Maturation of luteinizing hormone (gonadotropin-releasing hormone) secretion across puberty: evidence for altered regulation in obese peripubertal girls

The effect of obesity on the GnRH stimulation test in girls with idiopathic central precocious puberty

The gonadotropin-releasing hormone (GnRH) stimulation test is essential for diagnosing idiopathic central precocious puberty (ICPP). Research provided that luteinizing hormone (LH) levels during the test are lower in overweight and obese girls. This study aims to establish diagnostic cut-off values in the GnRH stimulation test specifically for overweight and obese girls with ICPP. Retrospective data from 925 girls diagnosed with ICPP or premature thelarche (PT) who underwent GnRH testing were analyzed. Patients were categorized into normal weight (NW) and overweight/obese (OW) groups based on Body Mass Index Standard Deviation Score (BMI-SDS), with BMI-SDS ≥ 1 indicating OW. Only patients with Tanner stage 2 or 3 breast development were included. The mean age at diagnosis was 7.9 ± 1.1 years in ICPP and 6.4 ± 1.4 years in PT. Among the patients, 455 (49.2%) were OW. In the OW-ICPP group, the peak LH cut-off was 3.56 IU/L (AUC:0.733; sensitivity:69.2%, specificity:64%), and the peak LH/FSH ratio was 0.29 (AUC:0.828; sensitivity:77.1%, specificity:76.3%). For NW patients, the peak LH cut-off was 4.75 IU/L (AUC:0.809; sensitivity:77.1%, specificity:70.7%), and the peak LH/FSH ratio was 0.3 (AUC:0.926; sensitivity: 86.3%, specificity: 86%). In the peak LH cut-off model, the multivariate analysis identified BMI-SDS as a significant negative predictor (OR:0.585, 95%CI: 0.477-0.717, p < 0.001), showing a strong inverse relationship. Similarly, in the peak LH/FSH ratio model, BMI-SDS remained a significant negative predictor (OR: 0.744, 95% CI: 0.614-0.902, p < 0.001).

CONCLUSION

In this study, gonadotropin responses during the GnRH stimulation test were lower in overweight and obese girls with Tanner stage 2 and 3 ICPP compared to standard thresholds. It is important to utilize the GnRH test alongside clinical findings when diagnosing these patients, as responses below standard values do not rule out precocious puberty. This highlights the need for tailored diagnostic criteria to ensure timely and accurate diagnosis in this population.

WHAT IS KNOWN

• Obesity is a risk factor for early puberty.

WHAT IS NEW

• In girls with idiopathic central precocious puberty, obesity leads to lower values in the GnRH stimulation test compared to normal ranges. This may result in missed diagnoses, emphasizing the need to evaluate cases thoroughly with clinical data.

Shared Pathophysiological Mechanisms and Genetic Factors in Early Menarche and Polycystic Ovary Syndrome

Early age at menarche (early AAM) and polycystic ovary syndrome (PCOS) are reproductive and metabolic disorders with overlapping pathophysiological and genetic features. Epidemiological studies suggest a link between these two conditions, both of which are characterized by dysregulation of the neuroendocrine pathways that control pulsatile gonadotropin-releasing hormone secretion, thus affecting gonadotropin release, particularly luteinizing hormone secretion. A common pathophysiology involving positive energy balance and abnormal metabolic status is evident in both disorders. Genetic and epigenetic factors influence the onset of puberty and reproductive outcomes. Genome-wide association studies have identified common genetic variants associated with AAM and PCOS, particularly in genes related to the neuroendocrine axis (e.g., FSHB) and obesity (e.g., FTO). In addition, high-throughput sequencing has revealed rare loss-of-function variants in the DLK1 gene in women with central precocious puberty (CPP), early menarche, and PCOS, who experienced adverse metabolic outcomes in adulthood. This review explores the shared pathophysiological mechanisms between CPP/early AAM and PCOS, examines potential genetic and epigenetic factors that may link these neuroendocrine reproductive conditions, and offers insights into future research and treatment strategies. Understanding these connections may provide new targets for therapeutic interventions and improve outcomes for individuals with these reproductive disorders.

Polycystic Ovary Syndrome in Adolescents

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrinologic disorder that is characterized by oligomenorrhea or amenorrhea and signs of hyperandrogenism. The cause of PCOS remains unknown, but the syndrome is associated with insulin resistance that in turn leads to hyperandrogenism. An accurate and prompt diagnosis of PCOS is important to understanding an adolescent's risk. In adolescents, both oligoovulation and hyperandrogenism are needed for the diagnosis of PCOS and ultrasound is not recommended. Lifelong health consequences of PCOS are significant and include obesity, diabetes, metabolic syndrome, and anovulatory infertility. The symptoms of PCOS can be disturbing to an adolescent girl.

Sex and Sleep Disruption as Contributing Factors in Alzheimer's Disease

Alzheimer's disease (AD) affects more women than men, with women throughout the menopausal transition potentially being the most under researched and at-risk group. Sleep disruptions, which are an established risk factor for AD, increase in prevalence with normal aging and are exacerbated in women during menopause. Sex differences showing more disrupted sleep patterns and increased AD pathology in women and female animal models have been established in literature, with much emphasis placed on loss of circulating gonadal hormones with age. Interestingly, increases in gonadotropins such as follicle stimulating hormone are emerging to be a major contributor to AD pathogenesis and may also play a role in sleep disruption, perhaps in combination with other lesser studied hormones. Several sleep influencing regions of the brain appear to be affected early in AD progression and some may exhibit sexual dimorphisms that may contribute to increased sleep disruptions in women with age. Additionally, some of the most common sleep disorders, as well as multiple health conditions that impair sleep quality, are more prevalent and more severe in women. These conditions are often comorbid with AD and have bi-directional relationships that contribute synergistically to cognitive decline and neuropathology. The association during aging of increased sleep disruption and sleep disorders, dramatic hormonal changes during and after menopause, and increased AD pathology may be interacting and contributing factors that lead to the increased number of women living with AD.

Overactivation of GnRH neurons is sufficient to trigger polycystic ovary syndrome-like traits in female mice

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder leading to anovulatory infertility. Abnormalities in the central neuroendocrine system governed by gonadotropin-releasing hormone (GnRH) neurons might be related to ovarian dysfunction in PCOS, although the link in this disordered brain-to-ovary communication remains unclear. Here, we manipulated GnRH neurons using chemogenetics in adult female mice to unveil whether chronic overaction of these neurons would trigger PCOS-like hormonal and reproductive impairments.

METHODS

We used adult Gnrh1cre female mice to selectively target and express the designer receptors exclusively activated by designer drugs (DREADD)-based chemogenetic tool hM3D(Gq) in hypophysiotropic GnRH neurons. Chronic chemogenetic activation protocol was carried out with clozapine N-oxide (CNO) i.p. injections every 48 h over a month. We evaluated the reproductive and hormonal profile before, during, and two months after chemogenetic manipulations.

FINDINGS

We discovered that the overactivation of GnRH neurons was sufficient to disrupt reproductive cycles, promote hyperandrogenism, and induce ovarian dysfunction. These PCOS features were detected with a long-lasting neuroendocrine dysfunction through abnormally high luteinizing hormone (LH) pulse secretion. Additionally, the GnRH-R blockade prevented the establishment of long-term neuroendocrine dysfunction and androgen excess in these animals.

INTERPRETATION

Taken together, our results show that hyperactivity of hypothalamic GnRH neurons is a major driver of reproductive and hormonal impairments in PCOS and suggest that antagonizing the aberrant GnRH signaling could be an efficient therapeutic venue for the treatment of PCOS.

FUNDING

European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement n◦ 725149).

Association Between Markers of Adiposity During Childhood and Puberty Onset in Latino Girls

CONTEXT

Prepubertal adiposity is associated with earlier puberty. It is unclear when this association starts, if all adiposity markers are similarly associated, and whether all pubertal milestones are similarly affected.

OBJECTIVE

To evaluate the association between different adiposity markers during childhood and the timing of different pubertal milestones in Latino girls.

DESIGN, SETTING, AND PARTICIPANTS

Longitudinal follow-up of 539 female participants of the Chilean Growth and Obesity Cohort recruited from childcare centers (mean age 3.5 years) from the southeast area of Santiago, Chile. Participants were singletons born between 2002 and 2003 within the normal birthweight range. Since 2006, a trained dietitian measured weight, height, waist circumference (WC) and skinfolds to estimate body mass index (BMI) Centers for Disease Control and Prevention percentiles, central obesity, percentage of fat mass (%FM), and fat mass index (FMI, fat mass/height2).

MAIN OUTCOME

Since 2009, sexual maturation was assessed every 6 months to assess age at (1) thelarche, (2) pubarche, (3) menarche, and (4) peak height velocity (PHV).

RESULTS

At thelarche, 12.5% were obese and 2% had central obesity. The median age of pubarche, menarche, and PHV were all associated with markers of adiposity at different time points during childhood whereas thelarche only with %FM and FMI. Adiposity clusters models showed that children with trajectories of high WC, %FM, and FMI during childhood were related with earlier thelarche, pubarche, menarche, and PHV but BMI trajectories only with menarche and PHV.

