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Puberty is the critical developmental transition to reproductive capability driven by the activation of gonadotropin‐releasing hormone (GnRH) neurons. The complex neural mechanisms underlying pubertal activation of GnRH secretion still remain unknown, yet likely include kisspeptin neurons. However, kisspeptin neurons reside in several hypothalamic areas and the specific kisspeptin population timing pubertal onset remains undetermined. To investigate this, we strategically capitalized on the differential ontological expression of the Kiss1 gene in different hypothalamic nuclei to selectively ablate just arcuate kisspeptin neurons (aka KNDy neurons) during the early juvenile period, well before puberty, while sparing RP3V kisspeptin neurons. Both male and female transgenic mice with a majority of their KNDy neurons ablated (KNDyABL) by diphtheria toxin treatment in juvenile life demonstrated significantly delayed puberty onset and lower peripubertal LH secretion than controls. In adulthood, KNDyABL mice demonstrated normal in vivo LH pulse frequency with lower basal and peak LH levels, suggesting that only a small subset of KNDy neurons is sufficient for normal GnRH pulse timing but more KNDy cells are needed to secrete normal LH concentrations. Unlike prior KNDy ablation studies in rats, there was no alteration in the occurrence or magnitude of estradiol‐induced LH surges in KNDyABL female mice, indicating that a complete KNDy neuronal population is not essential for normal LH surge generation. This study teases apart the contributions of different kisspeptin neural populations to the control of puberty onset, demonstrating that a majority of KNDy neurons in the arcuate nucleus are necessary for the proper timing of puberty in both sexes. [ABSTRACT FROM AUTHOR]

In many animals, drastic changes are observed during sexual maturation characterized by the reproductive system development concomitantly to the sexual behavior ontogenesis. These modifications are under the control of internal and external factors such as food. Sexual maturation requires considerable energetic investment, and diet has been shown to affect reproductive activities in many taxonomic groups, especially in insects and vertebrates. By contrast, diet effects on sexual behavior development remain largely unexplored. To elucidate this aspect, we used the male moth Agrotis ipsilon which undergoes sexual maturation occurring between the third and the fifth day postemergence. During this period, males are sensitive to female sex pheromones and a stereotypical sexual behavior characterized by female‐oriented flight takes place. In our study, we compared (1) sex pheromone detection by electroantennography recordings and (2) behavioral response in wind tunnel assays between males fed with different diets found in nature. Compared to standard sucrose diet, males fed with sucrose, fructose, and glucose supplemented with sodium (a mineral element necessary for the locomotor activity in several moths) did not respond better to female sex pheromones but clearly exhibited an earlier behavioral response. Thus, such a diet accelerates the development of sex pheromone‐mediated oriented flight, probably by facilitating the central processing of sex pheromone information in male A. ipsilon moths. Our results provide new information on the influence of nutritional intake on the ontogenesis of male sexual behavior in animals. [ABSTRACT FROM AUTHOR]

The potential threat posed by the invasive species Atlantic blue crab (Callinectes sapidus), through the foraging strategy based on stomach contents and reproductive ecology analysis, was investigated in the hypersaline Mar Menor lagoon (SE Spain). The main groups preyed upon by blue crab were mostly Penaeus kerathurus and Palaemon spp., accounting for 43.3% of their total weight (gravimetric index, %W), teleosts (19.7%W), brachyurans (14.7%W, mostly Carcinus aestuarii), and bivalves (9.9%W, mostly Ruditapes decussatus and Cerastoderma edule). Significant differences were found in feeding habits related to size but not sex. Size at first maturity (L50) was 92 mm for males and 96 mm carapace width (CW) for females. Females showed a seasonal trend in the gonadosomatic index (GSI), which remained high between May and September and peaked in August. Ovigerous females appeared from May until October, peaking in September. The smallest ovigerous specimen found in the lagoon measured 73 mm CW. The number of eggs produced per individual ranged from 284 thousand to 2.2 million, showing a direct correlation with total length. Our results highlight that the blue crab constitutes a threat to the Mar Menor ecosystem, from both the economic and ecological points of view. The blue crab causes major economic damage to local fisheries shortening the average life of fishing gear. It also competes with the fishermen for economically valuable species such as striped prawn, rockpool shrimp, or Mediterranean green crab. We conclude that the blue crab behaves like a dangerous invasive species in the Mar Menor lagoon and further studies are required to design a proper management plan. [ABSTRACT FROM AUTHOR]

Background: Sickle cell anaemia (SCA) is associated with delayed sexual maturation. The Body Mass Index (BMI) or Quetelets Index is closely linked to events of puberty in normal children. We have so far, found no reports on studies on the relationship between BMI and puberty in patients with SCA. Objectives: To evaluate sexual maturation in patients with $CA, and determine the influence of BMI on the onset of sexual maturation. Design: A cross-sectional study carried out in Port Harcourt, Rivers State, from June 1999 to June 2000. Patients and Methods: One hundred and twenty four adolescents with SCA as well as the same number of matched normal controls were evaluated. A structured questionnaire was used to obtain information on personal data and determinants of socio-economic class. Weight, height (HT) and BMI were obtained and sexual maturation assessed. Results: Fifty-seven (46.0 percent) males and 67 (54.0 percent) females with SCA as well as their matched controls were evaluated. The mean age at onset of sexual maturation was 14.61.4 years for males with SCA and 12.1–1.3 years for the controls. Among the females, this was 14.2+1.7 years for the patients and 11.430.8 years for the controls. The observed differences were statistically significant (P

Introduction: Maturation in seawater-adapted (smoltified) male Atlantic salmon is undesirable yet frequently reported in fish weighing up to 1 kg reared under intensive conditions in land-based facilities. Although the photoperiod regulates both smoltification and maturation, the optimal post-smoltification regimen for the prevention of maturation is unclear. Methods: In this study, mixed-sex Atlantic salmon weighing 95 g were exposed to three different photoperiod regimes: continuous daylength, gradually decreasing daylength, and short-to-long daylength after the induction of smoltification by the "winter signal" (12 h:12 h light:dark). Fish were maintained under these conditions in triplicate for 18 weeks in a brackish water flow-through system at 12℃ and with a salinity of 20 ppt. This initial phase was followed by a grow-out period (1 kg-2.5 kg) in seawater (32-ppt salinity) at 13℃ for 11 weeks, with exposure to decreasing daylength. Throughout the 29-week study, body condition, gonad development, and morphological traits were assessed. Additionally, during exposure to brackish water, serum 11-ketotestosterone (11-KT) levels were quantified, and the testes were examined histologically. Upon termination of the study, the maturation rate was determined. Results: This study exclusively detected maturation among male salmon. Under continuous light exposure, the number of fish initiating maturity steadily increased from week 8 and continued to increase in the subsequent samplings. In the short-to-long daylength group, a subset of male fish showed elevated 11-KT levels at week 14, although their gonadal development and morphological changes were not evident until week 18. Male fish exposed to decreasing daylength showed no substantial increase in 11-KT levels, although a few fish exhibited advanced gonad development by week 18. At the end of the trial, markedly lower percentages of maturing and fully mature male fish were observed among those fish previously exposed to decreasing daylength. The maturation rates at study termination were 44.4% for the short-to-long daylength group, 29.4% for the continuous daylength group, and 4.3% for the decreasing daylength group. Discussion: These results show that photoperiod can be utilized to regulate maturation in male Atlantic salmon. In addition, decreasing the photoperiod after smoltification seems to limit early sexual maturation without compromising body size development. Thus, decreasing the photoperiod could be utilized to limit maturation in the production of post-smolt salmon or salmon in landbased facilities. [ABSTRACT FROM AUTHOR]

