Pubertal Onset Research Articles

Aspartame Intake Delayed Puberty Onset in Female Offspring Rats and Girls.

The disturbance of the hypothalamic-pituitary-gonadal (HPG) axis, gut microbiota (GM) community, and short-chain fatty acids (SCFAs) is a triggering factor for pubertal onset. The study investigates the effects of the long-term intake of aspartame on puberty and GM in animals and humans. Aspartame-fed female offspring rats result in vaginal opening time prolongation, serum estrogen reduction, and serum luteinizing hormone elevation. , 60mgkg-1 aspartame treatment decreases the mRNA levels of gonadotropin-releasing hormone (GnRH), Kiss1, and G protein-coupled receptor 54 (GPR54), increases the mRNA level of RFamide-related peptide-3 (RFRP-3), and decreases the expression of GnRH neurons in the hypothalamus. Significant differences in relative bacterial abundance at the genus levels and decreased fecal SCFA levels are noted by 60mgkg-1 aspartame treatment. Among which, Escherichia-Shigella is negatively correlated with several SCFAs. In girls, high-dose aspartame consumption decreases the risk of precocious puberty. Aspartame reduces the chance of puberty occurring earlier than usual in female offspring and girls. Particularly, 60mgkg-1 aspartame-fed female offspring delays pubertal onset through the dysregulation of HPG axis and GM composition by inhibiting the Kiss1/GPR54 system and inducing the RFRP-3. An acceptable dose of aspartame should be recommended during childhood.

Integrating context in the examination of pubertal timing effects on disordered eating among Black and Latinx girls.

Earlier pubertal onset has been associated with increased disordered eating symptoms in cisgender girls. Although this finding has been replicated across studies of disordered eating, most studies have focused on white samples. The lack of studies is surprising given that early pubertal timing may impact disordered eating risk in Black and Latinx girls differently due to trends of earlier pubertal onset in these groups and increased stressors related to interpersonal and structural racism and economic marginalization. Current methods of examining pubertal timing among Black and Latinx girls may also not fully capture their experience. Contextual factors (e.g., neighborhood and school racial/ethnic composition) may influence how minoritized girls both perceive and are affected by their pubertal timing. Moreover, factors such as ethnic-racial identity development and experiences of discrimination may be important mechanisms explaining the association between pubertal timing and disordered eating risk. This paper aims to provide a brief overview of studies examining pubertal timing and disordered eating risk among Black and Latinx girls in the US and to discuss recommendations for future research that integrate contextual factors in the examination of pubertal timing and its effects. PUBLIC SIGNIFICANCE: Early pubertal timing has been associated with increased risk of disordered eating symptoms among cisgender girls; however, studies have been limited due to the use of predominantly white samples. The article provides a brief overview of findings related to pubertal timing effects among Black and Latinx girls, discusses considerations for the measurement of pubertal timing, and highlights the need for inclusion of contextual factors in future research.

Epigenetic age acceleration is associated with speed of pubertal growth but not age of pubertal onset

Using data from a longitudinal cohort of children, we examined whether epigenetic age acceleration (EAA) was associated with pubertal growth and whether these associations were mediated by adiposity. We examined associations between EAA at approximately 10 years of age with pubertal growth metrics, including age at peak height velocity (PHV), PHV, and sex steroid levels and whether these associations were mediated by measures of adiposity including body mass index (BMI) and MRI-assessed visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT). Children (n = 135) with accelerated EAA had higher PHV (β 0.018, p = 0.0008) although the effect size was small. The association between EAA and age at PHV was not significant (β − 0.0022, p = 0.067). Although EAA was associated with higher BMI (β 0.16, p = 0.0041), VAT (β 0.50, p = 0.037), and SAT (β 3.47, p = 0.0076), BMI and VAT did not mediate associations between EAA and PHV, while SAT explained 8.4% of the association. Boys with higher EAA had lower total testosterone (β − 12.03, p = 0.0014), but associations between EAA and other sex steroids were not significant, and EAA was not associated with sex steroid levels in girls. We conclude that EAA did not have strong associations with either age at onset of puberty or pubertal growth speed, although associations with growth speed were statistically significant. Studies with larger sample sizes are needed to confirm this pattern of associations.

Navigating adolescence: pubertal development in autism spectrum conditions and its relation to mental health.

