Androgen Stimulates Growth of Mouse Preantral Follicles In Vitro: Interaction With Follicle-Stimulating Hormone and With Growth Factors of the TGFβ Superfamily

LncRNA SNHG5 adversely governs follicular growth in PCOS via miR-92a-3p/CDKN1C axis

Small nucleolar RNA host genes (SNHGs) have been implicated in various biological processes, yet their involvement in polycystic ovary syndrome (PCOS) remains elusive. Specifically, SNHG5, a long non-coding RNA implicated in several human cancers, shows elevated expression in granulosa cells (GCs) of PCOS women and induces PCOS-like features when overexpressed in mice. In vitro, SNHG5 inhibits GC proliferation and induces apoptosis and cell-cycle arrest at G0/G1 phase, with RNA-seq indicating its impact on DNA replication and repair pathways. Mechanistically, SNHG5 acts as a competing endogenous RNA by binding to miR-92a-3p, leading to increased expression of target gene CDKN1C, which further suppresses GC proliferation and promotes apoptosis. These findings elucidate the crucial role of SNHG5 in the pathogenesis of PCOS and suggest a potential therapeutic target for this condition. Additional investigations such as large-scale clinical studies and functional assays are warranted to validate and expand upon these findings.

Subtle perturbations of ovarian steroidogenesis in patients classified as Poseidon Group 3. Which consequences for therapeutic strategy?

The optimal strategy for stimulation of young women with a low ovarian reserve is still a challenging issue because the physio-pathogeny of this disorder is often unknown. As androgen production by the ovary plays a crucial role in folliculogenesis, it was tempting to speculate that subtle perturbations in ovarian steroidogenesis might participate to the low responsiveness to gonadotrophins. Indeed, in vitro analysis of human luteinized granulosa cells has recently provided evidence for some enzymatic deficits in steroidogenesis and altered response to gonadotrophins. Therefore, improving androgen environment of women classified in Poseidon Group 3 should be considered. In this clinical situation, the potential benefit of androgen supplementation or stimulation of theca cells by LH-activity products are respectively discussed.

Paxillin knockout in mouse granulosa cells increases fecundity†

Paxillin is an intracellular adaptor protein involved in focal adhesions, cell response to stress, steroid signaling, and apoptosis in reproductive tissues. To investigate the role of paxillin in granulosa cells, we created a granulosa-specific paxillin knockout mouse model using Cre recombinase driven by the Anti-Müllerian hormone receptor 2 gene promoter. Female granulosa-specific paxillin knockout mice demonstrated increased fertility in later reproductive age, resulting in higher number of offspring when bred continuously up to 26 weeks of age. This was not due to increased numbers of estrous cycles, ovulated oocytes per cycle, or pups per litter, but this was due to shorter time to pregnancy and increased number of litters in the granulosa-specific paxillin knockout mice. The number of ovarian follicles was not significantly affected by the knockout at 30 weeks of age. Granulosa-specific paxillin knockout mice had slightly altered estrous cycles but no difference in circulating reproductive hormone levels. Knockout of paxillin using clustered regularly interspaced short palindromic repeat-associated protein 9 (CRISPR-Cas9) in human granulosa-derived immortalized KGN cells did not affect cell proliferation or migration. However, in cultured primary mouse granulosa cells, paxillin knockout reduced cell death under basal culture conditions. We conclude that paxillin knockout in granulosa cells increases female fecundity in older reproductive age mice, possibly by reducing granulosa cell death. This study implicates paxillin and its signaling network as potential granulosa cell targets in the management of age-related subfertility.

Optimisation of hormonal treatment to improve follicular development in one-day-old mice ovaries cultured under in vitro condition

CONTEXT

Base medium containing knock-out serum replacement (KSR) has been found to support formation and maintenance of follicles in one-day-old mice ovaries, but has not been shown to properly support activation and growth of primordial follicles.

AIMS

The present study was conducted to tailor the hormonal content of base medium containing KSR to enhance development of primordial follicles in neonatal ovaries.

METHODS

One-day-old mice ovaries were initially cultured with base medium for four days, and then, different hormonal treatments were added to the culture media and the culture was proceeded for four additional days until day eight. Ovaries were collected for histological and molecular assessments on days four and eight.

KEY RESULTS

In experiment I, the main and interactive effects of FSH and testosterone were investigated and FSH promoted activation of primordial follicles and development of primary and preantral follicles, and upregulated genes of phosphoinositide 3-kinase (Pi3k ), KIT ligand (Kitl ), growth differentiation factor 9 (Gdf9 ) and follicle stimulating hormone receptor (Fshr ) (P Bmp15 ), Connexin-43 (Cx43 ) and luteinising hormone and choriogonadotropin receptor (Lhcgr ) (P P Lhcgr (P P >0.05).

CONCLUSIONS

Supplementation of culture medium containing KSR with gonadotropins, particularly hMG, could improve follicular growth and expression of factors regulating follicular development.

IMPLICATIONS

This study was a step forward in formulating an optimal medium for development of follicles in cultured one-day-old mice ovaries.

Current Advances in Cellular Approaches for Pathophysiology and Treatment of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a prevalent gynecological and endocrine disorder that results in irregular menstruation, incomplete follicular development, disrupted ovulation, and reduced fertility rates among affected women of reproductive age. While these symptoms can be managed through appropriate medication and lifestyle interventions, both etiology and treatment options remain limited. Here we provide a comprehensive overview of the latest advancements in cellular approaches utilized for investigating the pathophysiology of PCOS through in vitro cell models, to avoid the confounding systemic effects such as in vitro fertilization (IVF) therapy. The primary objective is to enhance the understanding of abnormalities in PCOS-associated folliculogenesis, particularly focusing on the aberrant roles of granulosa cells and other relevant cell types. Furthermore, this article encompasses analyses of the mechanisms and signaling pathways, microRNA expression and target genes altered in PCOS, and explores the pharmacological approaches considered as potential treatments. By summarizing the aforementioned key findings, this article not only allows us to appreciate the value of using in vitro cell models, but also provides guidance for selecting suitable research models to facilitate the identification of potential treatments and understand the pathophysiology of PCOS at the cellular level.