The hypothalamus is an essential neuroendocrine area in animals that regulates sexual development. Long non-coding RNAs (lncRNAs) are hypothesized to regulate physiological processes related to animal reproduction. However, the regulatory mechanism by which lncRNAs participate in sexual maturity in goats is poorly known, particularly from birth to sexual maturation. In this study, RNAseq analysis was conducted on the hypothalamus of four developmental stages (1day (D1, n = 5), 2 months (M2, n = 5), 4months (M4, n = 5), and 6 months (M6, n = 5)) of Jining grey goats. The results showed that a total of 237 differentially expressed lncRNAs (DELs) were identified in the hypothalamus. Among these, 221 DELs exhibited cis-regulatory effects on 693 target genes, while 24 DELs demonstrated trans-regulatory effects on 63 target genes. The target genes of these DELs are mainly involved in biological processes related to energy metabolism, signal transduction and hormone secretion, such as sphingolipid signaling pathway, adipocytokine signaling pathway, neurotrophic signaling pathway, glutamatergic synapse, P53 signaling pathway and GnRH signaling pathway. In addition, XR_001918477.1, TCONS_00077463, XR_001918760.1, and TCONS_00029048 and their potential target genes may play a crucial role in the process of goat sexual maturation. This study advances our understanding of lncRNA in hypothalamic tissue during sexual maturation in goats and will give a theoretical foundation for improving goat reproductive features. [ABSTRACT FROM AUTHOR]

We collected larvae of the Patch-nosed Salamander, Urspelerpes brucei, and analyzed size-frequency distributions throughout a 12-mo cycle to determine the length of the larval period and size at metamorphosis. The hatchling-size class entered the population across a wide time window, from early winter to late summer, and at a minimal size of 6-mm snout–girdle length (SGL). Examination of both pooled total sample and the samples across six seasonal periods strongly show that the typical larval period is approximately 24 mo, with metamorphosis occurring during late summer to early fall at 18–19 mm SGL. Because oviposition and hatching are extended across several months, it is possible that some animals metamorphose up to 30 mo after hatching. Larval growth in Urspelerpes is 0.5 mm/mo, which is comparable—and even slower—to the slow larval growth seen in all other stream-dwelling plethodontid larvae. Our samples of recently metamorphosed animals and mature adults indicate that males are sexually mature at metamorphosis. This is more difficult to know for females, and we suggest that females may be a mixed group that contains individuals that mature at metamorphosis and individuals that delay maturation for an additional 12 mo. There is no difference in either sex between body size at metamorphosis and at sexual maturation. As in other species in the Spelerpini, the timing of metamorphosis and the timing of sexual maturation appear to be able to evolve independently, with the remarkable result that the early sexual maturation in Urspelerpes results in a tiny adult size despite having a multiyear larval period. [ABSTRACT FROM AUTHOR]

To describe the duration, timing, tempo, and synchronicity of puberty, as well as the correlation between timing and tempo of puberty. Overall, 15,819 of 22,439 invited children participated in the Puberty Cohort within the Danish National Birth Cohort. Participants completed a web-based questionnaire every 6 months through maturation with questions on current pubertal status. Girls reported current Tanner stage of breast and pubic hair development, and timing of menarche. Boys reported current Tanner stage of genital and pubic hair development, timing of first ejaculation, and vocal changes. While accounting for this interval-censored puberty information, we estimated the duration of puberty. Then, we used a nonlinear mixed effect growth model to estimate timing, tempo, synchronicity of puberty, and correlation between timing and tempo of puberty. In girls, the average duration of breast development was longer, whereas the average tempo was slower than pubic hair development. The average timing of breast development was earlier than the average timing of pubic hair development. The majority of girls had asynchronous puberty. In boys, the average duration was longer and average tempo slower for genital than pubic hair development. The average timing of genital and pubic hair development were comparable; hence, the majority had synchronous pubertal development. Adolescents who had earlier timing also tended to have a faster tempo. Being one of the largest puberty cohorts worldwide, these unique contemporary data can help physicians, parents, and children to understand and anticipate expected progression through pubertal development. [ABSTRACT FROM AUTHOR]

Sexual maturation in many fishes requires a major physiological change that involves a rapid transition between energy storage and usage. In Atlantic salmon, this transition for the initiation of maturation is tightly controlled by seasonality and requires a high‐energy status. Lipid metabolism is at the heart of this transition since lipids are the main energy storing molecules. The balance between lipogenesis (lipid accumulation) and lipolysis (lipid use) determines energy status transitions. A genomic region containing a transcription co‐factor of the Hippo pathway, vgll3, is the main determinant of maturation timing in Atlantic salmon. Interestingly, vgll3 acts as an inhibitor of adipogenesis in mice and its genotypes are potentially associated with seasonal heterochrony in lipid storage and usage in juvenile Atlantic salmon. Here, we explored changes in expression of more than 300 genes directly involved in the processes of adipogenesis, lipogenesis and lipolysis, as well as the Hippo pathway in the adipose tissue of immature and mature Atlantic salmon with distinct vgll3 genotypes. We found molecular evidence consistent with a scenario in which immature males with different vgll3 genotypes exhibit contrasting seasonal dynamics in their lipid profiles. We also identified components of the Hippo signalling pathway as potential major drivers of vgll3 genotype‐specific differences in adipose tissue gene expression. This study demonstrates the importance of adipose gene expression patterns for directly linking environmental changes with energy balance and age at maturity through genetic factors bridging lipid metabolism, seasonality and sexual maturation. [ABSTRACT FROM AUTHOR]

To understand the habitat status of Pholas orientalis offshore of Selangor, which is an important fishing ground in Malaysia, P. orientalis was obtained from the region in August and November 2014. The shell sizes and weights of the specimens were measured, and tissue sections of various organs were prepared, stained with hematoxylin and eosin solution, and observed under a light microscope. The results obtained for the gonads, digestive tube, and midgut gland were summarised, and the results showed that many individuals of both sexes had already reached the mature stage in August, and the maturation was almost synchronised in both sexes. In November, more than 40% of both sexes entered the spawning stage, suggesting that the spawning peak in the region occurred during the rainy season. From observations of the presence or absence of food in the digestive tube and epithelium condition estimation of the midgut gland, food presence in the clams was confirmed in more than 80% of individuals in both months, and the epithelium condition was also good. In addition, from the Global Eutrophication Watch internet homepage, chlorophyll-a concentration data on the fishing ground area were shown as the stable phytoplankton occurrence area. Therefore, these data suggest that suitable food availability is an important factor for the habitation of this species.