CONCLUSIONS

Higher WC, %FM, and FMI were associated with earlier age at thelarche, pubarche, menarche, and PHV. The effect of BMI was less consistent.

Oxidative stress and antioxidant imbalance in ovulation disorder in patients with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disease that is characterized by oligo-ovulation or anovulation, hyperandrogenism, and polycystic ovaries observed using ultrasound with high clinical heterogeneity. At present, the etiology of PCOS is not clear but is thought to be related to genetic, metabolic, endocrine and environmental factors. Hyperandrogenism interacts with insulin resistance and overweight/obesity, forming a vicious cycle of mutual promotion and participating in the occurrence and progression of PCOS. Oxidative stress (OS) refers to the imbalance between the oxidation system and antioxidation system in the human body, which is associated with the occurrence and development of various diseases. Recent studies have shown that OS may be closely related to ovulation disorders in PCOS, and antioxidants can improve the oxidative stress state of PCOS. However, previous studies did not examine the effect of the interaction between OS and hyperandrogenism, insulin resistance or overweight/obesity on ovulation disorders in PCOS. This article reviews the interaction between OS and hyperandrogenism, insulin resistance and overweight/obesity; the effects of OS, hyperandrogenism, insulin resistance and overweight/obesity on ovulation disorders in PCOS; and the application of antioxidants in PCOS.

The role of gonadotropin-releasing hormone neurons in polycystic ovary syndrome

Given the critical central role of gonadotropin-releasing hormone (GnRH) neurons in fertility, it is not surprising that the GnRH neural network is implicated in the pathology of polycystic ovary syndrome (PCOS), the most common cause of anovulatory infertility. Although many symptoms of PCOS relate most proximately to ovarian dysfunction, the central reproductive neuroendocrine system ultimately drives ovarian function through its regulation of anterior pituitary gonadotropin release. The typical cyclical changes in frequency of GnRH release are often absent in women with PCOS, resulting in a persistent high-frequency drive promoting gonadotropin changes (i.e., relatively high luteinizing hormone and relatively low follicle-stimulating hormone concentrations) that contribute to ovarian hyperandrogenemia and ovulatory dysfunction. However, the specific mechanisms underpinning GnRH neuron dysfunction in PCOS remain unclear. Here, we summarize several preclinical and clinical studies that explore the causes of aberrant GnRH secretion in PCOS and the role of disordered GnRH secretion in PCOS pathophysiology.

Polycystic Ovary Syndrome and the Neuroendocrine Consequences of Androgen Excess

Polycystic ovary syndrome (PCOS) is a major endocrine disorder strongly associated with androgen excess and frequently leading to female infertility. Although classically considered an ovarian disease, altered neuroendocrine control of gonadotropin-releasing hormone (GnRH) neurons in the brain and abnormal gonadotropin secretion may underpin PCOS presentation. Defective regulation of GnRH pulse generation in PCOS promotes high luteinizing hormone (LH) pulsatile secretion, which in turn overstimulates ovarian androgen production. Early and emerging evidence from preclinical models suggests that maternal androgen excess programs abnormalities in developing neuroendocrine circuits that are associated with PCOS pathology, and that these abnormalities are sustained by postpubertal elevation of endogenous androgen levels. This article will discuss experimental evidence, from the clinic and in preclinical animal models, that has significantly contributed to our understanding of how androgen excess influences the assembly and maintenance of neuroendocrine impairments in the female brain. Abnormal central gamma-aminobutyric acid (GABA) signaling has been identified in both patients and preclinical models as a possible link between androgen excess and elevated GnRH/LH secretion. Enhanced GABAergic innervation and drive to GnRH neurons is suspected to contribute to the pathogenesis and early manifestation of neuroendocrine derangement in PCOS. Accordingly, this article also provides an overview of GABA regulation of GnRH neuron function from prenatal development to adulthood to discuss possible avenues for future discovery research and therapeutic interventions. © 2022 American Physiological Society. Compr Physiol 12:3347-3369, 2022.

An Approach to the Evaluation and Management of the Obese Child With Early Puberty

With the declining age at onset of puberty and increasing prevalence of childhood obesity, early breast development in young obese girls has become a more frequent occurrence. Here, we examine available literature to answer a series of questions regarding how obesity impacts the evaluation and management of precocious puberty. We focus on girls as the literature is more robust, but include boys where literature permits. Suggestions include: (1) Age cutoffs for evaluation of precocious puberty should not differ substantially from those used for nonobese children. Obese girls with confirmed thelarche should be evaluated for gonadotropin-dependent, central precocious puberty (CPP) to determine if further investigation or treatment is warranted. (2) Basal luteinizing hormone (LH) levels remain a recommended first-line test. However, if stimulation testing is utilized, there is a theoretical possibility that the lower peak LH responses seen in obesity could lead to a false negative result. (3) Advanced bone age (BA) is common among obese girls even without early puberty; hence its diagnostic utility is limited. (4) Obesity does not eliminate the need for magnetic resonance imaging in girls with true CPP. Age and clinical features should determine who warrants neuroimaging. (5) BA can be used to predict adult height in obese girls with CPP to inform counseling around treatment. (6) Use of gonadotropin-releasing hormone analogues (GnRHa) leads to increased adult height in obese girls. (7) Obesity should not limit GnRHa use as these agents do not worsen weight status in obese girls with CPP.

Profile of gene expression changes during estrodiol-17β-induced feminization in the Takifugu rubripes brain

Background

As the critical tissue of the central nervous system, the brain has been found to be involved in gonad development. Previous studies have suggested that gonadal fate may be affected by the brain. Identifying brain-specific molecular changes that occur during estrodiol-17β (E₂) -induced feminization is crucial to our understanding of the molecular control of sex differentiation by the brains of fish.

Results

In this study, the differential transcriptomic responses of the Takifugu rubripes larvae brain were compared after E₂ treatment for 55 days. Our results showed that 514 genes were differentially expressed between E₂-treated-XX (E-XX) and Control-XX (C-XX) T. rubripes, while 362 genes were differentially expressed between E₂-treated-XY (E-XY) and Control-XY (C-XY). For example, the expression of cyp19a1b, gnrh1 and pgr was significantly up-regulated, while st, sl, tshβ, prl and pit-1, which belong to the growth hormone/prolactin family, were significantly down-regulated after E₂ treatment, in both sexes. The arntl1, bhlbe, nr1d2, per1b, per3, cry1, cipc and ciart genes, which are involved in the circadian rhythm, were also found to be altered. Differentially expressed genes (DEGs), which were identified between E-XX and C-XX, were significantly enriched in neuroactive ligand-receptor interaction, arachidonic acid metabolism, cytokine-cytokine receptor interaction and the calcium signaling pathway. The DEGs that were identified between E-XY and C-XY were significantly enriched in tyrosine metabolism, phenylalanine metabolism, arachidonic acid metabolism and linoleic acid metabolism.

Conclusion

A number of genes and pathways were identified in the brain of E₂-treated T. rubripes larvae by RNA-seq. It provided the opportunity for further study on the possible involvement of networks in the brain-pituitary-gonadal axis in sex differentiation in T. rubripes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-08158-0.

Unravelling Polycystic Ovary Syndrome and Its Comorbidities

Polycystic ovary syndrome (PCOS) is a chronic multisystem endocrine disorder that affects women of reproductive age. In the ovary, the dynamic balance between dormant and growing follicles that culminates in ovulation becomes dysfunctional in the presence of excessive androgen production (ovarian/adrenal/peripheral). Moreover, hyperandrogenicity in pregnancy affects fetal development in utero and is linked to maternal pregnancy complications. Hormonal imbalance, ovarian dysfunction, and central obesity often emerge in these patients during adolescence. Once disordered physiological changes develop in PCOS, a vicious cycle ensues, leading to reproductive, metabolic, and psychological comorbidities. With the alarming increase of the number of young adults with a high degree of obesity in Korea, the prevalence of PCOS has also considerably increased. Timely and accurate screening, multicomponent healthy lifestyle modifications for both patients and family members, and comprehensive medical interventions based on international evidence-based guidelines are essential for curtailing PCOS and its comorbidities.

Longitudinal Investigation of Pubertal Milestones and Hormones as a Function of Body Fat in Girls

CONTEXT

Epidemiologic studies have demonstrated that overweight/obese girls (OW/OB) undergo thelarche and menarche earlier than normal weight girls (NW). There have been no longitudinal studies to specifically investigate how body weight/fat affects both clinical and biochemical pubertal markers in girls.

OBJECTIVE

To investigate the effect of total body fat on reproductive hormones and on the maturation of estrogen-sensitive tissues during puberty in girls.

METHODS

Ninety girls (36 OW/OB, 54 NW), aged 8.2 to 14.7 years, completed 2.8 ± 1.7 study visits over 4 years. Visits included dual-energy x-ray absorptiometry to calculate total body fat (TBF), Tanner staging, breast ultrasound for morphological staging (BMORPH; A-E), pelvic ultrasound, hormone tests, and assessment of menarchal status. The effect of TBF on pubertal markers was determined using a mixed, multistate, or Cox proportional hazards model, controlling for baseline BMORPH.