Adolescence is a period of social, psychological, and physiological change, including the onset of puberty. Differential pubertal onset has been linked to a myriad of problems, including mental health problems. Therefore, we aim to investigate deviating pubertal development in autism, and whether this is more pronounced in girls than in boys. A total of 68 individuals (nASC = 34, nCOM (comparisons) = 34) aged 12 to 16years were administered test concerning pubertal development and mental health (i.e., sensory sensitivity, autistic traits, depression, anxiety, and externalizing problems). Frequentist and Bayesian ANOVA was used to examine deviations in pubertal development in ASC and possible sex effects. Regression analyses was used to test whether this asynchronicity was linked to mental health problems. Our (frequentist and Bayesian) analyses revealed earlier onset and slower development of pubertal development in ASC but we did not find any sex differences. Maturation disparity was linked to higher mental health problems in ASC, but not in COM. No sex differences in the relation with mental health outcomes was found. We found evidence for a slower development of "true" puberty in those with ASC compared to those without. Moreover, we show that disparities in pubertal development are related to mental health in ASC, suggesting a greater impact on mental health in autistic than in non-autistic teens. Longitudinal studies are necessary to elucidate important developmental trajectories in puberty in neurodiverse populations.

Prepubescent Electronic Cigarette Exposure Affects Sexual Motivation and Puberty in Female But Not Male Long-Evans Rats.

A method for delivering vaporized nicotine to animals has been developed using e-cigarette devices. The present experiment was designed to measure the effects of e-cigarette nicotine on pubertal onset and development of reproductive behavior in female and male Long-Evans rats. Rats received daily 10-min sessions of electronic-cigarette vaporized nicotine (5% Virginia Tobacco JUUL Pods) or room air in a whole-body exposure chamber (postnatal day 28-31). Pubertal onset was monitored daily (ie, vaginal opening in females, preputial separation in males). Two weeks later, rats were tested for sexual motivation using the partner-preference paradigm, whereby subjects were given the opportunity to approach either a sexual partner or a same-sex social partner. Four weeks later, partner preference was assessed again, 10 min after rats were re-exposed to their same prepubertal treatment. We found that prepubescent electronic-cigarette vaporized nicotine disrupted puberty and sexual motivation in female but not male rats. In vaped females, vaginal opening was delayed and less time was spent with the male stimulus compared to room-air controls. In contrast, no effect of e-cigarette vapor was observed on pubertal onset or on any measures of sexual behavior in male rats. No effects were observed in either female or male rats on the second partner-preference test. Prepubescent vaporized nicotine affected the development of reproductive physiology and behavior in female rats but not in male rats, whereas an additional acute exposure to nicotine vapor had no effect in either female or male adult rats. Given the prevalence of increasingly younger users, more animal research is needed to explore the effects of e-cigarette smoking on multiple developmental systems including reproductive physiology and behavior. This model could be useful in exploring multiple behavioral and physiological endpoints in both sexes. Adjustments to the duration of exposure and control conditions will be necessary for future experiments to best model human use.

Timing of menarche and pubertal growth patterns using the QEPS growth model.

To explore the timing of menarche, postmenarcheal growth, and to investigate the impact of various variables on menarcheal age and postmenarcheal and pubertal growth. This longitudinal community population-based study analyzed pubertal growth and menarcheal age in 793 healthy term-born Swedish girls, a subset of the GrowUp1990Gothenburg cohort. The timing of menarche and postmenarcheal growth was related to variables from the Quadratic-Exponential-Pubertal-Stop (QEPS) growth model, birth characteristics, and parental height. Multivariable models were constructed for clinical milestones; at birth, age 7 years, pubertal growth onset, and midpuberty. Menarche aligned with 71.6% (18.8) of the QEPS model's specific pubertal growth function, at a mean age of 13.0 (1.3) years, ranging from 8.2 to 17.2 years. Postmenarcheal growth averaged 8.0 (4.9) cm, varying widely from 0.2 to 31.1 cm, decreasing with later menarche. Significant factors associated with menarcheal age included height at 7 years, childhood body-mass index, parental height, and QEPS-derived pubertal growth variables. Multivariable models demonstrated increasing explanatory power for each milestone, explaining 1% of the variance in menarcheal age at birth, 8% at age 7 years, 44% at onset of pubertal growth, and 45% at midpuberty. This study underscores the strong link between pubertal growth and age at menarche. Data available at start of puberty explain 44% of the variation in menarcheal age, apparent on average 3.2 years before menarche. In addition, the study shows a previously seldom noticed wide variation in postmenarcheal height gain from 0.2 to 31.1 cm.

Increased IGFBP Proteolysis, IGF-I Bioavailability, and Pappalysin Levels in Children With Prader-Willi Syndrome.