The mechanisms regulating puberty still remain elusive, as do the underlying causes for sex differences in puberty onset (girls before boys) and pubertal disorders. Neuroendocrine puberty onset is signified by increased pulsatile GnRH secretion, yet how and when various upstream reproductive neural circuits change developmentally to govern this process is poorly understood. We previously reported day-by-day peri-pubertal increases (Kiss1, Tac2) or decreases (Rfrp) in hypothalamic gene expression of female mice, with several brain mRNA changes preceding external pubertal markers. However, similar pubertal measures in males were not previously reported. Here, to identify possible neural sex differences underlying sex differences in puberty onset, we analyzed peri-pubertal males and directly compared them with female littermates. Kiss1 expression in male mice increased over the peri-pubertal period in both the AVPV and ARC nuclei but with lower levels than in females at several ages. Likewise, Tac2 expression in the male ARC increased between juvenile and older peri-pubertal stages but with levels lower than females at most ages. By contrast, both DMN Rfrp expressionand Rfrp neuronal activation strongly decreased in males between juvenile and peri-pubertal stages, but with similar levels as females. Neither ARC KNDy neuronal activation nor Kiss1r expression in GnRH neurons differed between males and females or changed with age. These findings delineate several peri-pubertal changes in neural populations in developing males, with notable sex differences in kisspeptin and NKB neuron developmental patterns. Whether these peri-pubertal hypothalamic sex differences underlie sex differences in puberty onset deserves future investigation.

The development of oestrogen positive feedback is a hallmark of female puberty. Both oestrogen and progesterone signalling are required for the functioning of this neuroendocrine feedback loop but the physiological changes that underlie the emergence of positive feedback remain unknown. Only after puberty does oestradiol (E2) facilitate progesterone synthesis in the rat female hypothalamus (neuroP), an event critical for positive feedback and the LH surge. We hypothesize that prior to puberty, these astrocytes have low levels of membrane oestrogen receptor alpha (ERα), which is needed for facilitation of neuroP synthesis. Thus, we hypothesized that prepubertal astrocytes are unable to respond to E2 with increased neuroP synthesis due a lack of membrane ERα. To test this, hypothalamic tissues and enriched primary hypothalamic astrocyte cultures were acquired from prepubertal (postnatal week 3) and post-pubertal (week 8) female mice. E2-facilitated neuroP was measured in the hypothalamus pre- and post-puberty, and hypothalamic astrocyte responses were measured after treatment with E2. Prior to puberty, E2-facilitated neuroP synthesis did not occur in the hypothalamus, and mERα expression was low in hypothalamic astrocytes, but E2-facilitated neuroP synthesis in the rostral hypothalamus and mERα expression increased post-puberty. The increase in mERα expression in hypothalamic astrocytes corresponded with a post-pubertal increase in caveolin-1 protein, PKA phosphorylation, and a more rapid [Ca2+ ]i flux in response to E2. Together, results from the present study indicate that E2-facilitated neuroP synthesis occurs in the rostral hypothalamus, develops during puberty, and corresponds to a post-pubertal increase in mERα levels in hypothalamic astrocytes.

Mesozoic fossils of frogs are rare in the palaeontological record, particularly those exhibiting soft tissues that offer limited insights into early life-history characteristics. Here we report on a skeletally immature frog from the Lower Cretaceous of northwest China, with egg masses in the body and eggs in the oviduct, indicative of a gravid female. CT reconstruction of the specimen allows referral to Gansubatrachus qilianensis and we assign it as a paratype complementing the diagnosis of the type species. The new fossil, which might represent a younger individual than the holotype of Gansubatrachus, shows that sexual maturation occurred before full adulthood in this frog and provides evidence of death linked to mating behaviour. We also discuss other potential sources of variation and life-history traits of Gansubatrachus. The new finding represents the oldest Early Cretaceous frog preserving in situ eggs and provides a glimpse into ancient anuran development during Mesozoic times. [ABSTRACT FROM AUTHOR]

To investigate the possible effect of different feed ration levels on the growth, welfare, and early maturation of juvenile Atlantic salmon, 450 salmon parr with a mean (±standard error) initial weight of 51.6 g (±0.8) were reared in triplicate under three different feed ration levels for five months. The control group (100r) was fed every day, the 50r group was fed every other day, and the 33r group was fed every third day. In every group, 75 fish (half of the group) were individually tagged for monitoring of growth. The number of fin wounds was used as the welfare indicator, and to inspect the development of maturation, all fish were euthanized, and development of the gonads was monitored by visual inspection at the termination of the trial. The control group (100r) showed a significantly higher specific growth rate (0.90% day−1) compared to the lower fed groups (50r, 0.67% day−1 and 33r, 0.49% day−1); however, the growth difference was 21–24% less than expected solely on the difference in the amount of feed given to each group. The 100r group showed the highest welfare rating, and the 33r group the lowest possible, indicating more aggressive behaviour and fin biting due to feed restriction in the 33r group. No difference (p > 0.45) was found in the development of maturation in females, but the combined numbers of males in maturity stages 2–5 showed an overall trend towards slower maturation in the 33r group compared to the 100r group. Although the present findings on the development of sexual maturation were subtle due to the limited time frame of the trial, the findings offer a foundation for future investigation into the relationship between the feed ration level and the development of sexual maturation in the rearing of juvenile Atlantic salmon. [ABSTRACT FROM AUTHOR]

Background: The decrease in physical activity after adolescence seems to be more related to biological age than to chronological age. The sexual maturation may explain this decline in physical activity in adolescents. Aims: This study aimed to verify the interaction of sexual maturation with sex, nutritional status, and socioeconomic condition in association with insufficient physical activity of 3979 students, of both sexes, aged between 11 and 19 years of public schools from two cities in southern Brazil adolescents. Methods: Measurements of body mass, height, sexual maturation, socioeconomic condition, and level of physical activity were collected. Poisson regression analyzed the association and interaction with insufficient physical activity providing prevalence ratios (PR) with 95% confidence intervals and p < 0.05. Results: Girls regardless of the pubertal stage and students of middle and low economic classes were more likely to be insufficiently active. The likelihood of girls being insufficiently active increases with the pubertal stage. Conclusion: Special attention should be paid to girls and students of intermediate and low economic classes. [ABSTRACT FROM AUTHOR]

Sertoli cells (Sc) are the sole target of follicle-stimulating hormone (FSH) in the testis and attain functional maturation post-birth to significantly augment germ cell (Gc) division and differentiation at puberty. Despite having an operational microRNA (miRNA) machinery, limited information is available on miRNA-mediated regulation of Sc maturation and male fertility. We have shown before that miR-92a-3p levels decline in pubertal rat Sc. In response to FSH treatment, the expressions of FSH Receptor, Claudin11 and Klf4 were found to be elevated in pubertal rat Sc coinciding with our finding of FSH-induced decline in miR-92a-3p levels. To investigate the association of miR-92a-3p and spermatogenesis, we generated transgenic mice where such pubertal decline of miR-92a-3p was prevented by its overexpression in pubertal Sc under proximal Rhox5 promoter, which is known to be activated specifically at puberty, in Sc. Our in vivo observations provided substantial evidence that FSH-induced decline in miR-92a-3p expression during Sc maturation acts as an essential prerequisite for the pubertal onset of spermatogenesis. Elevated expression of miR-92a-3p in post-pubertal testes results into functionally compromised Sc, leading to impairment of the blood-testis barrier formation and apoptosis of pre-meiotic Gc, ultimately culminating into infertility. Collectively, our data suggest that regulation of miR-92a-3p expression is crucial for Sc-mediated induction of active spermatogenesis at puberty and regulation of male fertility.