RESULTS

NW were older than OW/OB (11.3 vs 10.2 years, P < .01) at baseline and had more advanced BMORPH (P < .01). Luteinizing hormone, estradiol, and ovarian and uterine volumes increased with time with no effect of TBF. There was a time × TBF interaction for follicle-stimulating hormone, inhibin B, estrone, total and free testosterone, and androstenedione: Levels were initially similar, but after 1 year, levels increased in girls with higher TBF, plateaued in girls with midrange TBF, and decreased in girls with lower TBF. Girls with higher TBF progressed through BMORPH stage D more slowly but achieved menarche earlier than girls with lower TBF.

CONCLUSION

In late puberty, girls with higher TBF demonstrate differences in standard hormonal and clinical markers of puberty. Investigation of the underlying causes and clinical consequences of these differences in girls with higher TBF deserves further study.

Sleep and Puberty

In the 1970's, Boyar and colleagues made the seminal observation that during the early stages of puberty, there is a sleep-specific augmentation of pulsatile luteinizing hormone (LH) secretion. Building on this tantalizing association between sleep and the re-awakening of the neuro-reproductive axis, a number of investigators have since mapped the dynamic relationship between sleep and reproductive hormones across the pubertal transition. In this review, we focus on the complex, reciprocal relationship between sleep and reproductive hormones during adolescence as well as the potential effects of melatonin and orexin on gonadotropin-releasing hormone (GnRH) activity in children with chronic insomnia and narcolepsy, respectively. Given the important interaction between the reproductive and somatotropic axes during puberty, we end with a discussion of sleep and growth hormone (GH) secretion in children.

Polycystic Ovary Syndrome: Ontogeny in Adolescence

The pathophysiology of symptomatic polycystic ovary syndrome (PCOS) often unfolds across puberty, but the ontogeny of PCOS is difficult to study because, in general, its pathophysiology is well entrenched before the diagnosis can be confirmed. However, the study of high-risk groups (daughters of women with PCOS, girls with premature pubarche, and girls with obesity) can offer insight in this regard. Available data support the hypothesis that the pubertal development of PCOS involves various combinations of genetic predisposition, intrauterine programming, hyperinsulinism, and numerous other abnormalities that provoke reproductive symptoms (eg, hyperandrogenism, ovulatory dysfunction) in response to the pubertal increase in gonadotropin secretion.

Subacute cadmium exposure disrupts the hypothalamic-pituitary-gonadal axis, leading to polycystic ovarian syndrome and premature ovarian failure features in female rats

Cadmium (Cd), a toxic heavy metal, is a known endocrine disruptor that is associated with reproductive complications. However, few studies have explored the effects of Cd exposure on features of polycystic ovary syndrome (PCOS) and premature ovary failure (POF). In this study, we assessed whether doses found in workers occupationally exposed to Cd and subacute exposure result in hypothalamic-pituitary-gonadal (HPG) axis and other irregularities. We administered CdCl₂ to female rats (100 ppm in drinking water for 30 days) and then assessed Cd levels in the blood, HPG axis and uterus. Metabolic features, HPG axis function, reproductive tract (RT) morphophysiology, inflammation, oxidative stress (OS), and fibrosis were evaluated. Cd exposure increased Cd levels in the serum, HPG axis, and uterus. Cd rats displayed metabolic impairments, such as a reduction in adiposity, dyslipidemia, and insulin resistance (IR). Cd exposure also caused improper functioning in the HPG. Specifically, Cd exposure caused irregular estrous cyclicity, abnormal hypothalamic gene expression (upregulated - Kiss1, AR and mTOR; downregulated - Kiss1R, LepR and TNF-α), high LH levels, low AMH levels and abnormal ovarian follicular development, coupled with a reduction in ovarian reserve and antral follicle number was observed, suggesting ovarian depletion. Further, Cd exposure caused a reduction in corpora lutea (CL) and granulosa layer thickness together with an increase in cystic/atretic follicles. In addition, Cd exposure caused RT inflammation, OS and fibrosis. Finally, strong positive correlations were observed between serum, RT Cd levels, IR, dyslipidemia and estrous cycle length, cystic, atretic follicles, LH levels, and RT inflammation. Thus, these data suggest that subacute Cd exposure using doses found in workers occupationally exposed to Cd disrupt the HPG axis function, leading to PCOS and POF features and other abnormalities in female rats.

Central Ceramide Signaling Mediates Obesity-Induced Precocious Puberty

Childhood obesity, especially in girls, is frequently bound to earlier puberty, which is linked to higher disease burden later in life. The mechanisms underlying this association remain elusive. Here we show that brain ceramides participate in the control of female puberty and contribute to its alteration in early-onset obesity in rats. Postnatal overweight caused earlier puberty and increased hypothalamic ceramide content, while pharmacological activation of ceramide synthesis mimicked the pubertal advancement caused by obesity, specifically in females. Conversely, central blockade of de novo ceramide synthesis delayed puberty and prevented the effects of the puberty-activating signal, kisspeptin. This phenomenon seemingly involves a circuit encompassing the paraventricular nucleus (PVN) and ovarian sympathetic innervation. Early-onset obesity enhanced PVN expression of SPTLC1, a key enzyme for ceramide synthesis, and advanced the maturation of the ovarian noradrenergic system. In turn, obesity-induced pubertal precocity was reversed by virogenetic suppression of SPTLC1 in the PVN. Our data unveil a pathway, linking kisspeptin, PVN ceramides, and sympathetic ovarian innervation, as key for obesity-induced pubertal precocity.

Prenatal Androgenization Alters the Development of GnRH Neuron and Preoptic Area RNA Transcripts in Female Mice

Polycystic ovary syndrome (PCOS) is the most common form of infertility in women. The causes of PCOS are not yet understood and both genetics and early-life exposure have been considered as candidates. With regard to the latter, circulating androgens are elevated in mid-late gestation in women with PCOS, potentially exposing offspring to elevated androgens in utero; daughters of women with PCOS are at increased risk for developing this disorder. Consistent with these clinical observations, prenatal androgenization (PNA) of several species recapitulates many phenotypes observed in PCOS. There is increasing evidence that symptoms associated with PCOS, including elevated luteinizing hormone (LH) (and presumably gonadotropin-releasing hormone [GnRH]) pulse frequency emerge during the pubertal transition. We utilized translating ribosome affinity purification coupled with ribonucleic acid (RNA) sequencing to examine GnRH neuron messenger RNAs from prepubertal (3 weeks) and adult female control and PNA mice. Prominent in GnRH neurons were transcripts associated with protein synthesis and cellular energetics, in particular oxidative phosphorylation. The GnRH neuron transcript profile was affected more by the transition from prepuberty to adulthood than by PNA treatment; however, PNA did change the developmental trajectory of GnRH neurons. This included families of transcripts related to both protein synthesis and oxidative phosphorylation, which were more prevalent in adults than in prepubertal mice but were blunted in PNA adults. These findings suggest that prenatal androgen exposure can program alterations in the translatome of GnRH neurons, providing a mechanism independent of changes in the genetic code for altered expression.

Neuropilin-1 expression in GnRH neurons regulates prepubertal weight gain and sexual attraction

Hypothalamic neurons expressing gonadotropin-releasing hormone (GnRH), the "master molecule" regulating reproduction and fertility, migrate from their birthplace in the nose to their destination using a system of guidance cues, which include the semaphorins and their receptors, the neuropilins and plexins, among others. Here, we show that selectively deleting neuropilin-1 in new GnRH neurons enhances their survival and migration, resulting in excess neurons in the hypothalamus and in their unusual accumulation in the accessory olfactory bulb, as well as an acceleration of mature patterns of activity. In female mice, these alterations result in early prepubertal weight gain, premature attraction to male odors, and precocious puberty. Our findings suggest that rather than being influenced by peripheral energy state, GnRH neurons themselves, through neuropilin-semaphorin signaling, might engineer the timing of puberty by regulating peripheral adiposity and behavioral switches, thus acting as a bridge between the reproductive and metabolic axes.

High-refined carbohydrate diet leads to polycystic ovary syndrome-like features and reduced ovarian reserve in female rats

Obesity is associated with several female reproductive complications, such as polycystic ovary syndrome (PCOS). The exact mechanism of this relationship remains unclear. Few previous studies using diet containing refined carbohydrate (HCD) leading to obesity have been performed and it is unclear if HCD is linked with reproductive dysfunctions. In this investigation, we assessed whether subchronic HCD exposure results in reproductive and other irregularities. Female rats were fed with HCD for 15 days and metabolic outcomes and reproductive tract morphophysiology were assessed. We further assessed reproductive tract inflammation, oxidative stress (OS) and fibrosis. HCD rats displayed metabolic impairments, such as an increase in body weight/adiposity, adipocyte hypertrophic, abnormal lipid profile, glucose tolerance and insulin resistance (IR) and hyperleptinemia. Improper functioning of the HCD reproductive tract was observed. Specifically, irregular estrous cyclicity, high LH levels and abnormal ovarian morphology coupled with reduction in primordial and primary follicle numbers was observed, suggesting ovarian reserve depletion. Improper follicular development and a reduction in antral follicles, corpora lutea and granulosa layer area together with an increase in cystic follicles were apparent. Uterine atrophy and reduction in endometrial gland (GE) number was observed in HCD rats. Reproductive tract inflammation, OS and fibrosis were seen in HCD rats. Further, strong positive correlations were observed between body weight/adiposity and IR with estrous cycle length, cystic follicles, ovarian reserve, GE and other abnormalities. Thus, these data suggest that the subchronic HCD exposure led to PCOS-like features, impaired ovarian reserve, GE number, and other reproductive abnormalities in female rats.