Prader-Willi syndrome (PWS) is associated with impaired growth hormone (GH) secretion and decreased insulin-like growth factor (IGF)-I levels. Pappalysins (PAPP-A, PAPP-A2) and stanniocalcins (STC-1, STC-2) regulate IGF binding-protein (IGFBP) cleavage and IGF bioavailability, but their implication in PWS is unknown. We determined serum levels of PAPP-As and STCs in association with IGF axis components in prepubertal and pubertal patients with PWS, also analyzing the effect of GH treatment. Forty children and adolescents with PWS and 120 sex- and age-matched controls were included. The effect of GH was evaluated at 6 months of treatment in 11 children. Children with PWS had lower levels of total IGF-I, total and intact IGFBP-3, acid-labile subunit, intact IGFBP-4, and STC-1, and they had higher concentrations of free IGF-I, IGFBP-5, and PAPP-A. Patients with PWS after pubertal onset had decreased total IGF-I, total and intact IGFBP-3, and intact IGFBP-4 levels, and had increased total IGFBP-4, and STCs concentrations. GH treatment increased total IGF-I, total and intact IGFBP-3, and intact IGFBP-4, with no changes in PAPP-As, STCs, and free IGF-I levels. Standardized height correlated directly with intact IGFBP-3 and inversely with PAPP-As and the free/total IGF-I ratio. The increase in PAPP-A could be involved in increased IGFBP proteolysis, promoting IGF-I bioavailability in children with PWS. Further studies are needed to establish the relationship between growth, GH resistance, and changes in the IGF axis during development and after GH treatment in these patients.

The transcription factor VAX1 in VIP neurons of the suprachiasmatic nucleus impacts circadian rhythm generation, depressive-like behavior, and the reproductive axis in a sex-specific manner in mice.

The suprachiasmatic nucleus (SCN) within the hypothalamus is a key brain structure required to relay light information to the body and synchronize cell and tissue level rhythms and hormone release. Specific subpopulations of SCN neurons, defined by their peptide expression, regulate defined SCN output. Here we focus on the vasoactive intestinal peptide (VIP) expressing neurons of the SCN. SCN VIP neurons are known to regulate circadian rhythms and reproductive function. To specifically study SCN VIP neurons, we generated a novel knock out mouse line by conditionally deleting the SCN enriched transcription factor, Ventral Anterior Homeobox 1 (Vax1), in VIP neurons (Vax1Vip; Vax1fl/fl:VipCre). We found that Vax1Vip females presented with lengthened estrous cycles, reduced circulating estrogen, and increased depressive-like behavior. Further, Vax1Vip males and females presented with a shortened circadian period in locomotor activity and ex vivo SCN circadian period. On a molecular level, the shortening of the SCN period was driven, at least partially, by a direct regulatory role of VAX1 on the circadian clock genes Bmal1 and Per2. Interestingly, Vax1Vip females presented with increased expression of arginine vasopressin (Avp) in the paraventricular nucleus, which resulted in increased circulating corticosterone. SCN VIP and AVP neurons regulate the reproductive gonadotropin-releasing hormone (GnRH) and kisspeptin neurons. To determine how the reproductive neuroendocrine network was impacted in Vax1Vip mice, we assessed GnRH sensitivity to a kisspeptin challenge in vivo. We found that GnRH neurons in Vax1Vip females, but not males, had an increased sensitivity to kisspeptin, leading to increased luteinizing hormone release. Interestingly, Vax1Vip males showed a small, but significant increase in total sperm and a modest delay in pubertal onset. Both male and female Vax1Vip mice were fertile and generated litters comparable in size and frequency to controls. Together, these data identify VAX1 in SCN VIP neurons as a neurological overlap between circadian timekeeping, female reproduction, and depressive-like symptoms in mice, and provide novel insight into the role of SCN VIP neurons.

Molecular Analysis of the First Reported Hereditary Lymphedema-distichiasis Case in Bangladesh

Lymphedema–distichiasis syndrome (LD, OMIM 153400) is hereditary primary lymphedema with autosomal dominant nature of inheritance and variable expression. LD is characterized by late childhood or pubertal onset of lower limb lymphedema and an aberrant second row of eyelashes (distichiasis) arising from the meibomian glands. Among the molecular reasons behind this condition are the mutations in the FOXC2 gene, a forkhead transcription factor, that plays a role in the formation of lymphatic and vascular systems. In this study, we report the first case of LD from Bangladesh with classical lymphedema–distichiasis syndrome with an eight-base-pair deletion in the FOXC2 gene. ClinVar accession code for this deletion is RCV000007679.3. FOXC2 protein is 501 amino acids long. This deletion of 8 bp (ACGCCGCC) causes frameshift of codons after amino acid number 304. The frameshift creates an altered truncated protein with 154 new amino acids after codon 304. We assume that these changes in the protein may affect its function contributing to the disease manifestations. Further research may confirm these assumptions. J. Bangladesh Acad. Sci. 47(2); 205-213: December 2023