In this study, we used full-sib families to investigate the association between growth and gonad development during first sexual maturation of M. nipponense. We found that male GSI was significantly negatively correlated with growth traits (p < 0.01) and there were no significant correlations between female GSI (Gonadosomatic index) and growth traits (p > 0.05). HSI (Hepatopancreas index) in both males and females showed no significant correlations with growth traits (p > 0.05). We furthermore investigated the association between the specific allele of Mn-CTS L1 polymorphism and gonad development and growth traits. In total, 35 mutation loci were screened and 16 high-quality single-nucleotide polymorphisms (SNPs) loci were obtained after validation. Four and two SNPs proved to be strongly associated with all growth traits in female and male M. nipponense separately, among which A+118T might be a candidate SNP positively associated with large growth traits. Two and one SNPs were screened, respectively, in males and females to associate with GSI, while three SNPs were detected to associate with female HSI, among which A+1379C may be applied as a potential molecular marker for gene-assisted selection to improve both reproduction speed and growth traits in M. nipponense.

Follicle stimulating hormone (FSH) is produced by the pituitary gland in a coordinated hypothalamic-pituitary-gonadal (HPG) axis event, plays important roles in reproduction and germ cell development during different phases of reproductive development (fetal, neonatal, puberty, and adult life), and is consequently essential for fertility. FSH is a heterodimeric glycoprotein hormone of two dissociable subunits, α and β. The FSH β-subunit (FSHβ) function starts upon coupling to its specific receptor: follicle-stimulating hormone receptor (FSHR). FSHRs are localized mainly on the surface of target cells on the testis and ovary (granulosa and Sertoli cells) and have recently been found in testicular stem cells and extra-gonadal tissue. Several reproduction disorders are associated with absent or low FSH secretion, with mutation of the FSH β-subunit or the FSH receptor, and/or its signaling pathways. However, the influence of FSH on germ cells is still poorly understood; some studies have suggested that this hormone also plays a determinant role in the self-renewal of germinative cells and acts to increase undifferentiated spermatogonia proliferation. In addition, in vitro, together with other factors, it assists the process of differentiation of primordial germ cells (PGCLCs) into gametes (oocyte-like and SSCLCs). In this review, we describe relevant research on the influence of FSH on spermatogenesis and folliculogenesis, mainly in the germ cell of humans and other species. The possible roles of FSH in germ cell generation in vitro are also presented.

Follicle Stimulating Hormone (FSH) acts via FSH-Receptor (FSH-R) by employing cAMP as the dominant secondary messenger in testicular Sertoli cells (Sc) to support spermatogenesis. Binding of FSH to FSH-R, results the recruitment of the intracellular GTP binding proteins, either stimulatory Gαs or inhibitory Gαi that in turn regulate cAMP production in Sc. The cytosolic concentration of cAMP being generated by FSH-R thereafter critically determines the downstream fate of the FSH signalling. The pleiotropic action of FSH due to differential cAMP output during functional maturation of Sc has been well studied. However, the developmental and cellular regulation of the Gα proteins associated with FSH-R is poorly understood in Sc. In the present study, we report the differential transcriptional modulation of the Gα subunit genes by FSH mediated cAMP signalling in neonatal and pubertal rat Sc. Our data suggested that unlike in neonatal Sc, both the basal and FSH/forskolin induced expression of Gαs, Gαi-1, Gαi-2 and Gαi-3 transcripts was significantly (p

IntroductionMaturation in seawater-adapted (smoltified) male Atlantic salmon is undesirable yet frequently reported in fish weighing up to 1 kg reared under intensive conditions in land-based facilities. Although the photoperiod regulates both smoltification and maturation, the optimal post-smoltification regimen for the prevention of maturation is unclear.MethodsIn this study, mixed-sex Atlantic salmon weighing 95 g were exposed to three different photoperiod regimes: continuous daylength, gradually decreasing daylength, and short-to-long daylength after the induction of smoltification by the “winter signal” (12 h:12 h light:dark). Fish were maintained under these conditions in triplicate for 18 weeks in a brackish water flow-through system at 12°C and with a salinity of 20 ppt. This initial phase was followed by a grow-out period (1 kg–2.5 kg) in seawater (32-ppt salinity) at 13°C for 11 weeks, with exposure to decreasing daylength. Throughout the 29-week study, body condition, gonad development, and morphological traits were assessed. Additionally, during exposure to brackish water, serum 11-ketotestosterone (11-KT) levels were quantified, and the testes were examined histologically. Upon termination of the study, the maturation rate was determined.ResultsThis study exclusively detected maturation among male salmon. Under continuous light exposure, the number of fish initiating maturity steadily increased from week 8 and continued to increase in the subsequent samplings. In the short-to-long daylength group, a subset of male fish showed elevated 11-KT levels at week 14, although their gonadal development and morphological changes were not evident until week 18. Male fish exposed to decreasing daylength showed no substantial increase in 11-KT levels, although a few fish exhibited advanced gonad development by week 18. At the end of the trial, markedly lower percentages of maturing and fully mature male fish were observed among those fish previously exposed to decreasing daylength. The maturation rates at study termination were 44.4% for the short-to-long daylength group, 29.4% for the continuous daylength group, and 4.3% for the decreasing daylength group.DiscussionThese results show that photoperiod can be utilized to regulate maturation in male Atlantic salmon. In addition, decreasing the photoperiod after smoltification seems to limit early sexual maturation without compromising body size development. Thus, decreasing the photoperiod could be utilized to limit maturation in the production of post-smolt salmon or salmon in land-based facilities.

RNA N6-melthyladenosine (m6A) can play an important role in regulation of various biological processes. Chicken ovary development is closely related to egg laying performance, which is a process primarily controlled by complex gene regulations. In this study, transcriptome-wide m6A methylation of the Wuhua yellow-feathered chicken ovaries before and after sexual maturation was profiled to identify the potential molecular mechanisms underlying chicken ovary development. The results indicated that m6A levels of mRNAs were altered dramatically during sexual maturity. A total of 1,476 differential m6A peaks were found between these two stages with 662 significantly upregulated methylation peaks and 814 downregulated methylation peaks after sexual maturation. A positive correlation was observed between the m6A peaks and gene expression levels, indicating that m6A may play an important role in regulation of chicken ovary development. Functional enrichment analysis indicated that apoptosis related pathways could be the key molecular regulatory pathway underlying the poor reproductive performance of Wuhua yellow-feathered chicken. Overall, the various pathways and corresponding candidate genes identified here could be useful to facilitate molecular design breeding for improving egg production performance in Chinese local chicken breed, and it might also contribute to the genetic resource protection of valuable avian species. [ABSTRACT FROM AUTHOR]

Aim: We aimed to evaluate aspects of pubertal development to identify the most reliable clinical sign of pubertal onset in males. Methods: We performed a mini review of the literature. Results: In 1951 Reynolds and Wines categorised pubic hair growth and genital development in five stages by visual inspection. Today the Tanner scale is used to assess the five stages of pubertal development, The second genital stage, characterised by enlargement of the scrotum defines pubertal onset in males. Testicular volume may be evaluated by using a calliper or by ultrasound scan. The Prader orchidometer, described in 1966, offers a method for evaluating testicular growth by palpation. Pubertal onset is commonly defined as testicular volume >3 or ≥4 mL. The development of sensitive laboratory methods has enabled studies analysing hormonal activity in the hypothalamus‐pituitary‐gonadal axis. We review the relationships between physical and hormonal signs of puberty. We also discuss the results of studies assessing different aspects of pubertal development with a focus on identifying the most reliable clinical sign of pubertal onset in males. Conclusion: A substantial amount of evidence supports testicular volume of 3 mL as the most reliable clinical sign of male pubertal onset. [ABSTRACT FROM AUTHOR]