Pathological pulses in PCOS

Polycystic ovary syndrome (PCOS) is a highly prevalent endocrine disorder associated with hyperandrogenism and anovulation. Although a spectrum disorder, many women with PCOS exhibit elevated luteinizing hormone (LH) pulse frequency and an elevated LH to follicle stimulating hormone ratio. This aberrant pattern of gonadotrophin signalling drives many of the downstream ovarian features of PCOS, including increased androgen synthesis, and indicates neuroendocrine impairments upstream. Decreased responsiveness to gonadal steroid hormone negative feedback in PCOS patients points toward dysfunction within the gonadotropin-releasing hormone (GnRH) neuronal network in the brain. Excessive androgen exposure during development or over pubertal onset can recapitulate the neuroendocrine pathology of PCOS in pre-clinical models, and these models have been fundamental in beginning to pick apart the specific central mechanisms involved. This mini-review will briefly describe the pathology of PCOS associated with high frequency GnRH/LH pulses and then highlight what is currently known, and yet to be discovered, about the central mechanisms involved.

Association between overweight or obesity and the risk for childhood asthma and wheeze: An updated meta-analysis on 18 articles and 73 252 children

BACKGROUND

Overweight or obesity is increasingly recognized as a possible risk factor for childhood asthma.

OBJECTIVES

We aimed to meta-analyse the association between overweight or obesity and the risk for childhood asthma and wheeze and meanwhile explore potential causes of between-study heterogeneity.

METHODS

Literature search, study selection, and data extraction were performed independently and in duplicate. Data were analysed by STATA software.

RESULTS

Eighteen articles and 73 252 children were analysed. In overall analyses, there was a significant association between overweight or obesity and the risk for childhood asthma (odds ratio [OR] = 1.30; 95% confidence interval [CI], 1.23-1.39; P < 0.001) and wheeze (OR = 1.90; 95% CI, 1.38-2.63; P < 0.001), with none/marginal publication bias as revealed by the Egger test (P = 0.938/0.038), respectively. Subgroup analyses showed that children with obesity (OR = 1.40; 95% CI, 1.29-1.52) were more likely to have asthma than children with overweight (OR = 1.22; 95% CI, 1.14-1.31), and in children with overweight or obesity, girls (OR = 1.34; 95% CI, 1.16-1.56) were more likely to have asthma than boys (OR = 1.27; 95% CI, 1.15-1.40).

CONCLUSIONS

Our findings indicate that overweight or obesity is a significant risk factor for childhood asthma and wheeze and in children with overweight or obesity, the risk is more evident in girls than in boys.

Early breast development in overweight girls: does estrogen made by adipose tissue play a role?

Background

Girls who are overweight/obese (OB) develop breast tissue but do not undergo menarche (the first menstrual period) significantly earlier than girls of normal weight (NW). It has been proposed that estrogen synthesized by adipose tissue may be contributory, yet OB do not have higher serum estrogen levels than NW matched on breast stage. We hypothesized that estrogen synthesized locally, in mammary fat, may contribute to breast development. This hypothesis would predict that breast development would be more advanced than other estrogen-sensitive tissues as a function of obesity and body fat.

Methods

80 pre-menarchal girls (26 OB, 54 NW), aged 8.2–14.7 yrs, underwent dual-energy x-ray absorptiometry to calculate percent body fat (%BF), Tanner staging of the breast, breast ultrasound for morphological staging, trans-abdominal pelvic ultrasound, hand x-ray (bone age), a blood test for reproductive hormones, and urine collection to determine the vaginal maturation index (VMI), an index of estrogen exposure in urogenital epithelial cells.

Results

When controlling for breast morphological stage determined by ultrasound, %BF was not associated with serum estrogen or gonadotropin (LH and FSH) levels or on indices of systemic estrogen action (uterine volume, endometrial thickness, bone age advancement, and VMI). Tanner breast stage did not correlate with breast morphological stage and led to misclassification of chest fatty tissue as breast tissue in some OB.

Conclusions

These studies do not support the hypothesis that estrogen derived from total body fat or local (mammary) fat contributes to breast development in overweight/obese girls.

The Relationship Between Progesterone, Sleep, and LH and FSH Secretory Dynamics in Early Postmenarchal Girls

CONTEXT

During puberty, LH pulse frequency increases during sleep; in women, LH pulse frequency slows during sleep in the early/middle follicular phase (FP) of the menstrual cycle. The origin and significance of this developmental transition are unknown.

OBJECTIVE

To determine the relationship between progesterone (P4) exposure, sleep-related slowing of LH pulses in the FP, and the intercycle FSH rise, which promotes folliculogenesis, in early postmenarchal girls.

METHODS

23 girls (gynecologic age 0.4 to 3.5 years) underwent hormone measurements and pelvic ultrasounds during two consecutive cycles and one frequent blood sampling study with concurrent polysomnography during the FP.

RESULTS

Subjects demonstrated one of four patterns during cycle 1 that represent a continuum of P4 exposure: ovulatory cycles with normal or short luteal phase lengths or anovulatory cycles ± follicle luteinization. Peak serum P4 and urine pregnanediol (Pd) in cycle 1 were inversely correlated with LH pulse frequency during sleep in the FP of cycle 2 (r = -0.5; P = 0.02 for both). The intercycle FSH rise and folliculogenesis in cycle 2 were maintained after anovulatory cycles without P4 or Pd exposure or nocturnal slowing of LH pulse frequency in the FP.

CONCLUSIONS

During late puberty, rising P4 levels from follicle luteinization and ovulation may promote a slower LH pulse frequency during sleep in the FP. However, a normal FSH rise and follicle growth can occur in the absence of P4-associated slowing. These studies therefore suggest that an immature LH secretory pattern during sleep is unlikely to contribute to menstrual irregularity in the early postmenarchal years.

Sex-Specific Association between Childhood BMI Trajectories and Asthma Phenotypes

BACKGROUND

Asthma and obesity are two common health problems in the pediatric population. Obesity is associated with several comorbidities which are of great consequence. Excess adipose tissue has been linked to asthma in a number of studies. However, little is known about childhood body mass index (BMI) trajectories and the development of asthma phenotypes.

OBJECTIVE

The current study aims to investigate the significance of BMI trajectories over childhood and the risk of asthma phenotypes.

METHODS

The current study is a prospective cohort of children aged 0-2 years who were followed every two years for eight years through cycles one to five in the National Longitudinal Survey of Children and Youths (NLSCY). Statistical analysis: a latent class growth modelling (LCGM) method was used to identify BMI trajectory patterns from cycles one to five. Multiple imputation (number of imputations=5) was carried out to impute children with missing values on height or weight information. Sampling weights and 1,000 bootstrap weights were used in SAS PROC SURVEYLOGISTIC to examine the association between BMI trajectory and asthma phenotypes (persistent or transient asthma) in a multivariate analysis.

RESULTS

The study consisted of 571,790 males and 549,230 females. Among them, 46% of children showed an increasing trajectory in terms of change in BMI percentile during childhood, followed by the stable-trajectory group (41%) and decreasing-trajectory group (13%). After controlling for confounding factors, females in the increasing BMI trajectory group were four times more likely to be associated with persistent asthma (OR = 4.09; 95% CI:1.04-16.15; p = 0.0442) than females in the stable BMI trajectory group. No such relationship was found in males. The BMI trajectory was not significantly associated with risk of transient asthma for either sex.

CONCLUSION

We report a female-specific association between increasing adiposity, measured by BMI, and persistent asthma.

Central Obesity, Faster Maturation, and 'PCOS' in Girls

Polycystic ovary syndrome (PCOS) development commonly starts with a mismatch between pre- and postnatal weight gain, leading to hepatovisceral fat excess. To escape from such central obesity, girls may accelerate their growth and/or maturation. This homeostatic mechanism is lost upon reaching adult height, and PCOS may ensue. Prevention and/or treatment of PCOS should aim at reducing central fat excess.

Downregulation of leptin receptor and kisspeptin/GPR54 in the murine hypothalamus contributes to male hypogonadism caused by high-fat diet-induced obesity

PURPOSE

Obesity may lead to male hypogonadism, the underlying mechanism of which remains unclear. In the present study, we established a murine model of male hypogonadism caused by high-fat diet-induced obesity to verify the following hypotheses: 1) an increased leptin level may be related to decreased secretion of GnRH in obese males, and 2) repression of kisspeptin/GPR54 in the hypothalamus, which is associated with increased leptin levels, may account for the decreased secretion of GnRH and be involved in secondary hypogonadism (SH) in obese males.

METHODS

Male mice were fed high-fat diet for 19 weeks and divided by body weight gain into diet-induced obesity (DIO) and diet-induced obesity resistant (DIO-R) group. The effect of obesity on the reproductive organs in male mice was observed by measuring sperm count and spermatozoid motility, relative to testis and epididymis weight, testosterone levels, and pathologic changes. Leptin, testosterone, estrogen, and LH in serum were detected by ELISA method. Leptin receptor (Ob-R), Kiss1, GPR54, and GnRH mRNA were measured by real-time PCR in the hypothalamus. Expression of kisspeptin and Ob-R protein was determined by Western blotting. Expression of GnRH and GPR54 protein was determined by immunohistochemical analysis.