Pubertal Development Pattern in HIV-Infected Girls in Port Harcourt, Southern Nigeria

Background: Unidentified and untreated pubertal abnormalities in HIV-infected girls may result in adverse psychosocial consequences as well as a reduced final adult height. The aim of the study was to determine the pubertal development pattern in HIV-infected girls receiving care in two tertiary hospitals in Port Harcourt, Southern Nigeria.
 Materials and Methods: This was a comparative cross-sectional study involving 90 HIV-infected girls aged 10-18 years and 90 age, sex and socio-economic class matched non-HIV-infected girls.
 Results: The mean age of pubertal onset in HIV-infected girls was 11.57±1.05 which was significantly higher than the mean age of 10.78±0.69 seen in the non-HIV-infected group (ꭓ 2= 2.667, p=0.011). Sixty three (70%) of HIV-infected females had commenced puberty (Tanner stage 2 or above for breast development) compared to 83 (92.2%) of non-HIV-infected females. (χ2=16.277, p=0.003). Forty per cent (40%) of HIV-infected girls had attained menarche (40%) as against 52.2% in the comparison group but this difference was not statistically significant (χ2=2.705, p=0.100). There was a higher prevalence of pubertal delay in HIV-infected girls (6.7%) compared to non-HIV-infected girls (1.1%).
 Conclusion: The mean age of Pubertal onset was significantly later in HIV-infected girls compared to non-HIV-infected. This could have negative implications for psychosocial and reproductive health in HIV-infected girls.

Pubertal attainment and Leydig cell function following pediatric hematopoietic stem cell transplantation: a three-decade longitudinal assessment.

Impaired testosterone secretion is a frequent sequela following hematopoietic stem cell transplantation (HSCT) in pediatrics, but long-term longitudinal trendlines of clinical and biochemical findings are still scanty. Monocentric, retrospective analysis. Male patients transplanted <18 years between 1992 and 2021, surviving ≥2 years after HSCT and showing, upon enrollment, clinical and biochemical signs consistent with pubertal onset and progression were included. Clinical and biochemical data collected every 6-12 months were recorded. Of 130 patients enrolled, 56% were prepubertal, while 44% were peri-/postpubertal upon HSCT. Overall, 44% showed spontaneous progression into puberty and normal gonadal profile, while the remaining experienced pubertal arrest (1%), isolated increase of FSH (19%), compensated (23%) or overt (13%) hypergonadotropic hypogonadism. Post-pubertal testicular volume (TV) was statistically smaller among patients still pre-pubertal upon HSCT (p 0.049), whereas no differences were recorded in adult testosterone levels. LH and testosterone levels showed a specular trend between 20 and 30 years, as a progressive decrease in sexual steroids was associated with a compensatory increase of the luteinizing hormone. A variable degree of gonadal dysfunction was reported in 85%, 51%, 32% and 0% of patients following total body irradiation- (TBI), busulfan-, cyclophosphamide- and treosulfan-based regimens, respectively. TBI and busulfan cohorts were associated with the lowest probability of gonadal event-free course (p<0.0001), while it achieved 100% following treosulfan. A statistically greater gonadotoxicity was detected after busulfan than treosulfan (p 0.024). Chemo-only regimens were associated with statistically larger TV (p <0.001), higher testosterone (p 0.008) and lower gonadotropin levels (p <0.001) than TBI. Accordingly, the latter was associated with a 2-fold increase in the risk of gonadal failure compared to busulfan (OR 2.34, CI 1.08-8.40), whereas being pre-pubertal upon HSCT was associated with a reduced risk (OR 0.15, CI 0.08-0.30). a) patients pre-pubertal upon HSCT showed a reduced risk of testicular endocrine dysfunction, despite smaller adult TV; b) patients showed downwards trend in testosterone levels after full pubertal attainment, despite a compensatory increase in LH; c) treosulfan was associated to a statistically lower occurrence of hypogonadism than busulfan, with a trend towards larger TV, higher testosterone levels and lower gonadotropins.

Sleep deprivation alters pubertal timing in humans and rats: the role of the gut microbiome.