The warming and acidification of surface waters as predicted by the IPCC leads aquatic species to face major multifaceted changes in their environment. Although teleosts have efficient regulatory systems to cope with these changes, such changes clearly have the potential to impact their physiological functions. Hence, it is crucial to estimate the ability of teleost fishes to cope with multi-stresses to predict how they will deal with future environments. In this context, we investigated the joint effect of warming and acidification on three-spined stickleback (Gasterosteus aculeatus) from the juvenile stage to adulthood, focusing on parameters linked to growth, sexual maturation, and reproduction. Juvenile sticklebacks were split in 2 climate scenarios: a "Current" scenario corresponding to the current seasonal physico-chemical parameters of the water of the "Rade de Brest" in France, and a "RCP8.5" scenario with a warming of 3 °C and an acidification of 0.4 pH units. After 7 months, fish in the RCP8.5 scenario reached the same size and mass as those in the Current scenario, but they needed greater amounts of food to reach satiety. Furthermore, the mortality rate over the experiment was higher in the RCP8.5 scenario. Muscle lipid content, an indicator of energy reserves, was lower in females in the RCP8.5 scenario, suggesting an increased need for energy to maintain homeostasis and other physiological functions or a divergence in energy allocation strategy. Moreover, females exhibited lower sexual maturation and egg quality under the RCP8.5 scenario, which could have contributed to the lower fertilisation rate observed. Males were more resilient to the RCP8.5 scenario, exhibiting only a trend for lower kidney somatic index scores. Altogether, these results suggest a delay and/or an inhibition of gametogenesis and maturation in fish in warmed and acidified waters. The analysis of blood sex steroid concentrations, brain gene expression profiles, and physiological indexes did not allow us to discriminate between a delay and an inhibition of maturation in the RCP8.5 scenario. Overall, these findings clearly indicate that there is a long-term global impact of combined acidification and warming on the mortality and reproductive performance of three-spined stickleback. [ABSTRACT FROM AUTHOR]

Understanding the relationship between environmental temperature and the biological traits of organisms is fundamental to inferring the potential impacts of climate change. In the case of marine poikilotherm species, seawater temperature is one of the main driving forces of biological processes, with consequences at higher levels of organization such as population and ecosystem. In this study, we analysed differences in maximum carapace width (CWmax), size at maturation, relative size at maturation, and duration of the reproductive season for the green crab (Carcinus maenas) along a temperature gradient. An extensive review of bibliographic data was performed on studies published between 1962 and 2020, gathering C. maenas data from 55 different populations, spread over 20 degrees of latitude and 14.2 °C of sea surface temperature (SST). In addition, green crab data were collected at five different lagoons and estuaries along the continental Portuguese coast. The relationship between average SST and CWmax, age of maturation, reduction of size at maturation, and duration of egg bearing was analysed to understand the role of SST in driving variation in these C. maenas characteristics across a latitudinal gradient. There was a significant relationship between SST and CWmax for males and SST and CW of females at maturation, respectively. The results extrapolate for each local projected temperature increase caused by climate change and suggest an effect on the morphometric and reproductive traits of C. maenas across regions. These changes comprise an overall reduction in C. maenas body size, an enlargement of the reproductive season, a shortening in the duration of larval developmental time, and a decrease in the relative size of crabs at maturation. Secondary consequences on the fecundity and connectivity of populations are discussed. [ABSTRACT FROM AUTHOR]

This study aimed to characterize the reproductive biology of Hyphessobrycon heterorhabdus, and its response to environmental variations in the Eastern Amazon streams. We sampled specimens every two months, between March 2019 and January 2020. The population was evaluated for sex ratio, reproductive activity, growth pattern, condition factor, size at the first sexual maturation, spawning type, and fecundity. We analyzed 180 specimens, which showed a sex ratio of 1.6 males for each female across the whole period, with 2.3 males for each female during the period of greatest reproductive activity. The peak of reproductive activity coincided with higher precipitation periods and was partially predicted by factors such as water temperature, stream discharge, dissolved oxygen, substrate complexity, and electrical conductivity. The length where 50% and 100% of population to reach sexual maturity was 18.0 and 22.0 mm for males and 19.7 and 27.0 mm for females. The oocyte diameters showed a bimodal frequency, with at least two batches of oocytes. The average fecundity of 197 oocytes. The results indicate that this species presents an opportunistic strategy, and the tactics that make up this strategy depend on variations in both the physical structure of the habitat and physicochemical aspects of the water. [ABSTRACT FROM AUTHOR]

Naidids are tiny, transparent freshwater oligochaetes, which are well known for their ability to propagate asexually. Despite the fact that sexually mature individuals and cocoons with embryos are sometimes found in nature, in long-period laboratory cultures, worms reproduce agametically only. In this paper, we showed, for the first time, the expression of Vasa, Piwi, and Pl10 homologs in mature Pristina longiseta worms with well-developed reproductive system structures and germ cells. Although the animals have been propagated asexually by paratomic fission for over 20 years in our lab, some individuals become sexualized under standard conditions for our laboratory culture and demonstrate various stages of maturation. The fully matured animals developed a complete set of sexual apparatus including spermatheca, atrium, seminal vesicles, and ovisac. They also had a clitellum and were able to form cocoons. The cues for the initiation of sexual maturation are still unknown for P. longiseta; nevertheless, our data suggest that the laboratory strain of P. longiseta maintains the ability to become fully sexually mature and to establish germline products even after a long period of agametic reproduction. On the other hand, many of the sexualized worms formed a fission zone and continued to reproduce asexually. Thus, in this species, the processes of asexual reproduction and sexual maturation do not preclude each other, and Vasa, Piwi, and Pl10 homologs are expressed in both somatic and germline tissue including the posterior growth zone, fission zone, nervous system, germline cells, and gametes. [ABSTRACT FROM AUTHOR]

Context: Age of pubertal onset has been decreasing in many countries but there have been no data on pubertal development in Chinese children over the last decade. Objective: The primary objective of the study was to evaluate the current status of sexual maturation in Chinese children and adolescents. Secondary objectives were to examine socioeconomic, lifestyle, and auxological associations with pubertal onset. Methods: In this national, cross-sectional, community-based health survey, a multistage, stratified cluster random sampling method was used to select a nationally representative sample, consisting of 231 575 children and adolescents (123 232 boys and 108 343 girls) between 2017 and 2019. Growth parameters and pubertal staging were assessed by physical examination. Results: Compared to 10 years previously, the median age of Tanner 2 breast development and menarche were similar at 9.65 years and 12.39 years respectively. However, male puberty occurred earlier with a median age of testicular volume ≥4 mL of 10.65 years. Pubertal onset did occur earlier at the extremes, with 3.3% of the girls with breast development at 6.5-6.99 years old, increasing to 5.8% by 7.5-7.99 years old. Early pubertal onset was also noted in boys, with a testicular volume ≥ 4 mL noted in 1.5% at 7.5-7.99 years, increasing to 3.5% at 8.5-8.99 years old. Obesity and overweight increased risk of developing earlier puberty relative to normal weight in both boys and girls. Conclusion: Over the past decade, pubertal development is occurring earlier in Chinese children. While the cause is multifactorial, overweight and obesity are associated with earlier puberty onset. The currently used normative pubertal data of precocious puberty may not be applicable to diagnose precocious puberty. [ABSTRACT FROM AUTHOR]