RESULTS

We found that diet-induced obesity decreased spermatozoid motility, testis and epididymis relative coefficients, and plasma testosterone and luteinizing hormone levels. An increased number and volume of lipid droplets in Leydig cells were observed in the DIO group compared to the control group. Significantly, higher serum leptin levels were found in the DIO and DIO-R groups. The DIO and DIO-R groups showed significant downregulation of the GnRH, Kiss1, GPR54, and Ob-R genes. We also found decreased levels of GnRH, kisspeptin, GPR54, and Ob-R protein in the DIO and DIO-R groups.

CONCLUSIONS

These lines of evidence suggest that downregulation of Ob-R and kisspeptin/GPR54 in the murine hypothalamus may contribute to male hypogonadism caused by high-fat diet-induced obesity.

Insulin Resistance, Hyperinsulinemia, and LH: Relative Roles in Peripubertal Obesity-Associated Hyperandrogenemia

CONTEXT

Peripubertal obesity is associated with variable hyperandrogenemia, but precise mechanisms remain unclear.

OBJECTIVE

To assess insulin resistance, hyperinsulinemia, and LH roles in peripubertal obesity-associated hyperandrogenemia.

DESIGN

Cross-sectional analysis.

SETTING

Academic clinical research unit.

PARTICIPANTS

Eleven obese (body mass index for age ≥95%) peripubertal girls.

INTERVENTION

Blood samples were taken during a mixed-meal tolerance test (1900 to 2100), overnight (2100 to 0700), while fasting (0700 to 0900), and during an 80 mU/m2/min hyperinsulinemic-euglycemic clamp (0900 to 1100).

MAIN OUTCOME MEASURES

The dependent variable was morning free testosterone level; independent variables were insulin sensitivity index (ISI), estimated 24-hour insulin, and estimated 24-hour LH levels.

RESULTS

All participants demonstrated insulin resistance and hyperinsulinemia. ISI, but not estimated 24-hour insulin level, correlated positively with morning free testosterone level when correcting for estimated 24-hour LH level and Tanner stage (rs = 0.68, P = 0.046). The correlation between estimated 24-hour LH and free testosterone levels approached significance after adjusting for estimated 24-hour insulin level and Tanner stage (rs = 0.63, P = 0.067). Estimated 24-hour insulin level did not correlate with free testosterone level after adjusting for estimated 24-hour LH level and Tanner stage (rs = 0.47, P = 0.20).

CONCLUSION

In insulin-resistant obese girls with hyperinsulinemia, free testosterone levels correlated positively with insulin sensitivity and, likely, circulating LH concentrations but not with circulating insulin levels. In the setting of relatively uniform hyperinsulinemia, variable steroidogenic-cell insulin sensitivity may correlate with metabolic insulin sensitivity and contribute to variable free testosterone concentrations.

Progesterone-Mediated Inhibition of the GnRH Pulse Generator: Differential Sensitivity as a Function of Sleep Status

CONTEXT

During normal, early puberty, luteinizing hormone (LH) pulse frequency is low while awake but increases during sleep. Mechanisms underlying such changes are unclear, but a small study in early pubertal girls suggested that differential wake-sleep sensitivity to progesterone negative feedback plays a role.

OBJECTIVE

To test the hypothesis that progesterone acutely reduces waking LH pulse frequency more than sleep-associated pulse frequency in late pubertal girls.

DESIGN

Randomized, placebo-controlled, double-blinded crossover study.

SETTING

Academic clinical research unit.

PARTICIPANTS

Eleven normal, postmenarcheal girls, ages 12 to 15 years.

INTERVENTION

Subjects completed two 18-hour admissions in separate menstrual cycles (cycle days 6 to 11). Frequent blood sampling for LH assessment was performed at 1800 to 1200 hours; sleep was encouraged at 2300 to 0700 hours. Either oral micronized progesterone (0.8 mg/kg/dose) or placebo was given at 0700, 1500, 2300, and 0700 hours, before and during the first admission. A second admission, performed at least 2 months later, was identical to the first except that placebo was exchanged for progesterone or vice versa (treatment crossover).

MAIN OUTCOME MEASURES

LH pulse frequency during waking and sleeping hours.

RESULTS

Progesterone reduced waking LH pulse frequency by 26% (P = 0.019), with no change observed during sleep (P = 0.314). The interaction between treatment condition (progesterone vs placebo) and sleep status (wake vs sleep) was highly significant (P = 0.007).

CONCLUSIONS

In late pubertal girls, progesterone acutely reduced waking LH pulse frequency more than sleep-associated pulse frequency. Differential wake-sleep sensitivity to progesterone negative feedback may direct sleep-wake LH pulse frequency changes across puberty.

Influence of Sleep Stage on LH Pulse Initiation in the Normal Late Follicular Phase and in Polycystic Ovary Syndrome

OBJECTIVE

During the early follicular phase, sleep-related luteinizing hormone (LH) pulse initiation is positively associated with brief awakenings but negatively associated with rapid eye movement (REM) sleep. The relationship between sleep architecture and LH pulse initiation has not been assessed in other cycle stages or in women with polycystic ovary syndrome (PCOS).

DESIGN AND METHODS

We performed concomitant frequent blood sampling (LH pulse analysis) and polysomnography on 8 normal women (cycle day 7-11) and 7 women with PCOS (at least cycle day 7).

RESULTS

In the normal women, the 5 min preceding LH pulses contained more wake epochs and fewer REM epochs than the 5 min preceding randomly determined time points (wake: 22.3 vs. 9.1%, p = 0.0111; REM: 4.4 vs. 18.8%, p = 0.0162). However, LH pulse initiation was not related to wake or REM epochs in PCOS; instead, the 5 min preceding LH pulses contained more slow-wave sleep (SWS) than the 5 min before random time points (20.9 vs. 6.7%, p = 0.0089). Compared to the normal subjects, the women with PCOS exhibited a higher REM-associated LH pulse frequency (p = 0.0443) and a lower proportion of wake epochs 0-5 min before LH pulses (p = 0.0205).

CONCLUSIONS

Sleep-related inhibition of LH pulse generation during the later follicular phase is normally weakened by brief awakenings and strengthened by REM sleep. In women with PCOS, LH pulse initiation is not appropriately discouraged by REM sleep and may be encouraged by SWS; these abnormalities may contribute to a high sleep-related LH pulse frequency in PCOS.

Progesterone Suppression of Luteinizing Hormone Pulse Frequency in Adolescent Girls With Hyperandrogenism: Effects of Metformin

Context

Polycystic ovary syndrome (PCOS) and adolescent hyperandrogenism (HA) are characterized by rapid luteinizing hormone (LH) pulse frequency. This partly reflects impaired gonadotropin-releasing hormone pulse generator (hypothalamic) sensitivity to progesterone (P4) negative feedback. We assessed whether metformin may improve P4 sensitivity in adolescent HA, for which it is prescribed widely.

Objective

To test the hypothesis that metformin improves hypothalamic P4 sensitivity in adolescent HA.

Design

Nonrandomized, interventional trial.

Setting

Academic clinical research unit.

Participants

Ten adolescent girls with HA.

Intervention

The girls underwent LH sampling every 10 minutes for 11 hours, at study baseline and after 7 days of oral P4 and estradiol (E2). Participants then took metformin (1 g twice daily) for 9.4 to 13.7 weeks, after which participants again underwent frequent LH sampling before and after 7 days of oral P4 and E2 (while continuing metformin). Total and free testosterone (T) and fasting insulin were assessed at each admission. At admissions 1 and 3, 2-hour oral glucose tolerance tests were performed.

Main Outcome Measure

Metformin-related change in hypothalamic P4 sensitivity index [percent change in LH pulse frequency (before vs after P4 and E2) divided by day 7 P4 level].

Results

Free T levels decreased by 29% with metformin (P = 0.0137). Measures of hyperinsulinemia and P4 sensitivity index did not significantly change with metformin use.

Conclusion

Short-term metformin use improved biochemical hyperandrogenemia, but did not improve hypothalamic sensitivity to P4 suppression, in adolescent girls.

Prepubertal Development of Gonadotropin-Releasing Hormone Neuron Activity Is Altered by Sex, Age, and Prenatal Androgen Exposure

Gonadotropin-releasing hormone (GnRH) neurons regulate reproduction though pulsatile hormone release. Disruption of GnRH release as measured via luteinizing hormone (LH) pulses occurs in polycystic ovary syndrome (PCOS), and in young hyperandrogenemic girls. In adult prenatally androgenized (PNA) mice, which exhibit many aspects of PCOS, increased LH is associated with increased GnRH neuron action potential firing. How GnRH neuron activity develops over the prepubertal period and whether this is altered by sex or prenatal androgen treatment are unknown. We hypothesized GnRH neurons are active before puberty and that this activity is sexually differentiated and altered by PNA. Dams were injected with dihydrotestosterone (DHT) on days 16 to 18 post copulation to generate PNA mice. Action potential firing of GFP-identified GnRH neurons in brain slices from 1-, 2-, 3-, and 4-week-old and adult mice was monitored. GnRH neurons were active at all ages tested. In control females, activity increased with age through 3 weeks, then decreased to adult levels. In contrast, activity did not change in PNA females and was reduced at 3 weeks. Activity was higher in control females than males from 2 to 3 weeks. PNA did not affect GnRH neuron firing rate in males at any age. Short-term action potential patterns were also affected by age and PNA treatment. GnRH neurons are thus typically more active during the prepubertal period than adulthood, and PNA reduces prepubertal activity in females. Prepubertal activity may play a role in establishing sexually differentiated neuronal networks upstream of GnRH neurons; androgen-induced changes during this time may contribute to the adult PNA, and possibly PCOS, phenotype.