Evidence implied that sleeping duration is associated with the timing of puberty and that sleep deprivation triggers early pubertal onset in adolescents. Sleep deprivation can affect metabolic changes and gut microbiota composition. This study investigated the effects of sleep deprivation on pubertal onset and gut microbiota composition in animal models and a human cohort. This study comprised 459 boys and 959 girls from the Taiwan Pubertal Longitudinal Study. Sleep duration was evaluated using the self-report Pittsburgh Sleep Quality Index questionnaire. Early sexual maturation was defined by pediatric endocrinologist assessments. Mediation analyses were done to examine the association between sleep parameters, obesity, and early sexual maturation. Besides, Sprague Dawley juvenile rats were exposed to 4 weeks of chronic sleep deprivation. Vaginal opening (VO) and preputial separation (PS) were observed every morning to determine pubertal onset in female and male rats. The sleep-deprived juvenile rats in the sleep-deprived-female (SDF) and sleep-deprived-male (SDM) groups experienced delayed VO (mean VO days: 33 days in control; 35 days in SDF; p-value < 0.05) and PS (mean PS days: 42 days in control; 45 days in SDM; p-value < 0.05), respectively. Relative to their non-sleep-deprived counterparts, the sleep-deprived juvenile rats exhibited lower body weight and body fat percentage. Significant differences in relative bacterial abundance at genus levels and decreased fecal short-chain-fatty-acid levels were identified in both the SDF and SDM groups. In the human cohort, insufficient sleep increased the risk of early sexual maturation, particularly in girls (OR, 1.44; 95% CI: 1.09 to 1.89; p-value < 0.01). Insufficient sleep also indirectly affected early sexual maturation in girls, with obesity serving as the mediator. Overall, sleep deprivation altered the timing of puberty in both animal and human models but in different directions. In the rat model, sleep deprivation delayed the pubertal onset in juvenile rats through gut dysbiosis and metabolic changes, leading to a low body weight and body fat percentage. In the human model, sleep deprivation led to fat accumulation, causing obesity in girls, which increased the risk of early puberty.

The association between sleep and early pubertal development in Chinese children: a school population-based cross-sectional study.

There is an increasing tendency toward early pubertal development, and sleep might be related to pubertal onset. We aimed to investigate the association of sleep duration and bedtime with early pubertal development. This was a cross-sectional study of 8,007 children (53.6% boys) from Qufu city, Shandong province and Zhongshan city, Guangdong province, China. Data on sleep duration and bedtime were obtained by questionnaire. Early pubertal development was the primary outcome and it was evaluated by the pediatrician according to Tanner staging. Logistic regression models were used to separately examine the association between sleep duration or bedtime and early pubertal development, controlling body mass index (BMI), dietary pattern, soft drink, feeding pattern and mother's BMI. In boys, short sleep duration was strongly related to early pubertal development [OR (95%CI): 4.26 (1.30, 13.94)], and this association was intensified after adjusted BMI, dietary pattern, soft drink, feeding pattern and mother's BMI. In girls, OR (95%CI) was 1.62 (1.04, 2.51), and increased after controlling BMI. Bedtime was associated with early pubertal development on weekdays [OR (95%CI): 6.39 (1.54, 26.45) in boys and 1.93 (1.23, 3.05) in girls], but not on weekends [OR (95%CI): 2.49 (0.61, 10.21) in boys; 1.31 (0.76, 2.25) in girls]. This study underscores the positive association between the risk of early pubertal development and insufficient sleep duration and late bedtime.

DNA methylation sites in early adulthood characterised by pubertal timing and development: a twin study

BackgroundPuberty is a highly heritable and variable trait, with environmental factors having a role in its eventual timing and development. Early and late pubertal onset are both associated with various diseases developing later in life, and epigenetic characterisation of pubertal timing and development could lead to important insights. Blood DNA methylation, reacting to both genotype and environment, has been associated with puberty; however, such studies are relatively scarce. We investigated peripheral blood DNA methylation profiles (using Illumina 450 K and EPIC platforms) of 1539 young adult Finnish twins associated with pubertal development scale (PDS) at ages 12 and 14 as well as pubertal age (PA).ResultsFixed effect meta-analysis of the two platforms on 347,521 CpGs in common identified 58 CpG sites associated (p < 1 × 10−5) with either PDS or PA. All four CpGs associated with PA and 45 CpGs associated with PDS were sex-specific. Thirteen CpGs had a high heritability (h2: 0.51–0.98), while one CpG site (mapped to GET4) had a high shared environmental component accounting for 68% of the overall variance in methylation at the site. Utilising twin discordance analysis, we found 6 CpG sites (5 associated with PDS and 1 with PA) that had an environmentally driven association with puberty. Furthermore, genes with PDS- or PA-associated CpGs were consistently linked to various developmental processes and diseases such as breast, prostate and ovarian cancer, while methylation quantitative trait loci of associated CpG sites were enriched in immune pathways developing during puberty.ConclusionsBy identifying puberty-associated DNA methylation sites and examining the effects of sex, environment and genetics, we shed light on the intricate interplay between environment and genetics in the context of puberty. Through our comprehensive analysis, we not only deepen the understanding of the significance of both genetic and environmental factors in the complex processes of puberty and its timing, but also gain insights into potential links with disease risks.