AimTo examine individual variability between perceived physical features and hormones of pubertal maturation in 9-10-year-old children as a function of sociodemographic characteristics.MethodsCross-sectional metrics of puberty were utilized from the baseline assessment of the Adolescent Brain Cognitive Development (ABCD) Study-a multi-site sample of 9-10 year-olds (n = 11,875)-and included perceived physical features via the pubertal development scale (PDS) and child salivary hormone levels (dehydroepiandrosterone and testosterone in all, and estradiol in females). Multi-level models examined the relationships among sociodemographic measures, physical features, and hormone levels. A group factor analysis (GFA) was implemented to extract latent variables of pubertal maturation that integrated both measures of perceived physical features and hormone levels.ResultsPDS summary scores indicated more males (70%) than females (31%) were prepubertal. Perceived physical features and hormone levels were significantly associated with child's weight status and income, such that more mature scores were observed among children that were overweight/obese or from households with low-income. Results from the GFA identified two latent factors that described individual differences in pubertal maturation among both females and males, with factor 1 driven by higher hormone levels, and factor 2 driven by perceived physical maturation. The correspondence between latent factor 1 scores (hormones) and latent factor 2 scores (perceived physical maturation) revealed synchronous and asynchronous relationships between hormones and concomitant physical features in this large young adolescent sample.ConclusionsSociodemographic measures were associated with both objective hormone and self-report physical measures of pubertal maturation in a large, diverse sample of 9-10 year-olds. The latent variables of pubertal maturation described a complex interplay between perceived physical changes and hormone levels that hallmark sexual maturation, which future studies can examine in relation to trajectories of brain maturation, risk/resilience to substance use, and other mental health outcomes.

BackgroundSystemic inflammation may play a role in shaping breast composition, one of the strongest risk factors for breast cancer. Pubertal development presents a critical window of breast tissue susceptibility to exogenous and endogenous factors, including pro-inflammatory markers. However, little is known about the role of systemic inflammation on adolescent breast composition and pubertal development among girls.MethodsWe investigated associations between circulating levels of inflammatory markers (e.g., interleukin-6 (IL-6), tumor necrosis factor receptor 2 (TNFR2), and C-reactive protein (CRP)) at Tanner stages 2 and 4 and breast composition at Tanner stage 4 in a cohort of 397 adolescent girls in Santiago, Chile (Growth and Obesity Cohort Study, 2006-2018). Multivariable linear models were used to examine the association between breast composition and each inflammatory marker, stratifying by Tanner stage at inflammatory marker measurement. Accelerated failure time models were used to evaluate the association between inflammatory markers concentrations at each Tanner stage and time to menarche.ResultsIn age-adjusted linear regression models, a doubling of TNFR2 at Tanner 2 was associated with a 26% (95% CI 7-48%) increase in total breast volume at Tanner 4 and a 22% (95% CI 10-32%) decrease of fibroglandular volume at Tanner 4. In multivariable models further adjusted for body fatness and other covariates, these associations were attenuated to the null. The time to menarche was 3% (95% CI 1-5%) shorter among those in the highest quartile of IL-6 at Tanner 2 relative to those in the lowest quartile in fully adjusted models. Compared to those in the lowest quartile of CRP at Tanner 4, those in the highest quartile experienced 2% (95% CI 0-3%) longer time to menarche in multivariable models.ConclusionsSystemic inflammation during puberty was not associated with breast volume or breast density at the conclusion of breast development among pubertal girls after adjusting for body fatness; however, these circulating inflammation biomarkers, specifically CRP and IL-6, may affect the timing of menarche onset.

Abstract This study aimed to characterize the reproductive biology of Hyphessobrycon heterorhabdus, and its response to environmental variations in the Eastern Amazon streams. We sampled specimens every two months, between March 2019 and January 2020. The population was evaluated for sex ratio, reproductive activity, growth pattern, condition factor, size at the first sexual maturation, spawning type, and fecundity. We analyzed 180 specimens, which showed a sex ratio of 1.6 males for each female across the whole period, with 2.3 males for each female during the period of greatest reproductive activity. The peak of reproductive activity coincided with higher precipitation periods and was partially predicted by factors such as water temperature, stream discharge, dissolved oxygen, substrate complexity, and electrical conductivity. The length where 50% and 100% of population to reach sexual maturity was 18.0 and 22.0 mm for males and 19.7 and 27.0 mm for females. The oocyte diameters showed a bimodal frequency, with at least two batches of oocytes. The average fecundity of 197 oocytes. The results indicate that this species presents an opportunistic strategy, and the tactics that make up this strategy depend on variations in both the physical structure of the habitat and physicochemical aspects of the water.

Mass-reared sterile Mexican fruit flies (Anastrepha ludens [Loew]) are released along the US–Mexico border to control fruit fly damage and spread. It is more cost effective for the mass rearing program if males mature at a younger age because they can be held for a shorter time at the facility before release. In this study, adult male Mexican fruit fly diets were tested to determine if the current diet used at the mass rearing facility promotes younger mating and optimal sperm transfer compared to other diet formulations. Hydrolyzed yeast presentation methods were examined: an agar-free dry mixture of yeast and sugar (Y+S), yeast embedded in the diet during the agar boiling process (current method used) and sifted dry on the ager gel surface. Methoprene, a juvenile hormone analog was also tested as a supplement to agar gel diets with and without yeast. A greater proportion of males fedY+S mated 1 day earlier than males fed other diets. Male mating age and diet did not significantly affect the quantity of sperm transferred; however, a non-significantly higher percentage of males fed diets with embedded yeast transferred enough sperm to fill all 3 spermathecae. The results suggest that the current diet used is optimal for mass-rearing the flies and that yeast presentation method has a significant effect on A. ludens male mating age but not on the quantity of sperm transferred to females. [ABSTRACT FROM AUTHOR]

The objective of this study was verify the best waist:height ratio (WHtR) cut-off points for the prediction of insulin resistance (IR) according to stage of sexual maturation in Brazilian adolescents. Data were analysed from 37 759 adolescents between 12 and 17 years of age, of both sexes, participating in the ERICA study on cardiovascular risk factors in adolescents (' Estudo de Riscos Cardiovasculares em Adolescentes – ERICA'). The following variables were included sex, age and sexual maturity according to the Tanner stage, waist circumference, height, WHtR, fasting insulin and fasting blood sugar so as to obtain the homeostasis model assessment-estimated insulin resistance (HOMA-IR). We constructed an Receiver Operating characteristic (ROC) curve for each group in order to determine the best WHtR cut-off points for the sample stratified by sex and stratified by sex and sexual maturation stage. The female sex corresponded to 60% of the sample, with a mean age of 14·7 years (sd ± 0·08 years) and 13·1 % had IR. The prediction of IR through the WHtR indicator was better for boys, where all the areas under the ROC curve were superior to 0·70. When stratifying by sex alone, the best WHtR cut-off points found were equal to 0·45 for girls and 0·44 for boys. When stratifying by Tanner maturation stages, the cut-off points were reduced with advancing sexual maturation in the male group, while the opposite occurred in the female group. Among Brazilian adolescents, WHtR is a good predictor of IR evaluated by HOMA-IR, but different cut-off points should be adopted according to sex and sexual maturation stage. [ABSTRACT FROM AUTHOR]