Independent relationship between body mass index and LH peak value of GnRH stimulation test in ICPP girls: A cross-sectional study

The effect of obesity on idiopathic central precocious puberty (ICPP) girls is still under discussion. The relationship between body mass index (BMI) and sexual hormone levels of gonadotropin-releasing hormone (GnRH) stimulation test in ICPP girls is controversial and the underlying mechanism is unclear. This study aims to further explore the independent effect of excess adiposity on peak luteinizing hormone (LH) level of stimulation test in ICPP girls and the role of other related factors. A retrospective cross-sectional study was performed on 618 girls diagnosed as having ICPP, including 355 cases of normal weight, 99 cases of overweight and 164 cases of obese. The results showed that obese group had more progressed Tanner stage and no significant difference (P=0.28) in LH peak was found as basal LH value was used as a covariate. The obese group had higher total testosterone (TT), adrenocorticotrophic hormone (ACTH), 17-α hydroxyprogesterone (17-αOHP) and androstendione (AN), with significantly increased fasting insulin (FIN) and homeostasis model of assessment for insulin resistance index (HOMA-IR). Stratified analysis showed inconsistency of the relationship between BMI-standard deviation score (BMI-SDS) and LH peak in different Tanner stages (P for interaction=0.017). Further smoothing plot showed linear and non-linear relationship between BMI-SDS and LH peak in three Tanner stages. Then linear regression model was used to analyze the relationship between BMI-SDS and LH peak in different Tanner stages, with and without different confounding factors being adjusted. In B2 stage, BMI-SDS was negatively associated with LH peak. In B3 stage, when BMI-SDS <1.5, as BMI-SDS increased, the level of LH peak decreased (model I: β=-1.8, 95% CI=-4.7 to 1.1, P=0.214). When BMI-SDS ≥1.5, BMI-SDS was significantly positively associated with LH peak (model I: β=4.5, 95% CI=1.7 to 7.4, P=0.002). In B4 stage, when BMI-SDS <1.5, BMI-SDS was negatively associated with LH peak (model I: β=-11.6, 95% CI=-22.7 to-0.5, P=0.049). When BMI-SDS ≥1.5, BMI-SDS was positively associated with LH peak (model I: β=-4.2, 95% CI=-3.3 to 11.7, P=0.28). It is concluded that there is an independent correlation between BMI-SDS and LH peak of stimulation test in ICPP girls, their relationships are different in different Tanner stages, and the effect of BMI-SDS can be affected by adrenal androgens, estradiol and glucose metabolism parameters.

Increased Adrenal Androgens in Overweight Peripubertal Girls

CONTEXT

Peripubertal hyperandrogenemia-a precursor to polycystic ovary syndrome-is prominent in girls with obesity.

OBJECTIVE

We examined sources of overnight testosterone (T) and progesterone (P4) and potential sources of obesity-associated hyperandrogenemia during puberty.

DESIGN

Cross-sectional.

SETTING

Research unit.

PARTICIPANTS/INTERVENTIONS

Fifty girls ages 7 to 18 years-both normal weight (NW) and overweight (OW)-underwent dexamethasone (DEX) suppression (1 mg orally; 10 pm) and cosyntropin stimulation testing (0.25 mg intravenously; 8 am the following day), with blood sampled before and 30 and 60 minutes after cosyntropin. Thirty-nine subjects receiving DEX had frequent blood sampling overnight (every 10 minutes from 10 pm to 7 am) and were compared with 70 historical controls who did not receive DEX.

OUTCOMES

Random coefficient regression modeling assessed changes in hormone concentrations after DEX and cosyntropin.

RESULTS

NW early pubertal controls exhibited early morning increases in free T and P4 levels; NW and OW late pubertal controls exhibited early morning increases in P4. Such changes were not observed in subjects receiving DEX. Post-DEX morning free T levels were fourfold higher in OW vs NW late pubertal girls. Postcosyntropin changes in free T and androstenedione were both 2.3-fold higher in OW vs NW late pubertal girls.

CONCLUSIONS

These data suggest that (1) overnight increases in free T and P4 concentrations in NW early pubertal girls and P4 concentrations in late pubertal girls are of adrenal origin and (2) OW late pubertal girls demonstrate elevated nonadrenal free T levels after DEX and exaggerated adrenal androgen (free T and androstenedione) responses to cosyntropin.

The impact of obesity on hyperandrogenemia in Korean girls

PURPOSE

As metabolic complication and polycystic ovarian syndrome due to childhood obesity is rising, the role of hyperandrogenemia (HA) and hyperinsulinism is receiving attention. The aims of this study were to investigate the presence of obvious HA according to pubertal status and to find potential etiologic determinants of HA in Korean obese (OB) girls.

METHODS

We analyzed 91 girls aged 6-17 years (prepuberty, n=54; puberty, n=37). Each girl was classified as being either normal weight (NW) or OB. Anthropometric measurements were obtained and blood test was performed early in the morning after at least 8 hours of fasting to measure glucose, insulin, total testosterone, sex hormone-binding globulin, dehydroepiandrosterone sulfate (DHEAS), luteinizing hormone (LH), follicular-stimulating hormone, estradiol, and progesterone.

RESULTS

The plasma levels of free testosterone (FT) and DHEAS were markedly higher in OB girls compared to NW girls in puberty (FT, P=0.009; DHEAS, P=0.046) but not in prepuberty (FT, P=0.183; DHEAS, P=0.052). Hyperinsulinemia and high homeostasis model assessment of insulin resistance (HOMA-IR) values were found regardless of pubertal status in OB girls. The significant related factor to HA in puberty was the body mass index Z-score (P=0.003). But HOMA-IR, LH, and progesterone levels were not relevant to HA in pubertal girls.

CONCLUSION

OB prepubertal girls did not show HA in the present study but they should be regularly monitored because they already had hyperinsulinemia. OB pubertal girls had significant HA and hyperinsulinemia, and obesity per se was the most important factor for HA.

Luteinizing Hormone Secretion during Gonadotropin-Releasing Hormone Stimulation Tests in Obese Girls with Central Precocious Puberty

OBJECTIVE

Girls with precocious puberty have high luteinizing hormone (LH) levels and advanced bone age. Obese children enter puberty at earlier ages than do non-obese children. We analyzed the effects of obesity on LH secretion during gonadotropin-releasing hormone (GnRH) tests in girls with precocious puberty.

METHODS

A total of 981 subjects with idiopathic precocious puberty who had undergone a GnRH stimulation testing between 2008 and 2014 were included in the study. Subjects were divided into three groups based on body mass index (BMI). Auxological data and gonadotropin levels after the GnRH stimulation test were compared.

RESULTS

In Tanner stage 2 girls, peak stimulated LH levels on GnRH test were 11.9±7.5, 10.4±6.4, and 9.1±6.1 IU/L among normal-weight, overweight, and obese subjects, respectively (p=0.035 for all comparisons). In Tanner stage 3 girls, peak stimulated LH levels were 14.9±10.9, 12.8±7.9, and 9.6±6.0 IU/L, respectively (p=0.022 for all comparisons). However, in Tanner stage 4 girls, peak stimulated LH levels were not significantly different among normal, overweight, and obese children. On multivariate analysis, BMI standard deviation score was significantly and negatively associated with peak LH (β=-1.178, p=0.001).

CONCLUSION

In girls with central precocious puberty, increased BMI was associated with slightly lower peak stimulated LH levels at early pubertal stages (Tanner stages 2 and 3). This association was not valid in Tanner stage 4 girls.

Progesterone has rapid positive feedback actions on LH release but fails to reduce LH pulse frequency within 12 h in estradiol-pretreated women

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

Genetic, hormonal and metabolic aspects of PCOS: an update

Polycystic ovary syndrome (PCOS) is a complex endocrine disorder affecting 5-10 % of women of reproductive age. It generally manifests with oligo/anovulatory cycles, hirsutism and polycystic ovaries, together with a considerable prevalence of insulin resistance. Although the aetiology of the syndrome is not completely understood yet, PCOS is considered a multifactorial disorder with various genetic, endocrine and environmental abnormalities. Moreover, PCOS patients have a higher risk of metabolic and cardiovascular diseases and their related morbidity, if compared to the general population.