Adult height in girls with central precocious puberty without gonadotropin-releasing hormone agonist treatment: a retrospective case-control study.

The primary aim of this study was to investigate the final adult height (FAH) of girls diagnosed with central precocious puberty (CPP) who were untreated. We retrospectively analyzed the medical records of 36 girls diagnosed with CPP between 8 and 9 years of age who did not receive treatment, and 206 girls diagnosed with CPP within the same age range who received gonadotropin-releasing hormone (GnRH) agonist treatment. Midparental height (MPH), predicted adult height (PAH) obtained using height and bone age (BA) at the time of diagnosis (PAH for BA), and PAH obtained using the Bayley-Pinneau method (PAH by BP) were calculated. Additionally, height at the time of growth completion was compared with the predicted height. The FAHs were 160.71±4.56 cm in the untreated group and 159.31±4.26 cm in the treated group. In the untreated group, the FAH was 0.99±4.50 cm shorter than the MPH but 4.29±3.33 cm and 3.46±3.93 cm greater than the PAH for BA and PAH by BP, respectively. In children diagnosed with CPP between 8 and 9 years of age who were untreated, FAH was greater than PAH for BA and PAH by BP at the time of diagnosis, indicating that the prognosis of FAH was not poor. Therefore, for girls diagnosed with CPP, it is recommended to consider various conditions, such as pubertal onset, height at diagnosis, BA, peak luteinizing hormone level, predicted height, and speed of puberty, when deciding whether to administer GnRH agonists.

Fibroblast Growth Factor 21 Has a Diverse Role in Energetic and Reproductive Physiological Functions of Female Beef Cattle.

Fibroblast growth factor 21 (FGF21) has been identified in multiple mammalian species as a molecular marker of energy metabolism while also providing negative feedback to the gonads. However, the role of FGF21 in regulating the energetic and reproductive physiology of beef heifers and cows has yet to be characterized. Herein, we investigated the temporal concentrations of FGF21 in female beef cattle from the prepubertal period to early lactation. Circulating concentrations of FGF21, non-esterified fatty acids, plasma urea nitrogen, glucose, and progesterone were assessed. Ultrasonography was employed to determine the onset of puberty and resumption of postpartum ovarian cyclicity as well as to measure backfat thickness. Finally, cows and calves underwent the weigh-suckle-weigh technique to estimate rate of milk production. We have revealed that FGF21 has an expansive role in the physiology of female beef cattle, including pubertal onset, adaptation to nutritional transition, rate of body weight gain, circulating markers of metabolism, and rate of milk production. In conclusion, FGF21 plays a role in physiological functions in beef cattle that can be applied to advance the understanding of basic scientific processes governing the nutritional regulation of reproductive function but also provides a novel means for beef cattle producers to select parameters of financial interest.

SAT608 Gonadotrope-specific Deletion Of Icer Results In Increased Lh Pulsatility But Reduced Fsh Levels In Mice