The increasing use of agrochemicals, including fertilizers and herbicides, has led to worrying metal contamination of soils and waters and raises serious questions about the effects of their transfer to different levels of the trophic web. Accumulation and biomagnification of essential (K, Na, Mg, Zn, Ca), nonessential (Sr, Hg, Rb, Ba, Se, Cd, Cr, Pb, As), and rare earth elements (REEs) were investigated in newly emerged adults of Tenebrio molitor exposed to field-admitted concentrations of a metribuzin-based herbicide and an NPK blend fertilizer. Chemical analyses were performed using inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) supported by unsupervised pattern recognition techniques. Physiological parameters such as cuticle melanization, cellular (circulating hemocytes), and humoral (phenoloxidase enzyme activity) immune responses and mass loss were tested as exposure markers in both sexes. The results showed that NPK fertilizer application is the main cause of REE accumulation in beetles over time, besides toxic elements (Sr, Hg, Cr, Rb, Ba, Ni, Al, V, U) also present in the herbicide-treated beetles. The biomagnification of Cu and Zn suggested a high potential for food web transfer in agroecosystems. Gender differences in element concentrations suggested that males and females differ in element uptake and excretion. Differences in phenotypic traits show that exposure affects metabolic pathways involving sequestration and detoxification during the transition phase from immature-to-mature beetles, triggering a redistribution of resources between sexual maturation and immune responses. Our findings highlight the importance of setting limits for metals and REEs in herbicides and fertilizers to avoid adverse effects on species that provide ecosystem services and contribute to soil health in agroecosystems. [ABSTRACT FROM AUTHOR]

BackgroundNon-participation in aetiologic studies of pubertal timing is frequent. However, little effort has been given to explore the risk and potential impact of selection bias in studies of pubertal timing.ObjectiveWe aimed to explore the risk of selection bias due to non-participation in a newly established puberty cohort.MethodsWe evaluated whether three maternal exposures chosen a priori (pre-pregnancy obesity, smoking, and alcohol drinking during pregnancy) were associated with participation, whether pubertal timing was associated with participation, and whether selection bias influenced the associations between these exposures and pubertal timing. In total, 22 439 children from the Danish National Birth Cohort born 2000-2003 were invited to the Puberty Cohort and 15 819 (70%) participated. Exposures were self-reported during pregnancy. Pubertal timing was measured using a previously validated marker, "the height difference in standard deviations" (HD:SDS), which is the difference between pubertal height and adult height, both in standard deviations. For this study, pubertal height at around 13 years in sons and around 11 years in daughters was obtained from an external database, and adult height was predicted based on parental height reported by mothers.ResultsParticipation was associated with most exposures but not with pubertal timing, measured by HD:SDS. The associations between exposures and HD:SDS were comparable for participants only and all invited for participation.ConclusionIn conclusion, the risk of selection bias in aetiologic studies on pubertal timing in the Puberty Cohort appears minimal.

In humans, nonhuman primates, and rodents, the frontal cortices exhibit grey matter thinning and dendritic spine pruning that extends into adolescence. This maturation is believed to support higher cognition but may also confer psychiatric vulnerability during adolescence. Currently, little is known about how specific cell types in the frontal cortex mature or whether puberty plays a role in the maturation of some cell types but not others. Here, we used mice to characterize the spatial topography and adolescent development of cross-corticostriatal (cSTR) neurons that project through the corpus collosum to the dorsomedial striatum. We found that apical spine density on cSTR neurons in the medial prefrontal cortex decreased significantly between late juvenile (P29) and young adult time points (P60), with females exhibiting higher spine density than males at both ages. Adult males castrated prior to puberty onset had higher spine density compared to sham controls. Adult females ovariectomized before puberty onset showed greater variance in spine density measures on cSTR cells compared to controls, but their mean spine density did not significantly differ from sham controls. Our findings reveal that these cSTR neurons, a subtype of the broader class of intratelencephalic-type neurons, exhibit significant sex differences and suggest that spine pruning on cSTR neurons is regulated by puberty in male mice.

BackgroundCadmium (Cd) is a developmental toxicant that is released into the environment during industrial processes. Previous animal studies suggest that Cd may impact the onset of puberty.ObjectivesTo determine whether Cd exposure, measured as urinary Cd concentration, was associated with ages at menarche and pubertal development.MethodsA cohort of 211 girls, ages 10-13 years at baseline, was followed for up to two years. Girls completed an interview and self-assessment of Tanner stages of breast development and pubic hair growth. They were followed monthly until menarche. Urinary Cd concentrations were measured in overnight urine specimens. Multivariable Cox regression was used to evaluate the association between urinary Cd and age at menarche and cumulative logit regression was used to evaluate the associations between urinary Cd and breast development and pubic hair growth.ResultsThe baseline geometric mean creatinine-adjusted Cd concentration was 0.22 μg/g creatinine (geometric standard deviation = 1.6) and decreased with increasing age (p-trend = 0.04). Cd levels were higher among Asian than White girls or girls of other/mixed race/ethnicity (p = 0.04). In multivariable analyses, girls with urinary Cd ≥ 0.4 μg/L were less likely to have attained menarche than girls with urinary Cd

Humans and songbirds share the key trait of vocal learning, manifested in speech and song, respectively. Striking analogies between these behaviours include that both are acquired during developmental critical periods when the brains ability for vocal learning peaks. Both behaviours show similarities in the overall architecture of their underlying brain areas, characterized by cortico-striato-thalamic loops and direct projections from cortical neurons onto brainstem motor neurons that control the vocal organs. These neural analogies extend to the molecular level, with certain song control regions sharing convergent transcriptional profiles with speech-related regions in the human brain. This evolutionary convergence offers an unprecedented opportunity to decipher the shared neurogenetic underpinnings of vocal learning. A key strength of the songbird model is that it allows for the delineation of activity-dependent transcriptional changes in the brain that are driven by learned vocal behaviour. To capitalize on this advantage, we used previously published datasets from our laboratory that correlate gene co-expression networks to features of learned vocalization within and after critical period closure to probe the functional relevance of genes implicated in language. We interrogate specific genes and cellular processes through converging lines of evidence: human-specific evolutionary changes, intelligence-related phenotypes and relevance to vocal learning gene co-expression in songbirds. This article is part of the theme issue What can animal communication teach us about human language?