Polycystic Ovary Syndrome in Adolescents

Polycystic ovary syndrome (PCOS) is a familial heterogeneous disorder affecting 6% to 10% of reproductive-age women. The use of criteria developed for adult women is problematic for the adolescent girl because the clinical features associated with PCOS are normal pubertal events. The recent consensus statement on PCOS in adolescents stated that hyperandrogenism and oligomenorrhea need to persist for at least 2 years to consider the diagnosis of PCOS. Although insulin resistance, hyperinsulinism, and obesity are often associated with PCOS, these features are not considered valid diagnostic criteria. Recent genomewide association studies implicate genetic loci involved in the hypothalamic-pituitary-ovarian axis.

Increases in Sex Hormones during Anti-Tumor Necrosis Factor α Therapy in Adolescents with Crohn's Disease

OBJECTIVE

To evaluate children with Crohn's disease for inverse relationships between systemic inflammatory cytokines and sex hormone regulation in the context of anti-tumor necrosis factor α (TNF-α) therapy.

STUDY DESIGN

An observational study design was used to assess sex hormone and gonadotropin levels at the time of initiation of anti-TNF-α therapy and 10 weeks and 12 months later in 72 adolescents (Tanner stage 2-5) with Crohn's disease. Mixed-model linear regression was used to evaluate relationships between hormone levels, systemic inflammation, and dual-energy x-ray absorptiometry whole-body fat mass Z scores over the study interval.

RESULTS

Sex hormone Z scores increased significantly during the 10-week induction interval: testosterone Z scores in male patients increased from a median of -0.36 to 0.40 (P < .05) and estradiol Z scores in females increased from -0.35 to -0.02 (P < .01). In mixed model regression, the pediatric Crohn's disease activity index score, cytokine levels, and measures of inflammation were significantly and negatively associated with sex hormone Z scores and with luteinizing hormone and follicle-stimulating hormone levels, adjusted for sex and Tanner stage. Sex hormone and gonadotropin levels were not associated with body mass index or fat mass Z-scores.

CONCLUSIONS

Crohn's disease is associated with delayed maturation, and initiation of anti-TNF-α therapy was associated with significant and rapid increases in sex hormone and gonadotropin levels, in association with improvements in disease activity and measures of inflammation. These data are consistent with preclinical studies of the effects of inflammation on sex hormone regulation.

Association of Obesity with Onset of Puberty and Sex Hormones in Chinese Girls: A 4-Year Longitudinal Study

Objective

To examine the influence of childhood obesity on the early onset of puberty and sex hormones in girls.

Methods

Healthy girls with different percentages of body fat at baseline (40 obese, 40 normal, and 40 lean) were recruited from three elementary schools in Shenyang, China. These girls (mean age 8.5 years) were also matched by height, school grade, Tanner stage, and family economic status at baseline. Anthropometry, puberty characteristics, and sex hormone concentrations were measured at baseline and at each follow-up visit. The generalized estimating equation model and analysis of variance for repeated measures using a generalized linear model were used to determine the differences in puberty characteristics and sex hormones among three groups.

Results

Over 4 years, mean age of breast II onset was earlier among obese girls (8.8 years) than normal girls (9.2 years) and lean girls (9.3 years). The prevalence (%) of early-maturation in the obese, normal, and lean groups was 25.9%, 11.1%, and 7.4%, respectively. Obesity was associated with an increased risk for breast stage II (year 2: RR, 6.3; 95% CI, 1.9–21.1 and year 3: RR, 6.9; 95% CI, 0.8–60.1). None of the girls experienced menarche in the first year; however, by the fourth year 50.0% of obese girls had menarche onset, which was higher than normal weight (27.5%) and lean girls (8.1%). The mean estradiol level increased with age in the obese, normal, and lean groups. The mean estradiol concentration was higher in obese girls than in normal and lean girls throughout the 4-year period (P<0.05).

Conclusions

Childhood obesity contributes to early onset of puberty and elevated levels of estradiol in girls.

BMI percentile-for-age overestimates adiposity in early compared with late maturing pubertal children

OBJECTIVE

Early pubertal timing is consistently associated with increased BMI percentile-for-age in pubertal girls, while data in boys are more ambiguous. However, higher BMI percentile-for-age may be a result of the earlier puberty per se rather than vice versa. The aim was to evaluate markers of adiposity in relation to pubertal timing and reproductive hormone levels in healthy pubertal boys and girls.

STUDY DESIGN

Population-based cross-sectional study (The Copenhagen Puberty Study). Eight-hundred and two healthy Caucasian children and adolescents (486 girls) aged 8.5-16.5 years participated. BMI and bioelectric impedance analyses (BIA) were used to estimate adiposity. Clinical pubertal markers (Tanner stages and testicular volume) were evaluated. LH, FSH, estradiol, testosterone, SHBG and IGF1 levels were determined by immunoassays.

RESULTS

In all age groups, higher BMI (all 1 year age-groups, P ≤ 0.041) was found with early compared with late maturation, despite similar BIA-estimated body fat percentage (BIA-BF%). Neither BMI nor BIA-BF% differed for a given stage of maturation. BMI percentile-for-age and prevalence of overweight/obesity were higher in the early compared with late matured pubertal children (all P ≤ 0.038), despite similar BIA-BF%. Pubertal girls with BIA-BF >29% had significantly lower LH and FSH levels compared with normal-weight girls (P ≤ 0.041).

CONCLUSIONS

Early maturational timing was not associated with higher adiposity for a given stage of puberty. Using BMI percentile-for-age overestimated the degree of adiposity in early pubertal compared with late pubertal children.

Adolescent polycystic ovary syndrome due to functional ovarian hyperandrogenism persists into adulthood

BACKGROUND

Menstrual irregularity and above-average testosterone levels in adolescence may presage polycystic ovary syndrome (PCOS) in adulthood but persist in only a minority. Prolonged anovulatory cycles in normal adolescents are associated with increased testosterone levels. Thus, questions have been raised about the accuracy of PCOS diagnosed in adolescents.

OBJECTIVE

The purpose of this study was to follow-up hyperandrogenic adolescents with features of PCOS to test the hypothesis that adolescent functional ovarian hyperandrogenism (FOH) persists into adulthood.

STUDY SUBJECTS

A series of adults previously reported to have adolescent PCOS, with most documented to have FOH by GnRH agonist or dexamethasone androgen-suppression test criteria, were recalled.

METHODS

Recall occurred >3 years after the initial diagnosis and at the age of >18.0 years. Respondents underwent examination, baseline androgen evaluation, and an oral glucose tolerance test after discontinuing oral contraceptive therapy.

RESULTS

Of the adolescent hyperandrogenic patients, 68% (15 of 22) were traceable, and 60% of those traced returned for follow-up, including half (n = 8) of the original FOH group. The baseline characteristics of respondents and nonrespondents were not significantly different. Patients with FOH were reevaluated when their mean age was 23.0 years (range, 18.4-29.4 years), gynecologic age was 10.7 years (range, 5.5-18.4 years), and body mass index was 42.3 kg/m(2) (range, 28.3-52.1 kg/m(2); P = .02 vs adolescence). Serum free testosterone was 24 pg/mL (range, 10-38 pg/mL, normal, 3-9 pg/mL; not significant vs adolescence); all were oligomenorrheic. Whereas 3 of 8 had impaired glucose tolerance as adolescents, at follow-up 6 of 8 had developed abnormal glucose tolerance (2 with type 2 diabetes mellitus).

CONCLUSIONS

Adolescents with FOH, which underlies most PCOS, uniformly have persistent hyperandrogenism, and glucose tolerance tends to deteriorate. Testing ovarian androgenic function in hyperandrogenic adolescents may be of prognostic value.

Impact of maternal malnutrition during the periconceptional period on mammalian preimplantation embryo development

During episodes of undernutrition and overnutrition the mammalian preimplantation embryo undergoes molecular and metabolic adaptations to cope with nutrient deficits or excesses. Maternal adaptations also take place to keep a nutritional microenvironment favorable for oocyte development and embryo formation. This maternal-embryo communication takes place via several nutritional mediators. Although adaptive responses to malnutrition by both the mother and the embryo may ensure blastocyst formation, the resultant quality of the embryo can be compromised, leading to early pregnancy failure. Still, studies have shown that, although early embryonic mortality can be induced during malnutrition, the preimplantation embryo possesses an enormous plasticity that allows it to implant and achieve a full-term pregnancy under nutritional stress, even in extreme cases of malnutrition. This developmental strategy, however, may come with a price, as shown by the adverse developmental programming induced by even subtle nutritional challenges exerted exclusively during folliculogenesis and the preimplantation period, resulting in offspring with a higher risk of developing deleterious phenotypes in adulthood. Overall, current evidence indicates that malnutrition during the periconceptional period can induce cellular and molecular alterations in preimplantation embryos with repercussions for fertility and postnatal health.

The Diagnosis of Polycystic Ovary Syndrome during Adolescence

BACKGROUND/AIMS

The diagnostic criteria for polycystic ovary syndrome (PCOS) in adolescence are controversial, primarily because the diagnostic pathological features used in adult women may be normal pubertal physiological events. Hence, international pediatric and adolescent specialty societies have defined criteria that have sufficient evidence to be used for the diagnosis of PCOS in adolescents.

METHODS

The literature has been reviewed and evidence graded to address a series of questions regarding the diagnosis of PCOS during adolescence including the following: clinical and biochemical evidence of hyperandrogenism, criteria for oligo-anovulation and polycystic ovary morphology, diagnostic criteria to exclude other causes of hyperandrogenism and amenorrhea, role of insulin resistance, and intervention.