Abstract Disclosure: N.P. Boris: None. S.A. Pereira: None. G.A. Stamatiades: None. K.N. Hausken: None. H. Kim: None. R.S. Carroll: None. U.B. Kaiser: None. Background: The hypothalamic-pituitary-gonadal (HPG) axis is regulated by pulsatile secretion of hypothalamic GnRH, which acts on anterior pituitary gonadotropes to control synthesis and secretion of LH and FSH. High and low GnRH pulse frequencies preferentially stimulate Lhb and Fshb expression, respectively, through mechanisms that are not completely understood. The mouse Fshb gene promoter contains a half-AP-1/half-cAMP response element (CRE) motif; we have shown previously that this element is bound by CRE-binding protein (Creb) in vitro to increase expression in response to low GnRH pulse frequencies, but is antagonized by inducible cAMP early repressor (Icer) at higher GnRH pulse frequencies, resulting in a lower level of Fshb transcription. In this study, we aimed to identify the role of Icer in gonadotropin regulation in vivo in mice. We hypothesized that gonadotrope-specific deletion of Icer may influence pubertal timing and fertility due to an increase in Fshb expression. Methods and Results: Gonadotrope-specific deletion of Icer (GnrhrGRIC/+/Icerfl/fl; Icer KO) and control (Icerfl/fl) mice were generated, and pubertal and reproductive phenotypes were evaluated. There was no difference in body weight or in pubertal timing, evaluated by age of preputial separation in males and by vaginal opening and first estrus in females. In post-pubertal male mice, neither basal LH and FSH levels nor the LH or FSH response to acute GnRH stimulation were significantly different in Icer KO mice, compared to littermate Icerfl/fl controls. Male Icer KO mice 14 days post-gonadectomy (GDX) had significantly more LH pulses within a three-hour period than controls (Icer KO 5.83 ± 0.4 pulses vs Icerfl/fl 4.66 ± 0.3 pulses; p=0.049), but no differences in basal LH or LH pulse amplitude. Interestingly, serum FSH levels were significantly lower in Icer KO mice compared to Icerfl/fl controls 2 days post-GDX (Icer KO 20.0 ± 1.0 vs Icerfl/fl 26.0 ± 0.8; p=0.003) and 7 days post-GDX (Icer KO 18.0 ± 0.4 vs Icerfl/fl 22.5 ± 0.8, p=0.002). There were no significant differences in pituitary Fshb, Lhb, or Gnrhr mRNA levels between Icer KO and Icerfl/fl control mice 14 days post-GDX. Conclusions: Deletion of Icer from pituitary gonadotropes in mice did not affect body weight or timing of pubertal onset. However, in GDX male mice, LH pulse frequency was increased, whereas the post-GDX increase in serum FSH levels was blunted, in Icer KO mice compared to controls. These findings support a role for Icer in both LH and FSH regulation in vivo and highlight the importance of extending in vitro observations to in vivo models. Presentation: Saturday, June 17, 2023

THU206 Constitutional Delay Of Puberty And Idiopathic Hypogonadotropic Hypogonadism: Differential Contributions Of Common Genetic Variants

Abstract Disclosure: M.F. Lippincott: None. E. Schafer: None. A.A. Hindman: None. R. Brauner: None. A. Delaney: None. K. McElreavey: None. J.E. Hall: None. J.N. Hirschhorn: None. M.R. Palmert: None. S.B. Seminara: None. R.M. Salem: None. Y. Chan: None. Introduction: Disorders of pubertal timing include self-limited constitutional delay of puberty (CDP) and longer lasting idiopathic hypogonadotropic hypogonadism (IHH). Both conditions have strong genetic influences. We sought to determine if common genetic variants that influence pubertal timing contribute to CDP and IHH. Hypothesis: IHH and CDP can sometimes be caused by the accumulation of common genetic variants that delay pubertal onset. Therefore, compared to controls, patients with CDP and IHH have higher polygenic risk scores (PRS) based on genome-wide association studies (GWAS) for pubertal timing. Methods: All research and data-sharing were conducted with participant/guardian consent and institutional ethical approval. We defined CDP as puberty starting between 12 and 18 y in girls and between 13.5 and 18 y in boys and IHH as low sex steroids and non-elevated gonadotropins at ≥18 y, both with no cause identified on standard clinical evaluation. We genotyped CDP cases (n=106) on the Illumina Infinium OmniExpress Exome 8-1v6 platform and retrieved array-matched control data from dbGaP (n=9,222). IHH cases (n=713) and controls from the Schizophrenia Psychiatric GWAS (n=1,868) were genotyped on the Infinium PsychArray. After data harmonization, quality control, and principal components analysis were performed on combined sets, genotype imputation was performed on all unrelated individuals of European ancestry using the Michigan Imputation Server. We downloaded summary statistics for: 1) GWAS meta-analysis for age at menarche (AAM), 2) multi-trait GWAS for male pubertal hallmarks, and 3) a negative control using GWAS for basal cell carcinoma (BCC). We calculated and compared PRS between cases and controls using PRS-CS and PRSice2, with the first 10 ancestral principal components and sex as covariates. We also performed sex-stratified analyses. Results: Both the CDP and the IHH cohorts had significantly higher PRS for male pubertal hallmarks compared to controls, but the difference was smaller for IHH (CDP Cohen’s d=0.59, p=2×10-10; IHH d=0.13, p=0.007). The CDP cohort also had a significantly higher PRS for AAM compared to controls (d=0.83, p=8×10-20), but the IHH cohort did not (d=0.08, p=0.06). Of note, sex-specific PRS provided greater discrimination between CDP cases and controls in stratified analyses of the corresponding sex (AAM in females: d=1.1, p=4×10-11; AAM in males d=0.72, p=8×10-11; male hallmarks in females: d=0.52, p=0.001; male hallmarks in males: d=0.63, p=2×10-8). No significant differences were observed between cases and controls for BCC PRS. Conclusions: Common genetic variants that influence pubertal timing in the general population contribute strongly to the genetics of CDP, with some sex-specificity, but only weakly to IHH. These findings support the hypothesis that the common-variant genetics of CDP and IHH are largely distinct. Presentation: Thursday, June 15, 2023

