4 h. About three-quarters of the cows exhibited short (but normal) E-O intervals of 22 to 25 h (25%) or normal intervals of 25 to 30 h (47%); 17% of them displayed a long (but normal) E-O interval of 31 to 35 h, and about 10% exhibited a very long E-O interval of 35 to 50 h. Extended E-O interval comprised estrus-to-LH surge and LH surge-to-ovulation intervals that were both longer than normal. Pronounced changes in hormonal concentrations were noted before ovulation in the very long E-O interval group of cows: progesterone and estradiol concentrations were reduced, and the preovulatory LH peak surge was markedly less than in the other 3 groups. Postovulation progesterone concentrations during the midluteal phase were lesser in the very long and the long E-O interval groups compared with those in the short and normal interval groups. Season, parity, milk yield, and body condition did not affect the estrus to LH surge, LH surge to ovulation, and E-O intervals. The results indicate an association between preovulatory-reduced estradiol concentrations and a small preovulatory LH surge, on the one hand, and an extended E-O interval, on the other hand. Delayed ovulation could cause nonoptimal timing of AI, a less than normal preovulatory LH surge that may be associated with suboptimal maturation of the oocyte before ovulation, or reduced progesterone concentrations before and after ovulation. All may be factors associated with poor fertility in cows with a very long E-O interval. [ABSTRACT FROM AUTHOR]

Background/Aims: The suprachiasmatic nucleus (SCN) is thought to control the timing of luteinizing hormone (LH) surges. The present study was designed to examine temporal patterns of Fos expression in the dorsomedial and ventrolateral parts of the SCN (SCNdm and SCNvl) of female rats during an LH surge. It also included examination of temporal changes in plasma LH levels and temporal changes in Fos levels in the anteroventral periventricular nucleus (AVPV) and gonadotropin-releasing hormone (GnRH) neurons. Methods: Ovariectomized rats injected with 20 μg estradiol benzoate (EB) or vehicle were sacrificed at various times from Zeitgeber time (ZT) 8:00 to 16:30 h (ZT8–16.5; ZT0 = lights on; ZT12 = lights off) on the 2nd day after the injection. Immunohistochemical analyses for Fos and GnRH and enzyme-linked immunosorbent assays for LH were then performed. Results: In both the SCNdm and SCNvl of EB rats, the number of Fos-immunoreactive cells significantly increased between ZT9.5–10.5 and ZT11–12. On the other hand, in EB rats there were significant peaks of LH levels and Fos levels in GnRH neurons and the AVPV between ZT11–12 and ZT13–14. There was no significant difference in the number of Fos-immunoreactive cells between EB and control rats in either the SCNdm or SCNvl at ZT9.5–10.5, or in the SCNdm at ZT11–12, whereas the SCNvl of EB rats contained more Fos-immunoreactive cells than that of control rats at ZT11–12. Conclusion: These results suggest that in female rats during an LH surge, a peak in the Fos level in the SCN precedes peaks in Fos levels in the AVPV and GnRH neurons. Copyright © 2006 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Molinate, a thiocarbamate herbicide, has been reported to impair reproductive capability in the male rat and alter pregnancy outcome in a two-generation study. Published data are lacking on the effects of acute exposure to molinate in the female. Based on this work and our previous observations with related dithiocarbamate compounds, we hypothesized that a single exposure to molinate during the critical window for the neural trigger of ovulation on the day of proestrus (PRO) would block the luteinizing hormone (LH) surge and delay ovulation. To examine the effect of molinate on the LH surge, ovariectomized (OVX) rats were implanted with Silastic capsules containing estradiol benzoate to mimic physiological levels on proestrus. Doses of 25 and 50 mg/kg molinate significantly suppressed LH and prolactin secretion. Intact regularly cycling females gavaged with 0, 25, or 50 mg/kg molinate at 1300 h on PRO were examined on estrus or estrus +1 day for the presence of oocytes in the oviduct. All control females had oocytes in the oviduct on