RESULTS AND CONCLUSION

Features of PCOS overlap normal pubertal development. Hence, caution should be taken before diagnosing PCOS without longitudinal evaluation. However, treatment may be indicated even in the absence of a definitive diagnosis. While obesity, insulin resistance, and hyperinsulinemia are common findings in adolescents with hyperandrogenism, these features should not be used to diagnose PCOS among adolescent girls. © 2015 S. Karger AG, Basel.

Accumulated deep sleep is a powerful predictor of LH pulse onset in pubertal children

CONTEXT

During puberty, reactivation of the reproductive axis occurs during sleep, with LH pulses specifically tied to deep sleep. This association suggests that deep sleep may stimulate LH secretion, but there have been no interventional studies to determine the characteristics of deep sleep required for LH pulse initiation.

OBJECTIVE

The objective of this study was to determine the effect of deep sleep fragmentation on LH secretion in pubertal children.

DESIGN AND SETTING

Studies were performed in a clinical research center.

SUBJECTS

Fourteen healthy pubertal children (11.3-14.1 y) participated in the study.

INTERVENTIONS

Subjects were randomized to two overnight studies with polysomnography and frequent blood sampling, with or without deep sleep disruption via auditory stimuli.

RESULTS

An average of 68.1 ±10.7 (± SE) auditory stimuli were delivered to interrupt deep sleep during the disruption night, limiting deep sleep to only brief episodes (average length disrupted 1.3 ± 0.2 min vs normal 7.1 ± 0.8 min, P < .001), and increasing the number of transitions between non-rapid eye movement (NREM), REM, and wake (disrupted 274.5 ± 33.4 vs normal 131.2 ± 8.1, P = .001). There were no differences in mean LH (normal: 3.2 ± 0.4 vs disrupted: 3.2 ± 0.5 IU/L), LH pulse frequency (0.6 ± 0.06 vs 0.6 ± 0.07 pulses/h), or LH pulse amplitude (2.8 ± 0.4 vs 2.8 ± 0.4 IU/L) between the two nights. Poisson process modeling demonstrated that the accumulation of deep sleep in the 20 minutes before an LH pulse, whether consolidated or fragmented, was a significant predictor of LH pulse onset (P < .001).

CONCLUSION

In pubertal children, nocturnal LH augmentation and pulse patterning are resistant to deep sleep fragmentation. These data suggest that, even when fragmented, deep sleep is strongly related to activation of the GnRH pulse generator.

Impact of BMI on gonadorelin-stimulated LH peak in premenarcheal girls with idiopathic central precocious puberty

OBJECTIVE

To clarify the impact of body mass index (BMI) on luteinizing hormone (LH) secretion in response to gonadorelin (GnRH) stimulation testing in girls diagnosed with idiopathic central precocious puberty (ICPP).

METHODS

Retrospective single-center cohort study was carried out in 865 confirmed ICPP girls who underwent GnRH stimulation tests. Pubertal development according to Tanner, sex hormone parameters, and LH secretion in response to GnRH-stimulation was compared.

RESULTS

Around 609 girls were of normal weight (70.4%), while 168 children (19.4%) were overweight, and 88 (10.2%) were obese. Peak LH levels after GnRH were much higher in the normal-weight group, with a median of 9.1 mIU ml(-1) (interquartile 5.2-13.1), compared with the median peak LH in the overweight and obese groups (8.5 mIU ml(-1), interquartile 5.3-11.6, and 6.2 mIU ml(-1), interquartile 5.3-11.0, respectively P < 0.001 for all comparisons). Peak LH/FSH ratio was also lower in the obese group (median 0.6, interquartile 0.68-0.90) compared with the normal-weight (median 0.8, interquartile 0.61-1.11) and overweight (median 0.8, interquartile 0.64-0.92) groups.

CONCLUSIONS

Higher BMI is associated with lower LH response to GnRH-stimulation testing in girls with ICPP. It is recommended that BMI should be considered when interpreting GnRH-stimulation tests.

Hormone changes in peripubertal girls

CONTEXT

Studies of hormone changes in the peripubertal period note increases in adrenal hormones prior to increases in sex steroids. It is unclear how these processes are related to each other, except through this temporal relationship.

OBJECTIVE

Examine relationships in adrenal and sex hormones in 252 peripubertal girls.

SETTING AND DESIGN

Longitudinal observation study. School districts, at the Cincinnati site of the Breast Cancer and the Environment Research Centers, between 2004-2010. Participants were recruited between ages 6 and 7 years of age and were seen every 6 months. Main outcome measures included height, weight, maturation status, and fasting blood specimen. Serum was analyzed for selected hormones every six months, beginning 30 months prior to, and extending to 6 months after, breast development. Androstenedione, estradiol, estrone, and T were measured by high-performance liquid chromatography (HPLC) with tandem mass spectrometry. Dehydroepiandrosterone-sulfate (DHEA-S) and SHBG also were measured.

RESULTS

DHEA-S concentrations increased 24 months before breast development; androstenedione and estrone between 12 to 18 months before breast development; whereas estradiol and T increased, and SHBG fell between 6 and 12 months before breast development. Girls with greater body mass index had lower estradiol concentrations at onset of breast development as well as 6 months after pubertal onset.

CONCLUSIONS

Serum estrone and DHEA-S increased prior to estradiol concentrations, and the increase in estradiol occurred prior to breast development. Heavier peripubertal girls have lower estradiol levels at puberty, suggesting peripheral conversion of adrenal androgens to estrone.

Sexual dimorphisms in the associations of BMI and body fat with indices of pubertal development in girls and boys

CONTEXT

The effect of obesity and concomitant insulin resistance on pubertal development is incompletely elucidated.

OBJECTIVE

To determine how measures of adiposity and insulin resistance are associated with pubertal maturation in boys and girls.

SETTING AND DESIGN

Breast and pubic hair Tanner stage and testicular volume by orchidometry were determined by physical examination in 1066 children. Ovarian volume was estimated by trans-abdominal ultrasound. Fat mass, skeletal age, and fasting serum for insulin and glucose, total T, estradiol, estrone, dehydroepiandrosterone-sulfate, and androstenedione were measured at the National Institutes of Health Clinical Research Center. Convenience sample; 52% obese, 59% female.

RESULTS

Logistic regression identified a significant interaction between sex and obesity for prediction of pubertal development (P ≤ .01). There was a negative association between boys' testicular volume and body mass index (BMI)/fat mass but a positive association between girls' breast stage and BMI/fat mass. Ovarian volume in girls was positively associated with insulin resistance but not with BMI/fat mass. There was a positive association between obesity and measures of estrogen exposure (breast development and skeletal age) in both sexes. Positive correlations were seen for girls between BMI and pubic hair development and between insulin resistance and T production, whereas adiposity was negatively associated with pubic hair in boys.

CONCLUSIONS

Significant sexual dimorphisms in the manifestations of pubertal development are seen in obese girls and boys. Two known effects of obesity, increased peripheral conversion of low-potency androgens to estrogens by adipose tissue-aromatase and increased insulin resistance, may be in large part responsible for these differences.

Blunted day-night changes in luteinizing hormone pulse frequency in girls with obesity: the potential role of hyperandrogenemia

CONTEXT

Puberty is marked by sleep-associated changes in LH pulse frequency and amplitude. Early pubertal girls with obesity exhibit blunted day-to-night changes in LH secretion; whether this occurs in late pubertal obese girls is unknown.

OBJECTIVE

The objective of the study was to test two hypotheses: 1) blunted day-to-night changes in LH secretion occur in both early and late pubertal obese girls, and 2) such alterations are specifically associated with hyperandrogenemia.

DESIGN

This was a cross-sectional analysis.

SETTING

The study was conducted at a clinical research center.

PATIENTS OR OTHER PARTICIPANTS

Twenty-seven early pubertal, premenarcheal girls (12 of whom were obese) and 63 late pubertal (postmenarcheal) girls (27 of whom were obese) participated in the study.

INTERVENTION

Blood samples were taken every 10 minutes from 7:00 pm to 7:00 am.

MAIN OUTCOME MEASURE

Change in LH pulse frequency [LH interpulse interval (IPI)] from daytime hours (7:00 pm-11:00 pm, while awake) to nighttime hours (11:00 pm to 7:00 am, while generally asleep).

RESULTS

Both nonobese and obese postmenarcheal girls demonstrated significant day-to-night decreases in LH pulse frequency (IPI increases of 33% and 16%, respectively), but day-to-night changes were blunted in obese girls (P = .004, obese vs nonobese). Day-to-night LH pulse frequency decreased significantly in postmenarcheal obese subjects with normal T concentrations (26% IPI increase) but not in those with hyperandrogenemia. Similar differences were evident for LH pulse amplitude. Nonobese and obese early pubertal girls exhibited nonsignificant differences in day-night LH pulse frequency (day to night IPI increase of 26% vs decrease of 1%, respectively).

CONCLUSIONS

Day-to-night changes in LH pulse secretion are blunted in postmenarcheal obese adolescent girls. This phenomenon may in part reflect hyperandrogenemia.