THU580 A Subset Of Migrating Cells Co-express Gonadotropin Releasing Hormone And Prokineticin Receptor 2 During Embryonic Development

Abstract Disclosure: A.E. Danku: None. C.F. Elias: None. A subset of migrating cells co-express gonadotropin releasing hormone and prokineticin receptor 2 during embryonic development Antoinette Danku and Carol F Elias. Neuroscience Graduate Program and Department of Molecular &amp; Integrative Physiology, University to Michigan. Reproductive vitality in humans is strongly influenced by developmental foundations. The successful migration of GnRH cells and the pulsatile secretion of gonadotropin releasing hormone (GnRH) drives pubertal onset and dictates long-term fertility outcomes. During development, GnRH neurons migrate from the nasal placode to the basal forebrain to reach their destination in the medial preoptic area (MPOA). Aberrant GnRH migration causes redirection of axonal projections to atypical brain regions and dysregulated GnRH secretion. Disruption of GnRH neuronal function causes infertility or reproductive dysfunction. These etiologies are grouped as isolated gonadotropin deficiencies (IGD). Kallmann’s syndrome (KS) is a pediatric IGD that manifests as anosmia and hormonal dysfunction that can result in pubertal delay or infertility. Children with KS often have mutations in prokineticin 2 (Prok2) or the cognate receptor (ProkR2).Prok2 and ProkR2 are required for the formation of the olfactory bulb in rodents and humans. Loss-of-function mutations in these genes also disrupts GnRH cell migration, but whether the activation of ProkR2 regulates the guidance of GnRH neurons to their final destination has not been defined. Previous studies suggested that GnRH and ProkR2 are expressed in distinct cells, but how the prokineticin system may alter GnRH migration is largely unknown. To gain insights into the underlying mechanisms associated with ProkR2-GnRH interaction and migration, we conducted single nuclei RNA sequencing in nasal-forebrain junction of embryos at embryonic day 16 (E16) and fluorescent in situ hybridization in three developmental time points: E14, E16, and E18 for validation and spatial evaluation. Using these methods, we were able to isolate GnRH and ProkR2 cells and sort their cell types into clusters. While these cells differ in their expression profiles, they both express genes associated with migration at E16. Our findings suggest that ProkR2 cells in the nasal-forebrain junction migrate along with GnRH cells. Additionally, a subset of these migrating cells co-express ProkR2 and GnRH mRNA. Further studies are needed to determine whether this subset of cells take on specialized roles in GnRH cell migration and maturation. Presentation: Thursday, June 15, 2023

Comparison of female rat reproductive effects of pubertal versus adult exposure to known endocrine disruptors.

A prevailing challenge when testing chemicals for their potential to cause female reproductive toxicity is the lack of appropriate toxicological test methods. We hypothesized that starting a 28-day in vivo toxicity study already at weaning, instead of in adulthood, would increase the sensitivity to detect endocrine disruptors due to the possibility of including assessment of pubertal onset. We compared the sensitivity of two rat studies using pubertal or adult exposure. We exposed the rats to two well-known human endocrine disruptors, the estrogen diethylstilbestrol (DES; 0.003, 0.012, 0.048 mg/kg bw/day) and the steroid synthesis inhibitor ketoconazole (KTZ; 3, 12, 48 mg/kg bw/day). Specifically, we addressed the impact on established endocrine-sensitive endpoints including day of vaginal opening (VO), estrous cyclicity, weights of reproductive organs and ovarian histology. After 28 days of exposure, starting either at weaning or at 9 weeks of age, DES exposure altered estrous cyclicity, reduced ovary weight as well as number of antral follicles and corpora lutea. By starting exposure at weaning, we could detect advanced day of VO in DES-exposed animals despite a lower body weight. Some endpoints were affected mainly with adult exposure, as DES increased liver weights in adulthood only. For KTZ, no effects were seen on time of VO, but adrenal and liver weights were increased in both exposure scenarios, and adult KTZ exposure also stimulated ovarian follicle growth. At first glance, this would indicate that a pubertal exposure scenario would be preferrable as timing of VO may serve as sensitive indicator of endocrine disruption by estrogenic mode of action. However, a higher sensitivity for other endocrine targets may be seen starting exposure in adulthood. Overall, starting a 28-day study at weaning with inclusion of VO assessment would mainly be recommended for substances showing estrogenic potential e.g., in vitro, whereas for other substances an adult exposure scenario may be recommended.