estrus. Molinate doses of 6.25 to 50 mg/kg delayed ovulation for 24 h. Estrous cyclicity was examined after daily exposure to 50 mg/kg (21 days). Estrous cyclicity was irregular in the molinate group, showing extended days in estrus. Two experiments were conducted to determine whether molinate blocked the LH surge via a central nervous system (CNS) mode of action or via an alteration in pituitary response. In the first experiment, we evaluated the release of LH in control and molinate-treated rats after a bolus dose of exogenous GnRH. Luteinizing hormone release was comparable in the two groups, suggesting that the effect of molinate is centrally mediated. To further examine the potential role of the CNS, we examined the pulsatile release of LH present in the long-term OVX females. In this model, the pulsatile pattern of LH secretion is directly correlated with GnRH release from the hypothalamus. A significant decrease in the LH pulse frequency was observed in molinate-treated females. These results indicate that molinate is able to delay ovulation by suppressing the LH surge on the day of proestrus and that the brain is the primary target site for the effects on pituitary hormone secretion. [ABSTRACT FROM PUBLISHER]

A decrease in endogenous opioid peptide inhibitory tone on the afternoon of proestrus is one event underlying generation of the ovulatory luteinizing hormone (LH) surge. Whether this disinhibition involves a complete loss of opioid suppression at the time of the LH surge is controversial. The objective of the present study was to determine whether a total loss specifically of the κ-opioid inhibitory component suppressing LH secretion occurs on proestrus at the onset of the LH surge. Proestrous rats were infused intraventricularly with either artificial cerebrospinal fluid (aCSF) or aCSF containing nor-binaltorphimine (nor-BNI), a selective κ-opioid receptor antagonist, from 15:30 or 16:30 h (the approximate onset time of the spontaneous LH surge) to 18:50 h. The LH surge in rats treated with nor-BNI beginning at 15:30 h started 0.5 h earlier than the spontaneous surge in aCSF controls, and had significantly higher plasma LH levels from 16:30 to 17:30 h. Nor-BNI administration begun at 16:30 h also produced an LH surge with more elevated plasma LH levels at 17:30 and 18:00 h than in aCSF-treated controls. These results demonstrate that significant amounts of κ-opioid tone are still present during the hours when the LH surge is initiated. Thus, a complete loss of κ-opioid inhibition is not required for the onset of the LH surge on proestrus. [Copyright &y& Elsevier]

decrease in inhibitory tone of endogenous opioid peptide on the afternoon of proestrus is one event underlying generation of the ovulatory luteinizing hormone (LH) surge, since premature removal of this inhibitory tone (i.e., disinhibition) results in an early onset of the surge. Our laboratory demonstrated that blockade of κ-opioid receptors in the medial preoptic area (MPOA) advanced the onset of the LH surge on proestrus. Since dynorphin is the endogenous ligand for the κ-opioid receptor, the present studies examined the possible role of dynorphin in this disinhibition response. 1) Neutralization of endogenous dynorphin peptides, by push-pull perfusion of the MPOA with antibodies specific for dynorphin A or A from 1030-1355 h on proestrus, tended to prematurely advance the increase in plasma LH levels normally occurring on this day of the estrous cycle. Although this increase was not statistically significant when compared with controls, plasma LH levels in two antibody-treated rats were sufficiently elevated to cause full ovulation, a response that did not occur in controls. These data suggest that dynorphin A and A might have a role in the MPOA, although a minor one, in suppressing LH secretion early on proestrus. MPOA levels of prodynorphin mRNA decreased at 1700-1800 h on proestrus when plasma LH levels were high, compared with values at 1300-1400 h when plasma LH levels were low. This change did not occur on diestrous d 1 when there was no LH surge. 2) MPOA levels of κ-opioid receptor mRNA did not change on proestrus or diestrous d 1. These results suggest that a reduction in prodynorphin gene expression on the afternoon of proestrus may be one event involved in a possible decrease in dynorphin inhibitory tone on the ovulatory LH surge-generating signal. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine whether prodynorphin-derived opioid peptides could block the spontaneous luteinizing hormone (LH) surge and ovulation, and if so, whether this inhibitory action was mediated through κ-opioid receptors. Various doses of dynorphin peptides (dynorphin A, dynorphin A, dynorphin B, α- and β-neoendorphin) were infused into the brain through third-ventricle cannulae in rats between 1330-1800 h on proestrus. Each dynorphin peptide blocked the LH surge and ovulation in a dose-dependent manner. Dynorphin A and A were equally effective in producing these actions, and more potent than either dynorphin B or α- or β-neoendorphin. U50,488H, a specific κ-opioid receptor agonist, also blocked the LH surge and ovulation. When a mixture of five dynorphin peptides was infused intraventricularly, each at a dose that inhibited the LH surge, both the surge and ovulation were blocked. However, when norbinaltorphimine, a specific κ-opioid receptor antagonist, was coinfused with the mixture of dynorphin peptides, the LH surge and ovulation were fully restored. These results demonstrate that prodynorphin-derived opioid peptides, acting through κ-opioid receptors, can block the LH surge and ovulation. Dynorphin A and A are the most potent in this regard. [ABSTRACT FROM AUTHOR]

Simple Summary: Chicken is one of the most economically important farm poultry, and providing many food products, such as meat and eggs for human consumption. However, follicle transcriptome studies in chickens with timepoints relating to changes in luteinizing hormone level remain unknown. In this study, the largest preovulatory follicle of chicken underwent the early, middle, and terminal stages of ovulatory cycle. Our work provides a comprehensive analysis of lncRNAs and mRNAs in chicken granulosa cells during the ovulatory cycle. A total of 12,479 mRNAs and 7528 lncRNAs were identified among the three stages. Thousands of lncRNAs were annotated, and the most differentially abundant genes were detected in the luteinizing hormone surge stage. Functional features of the lncRNAs and mRNAs at each stage were revealed, which was also associated with the changes in serum luteinizing hormone level. Especially, genes related to oxidative stress, steroids regulation, and inflammatory process were enriched in the luteinizing hormone surge stage, The comprehensive data generated in this study provides the foundation for future investigations to improve the reproductive performance of chickens and explore the mechanisms responsible for female ovarian diseases. Long non-coding RNAs (lncRNAs) and mRNAs are temporally expressed during chicken follicle development. However, follicle transcriptome studies in chickens with timepoints relating to changes in luteinizing hormone (LH) levels are rare. In this study, gene expression in Rohman layers was investigated at three distinct stages of the ovulatory cycle: zeitgeber time 0 (ZT0, 9:00 a.m.), zeitgeber time 12 (ZT12, 9:00 p.m.), and zeitgeber time 20 (ZT20, 5:00 a.m.) representing the early, middle, and LH surge stages, respectively, of the ovulatory cycle. Gene expression profiles were explored during follicle development at ZT0, ZT12, and ZT20 using Ribo-Zero RNA sequencing. The three stages were separated into two major stages, including the pre-LH surge and the LH surge stages. A total of 12,479 mRNAs and 7528 lncRNAs were identified among the three stages, and 4531, 523 differentially expressed genes (DEGs) and 2367, 211 differentially expressed lncRNAs (DELs) were identified in the ZT20 vs. ZT12, and ZT12 vs. ZT0, comparisons. Functional enrichment analysis revealed that genes involved in cell proliferation and metabolism processes (lipid-related) were mainly enriched in the ZT0 and ZT12 stages, respectively, and genes related to oxidative stress, steroids regulation, and inflammatory process were enriched in the ZT20 stage. These findings provide the basis for further investigation of the specific genetic and molecular functions of follicle development in chickens. [ABSTRACT FROM AUTHOR]