Neural circuits in female rats sequentially exposed to estradiol and progesterone underlie so-called estrogen positive feedback that induce the surge release of pituitary luteinizing hormone (LH) leading to ovulation and luteinization of the corpus hemorrhagicum. It is now well-established that gonadotropin releasing hormone (GnRH) neurons express neither the reproductively critical estrogen receptor-α (ERα) nor classical progesterone receptor (PGR). Estradiol from developing ovarian follicles acts on ERα-expressing kisspeptin neurons in the rostral periventricular region of the third ventricle (RP3V) to induce PGR expression, and kisspeptin release. Circulating estradiol levels that induce positive feedback also induce neuroprogesterone (neuroP) synthesis in hypothalamic astrocytes. This local neuroP acts on kisspeptin neurons that express PGR to augment kisspeptin expression and release needed to stimulate GnRH release, triggering the LH surge. In vitro and in vivo studies demonstrate that neuroP signaling in kisspeptin neurons occurs through membrane PGR activation of Src family kinase (Src). This signaling cascade has been also implicated in PGR signaling in the arcuate nucleus of the hypothalamus, suggesting that Src may be a common mode of membrane PGR signaling. Sexual maturation requires that signaling between neuroP synthesizing astrocytes, kisspeptin and GnRH neurons be established. Prior to puberty, estradiol does not facilitate the synthesis of neuroP in hypothalamic astrocytes. During pubertal development, levels of membrane ERα increase in astrocytes coincident with an increase of PKA phosphorylation needed for neuroP synthesis. Currently, it is not clear whether these developmental changes occur in existing astrocytes or are due to a new population of astrocytes born during puberty. However, strong evidence suggests that it is the former. Blocking new cell addition during puberty attenuates the LH surge. Together these results demonstrate the importance of pubertal maturation involving hypothalamic astrocytes, estradiol-induced neuroP synthesis and membrane-initiated progesterone signaling for the CNS control of ovulation and reproduction.

Life history theory examines how characteristics of organisms, such as age and size at maturity, may vary through natural selection as evolutionary responses that optimize fitness. Here we ask how predictions of age and size at maturity differ for the three classical fitness functions-intrinsic rate of natural increase r, net reproductive rate R0, and reproductive value Vx-for semelparous species. We show that different choices of fitness functions can lead to very different predictions of species behavior. In one's efforts to understand an organism's behavior and to develop effective conservation and management policies, the choice of fitness function matters. The central ingredient of our approach is the maturation reaction norm (MRN), which describes how optimal age and size at maturation vary with growth rate or mortality rate. We develop a practical geometric construction of MRNs that allows us to include different growth functions (linear growth and nonlinear von Bertalanffy growth in length) and develop two-dimensional MRNs useful for quantifying growth-mortality trade-offs. We relate our approach to Beverton-Holt life history invariants and to the Stearns-Koella categorization of MRNs. We conclude with a detailed discussion of life history parameters for Great Lakes Chinook Salmon and demonstrate that age and size at maturity are consistent with predictions using R0 (but not r or Vx) as the underlying fitness function.

AimTo examine individual variability between perceived physical features and hormones of pubertal maturation in 9-10-year-old children as a function of sociodemographic characteristics.MethodsCross-sectional metrics of puberty were utilized from the baseline assessment of the Adolescent Brain Cognitive Development (ABCD) Study-a multi-site sample of 9-10 year-olds (n = 11,875)-and included perceived physical features via the pubertal development scale (PDS) and child salivary hormone levels (dehydroepiandrosterone and testosterone in all, and estradiol in females). Multi-level models examined the relationships among sociodemographic measures, physical features, and hormone levels. A group factor analysis (GFA) was implemented to extract latent variables of pubertal maturation that integrated both measures of perceived physical features and hormone levels.ResultsPDS summary scores indicated more males (70%) than females (31%) were prepubertal. Perceived physical features and hormone levels were significantly associated with child's weight status and income, such that more mature scores were observed among children that were overweight/obese or from households with low-income. Results from the GFA identified two latent factors that described individual differences in pubertal maturation among both females and males, with factor 1 driven by higher hormone levels, and factor 2 driven by perceived physical maturation. The correspondence between latent factor 1 scores (hormones) and latent factor 2 scores (perceived physical maturation) revealed synchronous and asynchronous relationships between hormones and concomitant physical features in this large young adolescent sample.ConclusionsSociodemographic measures were associated with both objective hormone and self-report physical measures of pubertal maturation in a large, diverse sample of 9-10 year-olds. The latent variables of pubertal maturation described a complex interplay between perceived physical changes and hormone levels that hallmark sexual maturation, which future studies can examine in relation to trajectories of brain maturation, risk/resilience to substance use, and other mental health outcomes.

Pattern of physical growth and pubertal changes among 59 girls, aged 8–15 years, diagnosed as cases of HIV on anti-retroviral therapy was cross-sectionally studied. Besides, measurement of body weight, height, and body mass index, breast development stage, presence or absence of pubic and axillary hair, and age of attainment of menarche were also noted in these subjects in the growth clinic of the department. With the advancement of age, the weight and height of HIV girls increased; however, they were lighter and shorter compared to their normal peers. 15.3% of HIV girls were short-statured and underweight. None of the study participants were found to be overweight or obese. 40.7% of HIV girls had attained menarche (mean age: 12.58 ± 1.349 years). The appearance of pubic (13.45 ± 1.64 years) and axillary hair (13.73 ± 1.41 years) occurred around 1 year later. The delayed physical growth and puberty attainment of HIV girls than their normal counterparts may be due to the influence of the disease.

BACKGROUND:Earlier age at onset of pubertal events and longer intervals between them (tempo) have been associated with increased breast cancer risk. It is unknown whether the timing and tempo of puberty are associated with adult breast density, which could mediate the increased risk. METHODS:From 1988 to 1997, girls participating in the Dietary Intervention Study in Children (DISC) were clinically assessed annually between ages 8 and 17 years for Tanner stages of breast development (thelarche) and pubic hair (pubarche), and onset of menses (menarche) was self-reported. In 2006-2008, 182 participants then aged 25-29 years had their percent dense breast volume (%DBV) measured by magnetic resonance imaging. Multivariable, linear mixed-effects regression models adjusted for reproductive factors, demographics, and body size were used to evaluate associations of age and tempo of puberty events with %DBV. RESULTS:The mean (standard deviation) and range of %DBV were 27.6 (20.5) and 0.2-86.1. Age at thelarche was negatively associated with %DBV (p trend = 0.04), while pubertal tempo between thelarche and menarche was positively associated with %DBV (p trend = 0.007). %DBV was 40% higher in women whose thelarche-to-menarche tempo was 2.9 years or longer (geometric mean (95%CI) = 21.8% (18.2-26.2%)) compared to women whose thelarche-to-menarche tempo was less than 1.6 years (geometric mean (95%CI) = 15.6% (13.9-17.5%)). CONCLUSIONS:Our results suggest that a slower pubertal tempo, i.e., greater number of months between thelarche and menarche, is associated with higher percent breast density in young women. Future research should examine whether breast density mediates the association between slower tempo and increased breast cancer risk.

Abstract Background The advent of highly-active anti-retroviral therapy (HAART) has resulted in the survival of children with Human Immunodeficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDS) into adolescence. Their prolonged survival has translated into co-morbidities like endocrine deficiencies which may manifest as growth and pubertal delay. This study aimed to determine the physical growth and sexual maturation of perinatally HIV-infected adolescent males and compare them with those of age-matched HIV-negative controls. Methods We conducted a comparative cross-sectional study of 104 perinatally HIV-infected males on HAART aged 10 to 19 years, and 104 age-matched HIV-negative males who served as controls. The subjects and controls were enrolled and assessed at a Nigerian tertiary hospital over six months. Anthropometric measurements such as weight, height, and BMI were obtained and Z scores for age were derived for weight, height, and BMI to determine physical growth using WHO AnthroPlus software. Sexual maturation was assessed using the method proposed by Marshall and Tanner. Data analysis and appropriate statistics were conducted with the Statistical Package for Social Sciences (SPSS) version 25 Chicago IL. A p-value