Androgen signalling in the ovaries and endometrium

Currently, our understanding of hormonal regulation within the female reproductive system is largely based on our knowledge of estrogen and progesterone signalling. However, while the important functions of androgens in male physiology are well known, it is also recognized that androgens play critical roles in the female reproductive system. Further, androgen signalling is altered in a variety of gynaecological conditions, including endometriosis and polycystic ovary syndrome, indicative of regulatory roles in endometrial and ovarian function. Co-regulatory mechanisms exist between different androgens, estrogens, and progesterone, resulting in a complex network of steroid hormone interactions. Evidence from animal knockout studies, in vitro experiments, and human data indicate that androgen receptor expression is cell-specific and menstrual cycle stage-dependent, with important regulatory roles in the menstrual cycle, endometrial biology, and follicular development in the ovaries. This review will discuss the expression and co-regulatory interactions of androgen receptors, highlighting the complexity of the androgen signalling pathway in the endometrium and ovaries, and the synthesis of androgens from additional alternative pathways previously disregarded as male-specific. Moreover, it will illustrate the challenges faced when studying androgens in female biology, and the need for a more in-depth, integrative view of androgen metabolism and signalling in the female reproductive system.

Higher live birth rate following transdermal testosterone pretreatment in poor responders: a systematic review and meta-analysis

A systematic review and meta-analysis was performed aiming to identify good-quality randomized controlled trials (RCT) evaluating testosterone pretreatment in poor responders. Eight RCTs were analysed, evaluating 797 women. Transdermal testosterone gel was used in all studies, with a dose ranging from 10 to 12.5 mg/day for 10-56 days. The main outcome measure was achievement of pregnancy, expressed as clinical pregnancy or live birth. Testosterone pretreatment was associated with a significantly higher live birth (risk ratio [RR] 2.07, 95% confidence interval [CI] 1.09-3.92) and clinical pregnancy rate (RR 2.25, 95% CI 1.54-3.30), as well as a significant increase in the number of cumulus-oocyte complexes retrieved. Significantly fewer days to complete ovarian stimulation, a lower total dose of gonadotrophins, a lower cancellation rate due to poor ovarian response and a thicker endometrium on the day of triggering of final oocyte maturation were observed. No significant differences were observed in oestradiol concentration, the numbers of follicles ≥17 mm, metaphase II oocytes, two-pronuclear oocytes and embryos transferred, and the proportion of patients with embryo transfer. The current study suggests that the probability of pregnancy is increased in poor responders pretreated with transdermal testosterone who are undergoing ovarian stimulation for IVF.

Androgen receptor signaling regulates follicular growth and steroidogenesis in interaction with gonadotropins in the ovary during mini-puberty in mice

In females, androgens contribute to ovarian diseases such as polycystic ovarian syndrome (PCOS), but their action is also crucial for ovarian physiology, i.e., follicular growth and estradiol (E2) synthesis during reproductive life, in interaction with the gonadotropins LH and FSH. However, it is unclear whether androgens already play a role in the ovary at mini-puberty, a phase of postnatal development with active follicular growth and high E2 levels. Therefore, we analyzed the potential actions of androgens on the ovary and their possible interaction with gonadotropins during this period in mice. We used molecular-based studies and pharmacological approaches in vivo and on cultured ovaries. We found that mini-pubertal ovaries produce significant amounts of testosterone and display androgen receptor (AR) expression in growing follicles, both under the control of LH. By blocking AR signaling either in vivo or in ovarian cultures, we found that this pathway may participate in the regulation of prepubertal E2 synthesis and follicular growth, possibly by regulating the expression of a number of key intra-ovarian regulators, including FSH receptor (Fshr), the aromatase enzyme converting androgens into estrogens (Cyp19a1) and the cell cycle inhibitor p27KIP1 (Cdkn1b). We further showed that AR may stimulate FSH-mediated regulation of Cyp19a1 through its action on Fshr mRNA abundance. Overall, this work supports the idea that AR signaling is already activated in mini-pubertal ovaries to regulate E2 synthesis and follicular growth, at the interplay with LH and FSH signaling. Its early action may, thus, contribute to the implementation of early ovarian function with possible impacts on reproductive function.

Age-related changes in Folliculogenesis and potential modifiers to improve fertility outcomes - A narrative review

Reproductive aging is characterized by a decline in oocyte quantity and quality, which is directly associated with a decline in reproductive potential, as well as poorer reproductive success and obstetrical outcomes. As women delay childbearing, understanding the mechanisms of ovarian aging and follicular depletion have become increasingly more relevant. Age-related meiotic errors in oocytes are well established. In addition, it is also important to understand how intraovarian regulators change with aging and how certain treatments can mitigate the impact of aging. Individual studies have demonstrated that reproductive pathways involving antimullerian hormone (AMH), vascular endothelial growth factor (VEGF), neurotropins, insulin-like growth factor 1 (IGF1), and mitochondrial function are pivotal for healthy oocyte and cumulus cell development and are altered with increasing age. We provide a comprehensive review of these individual studies and explain how these factors change in oocytes, cumulus cells, and follicular fluid. We also summarize how modifiers of folliculogenesis, such as vitamin D, coenzyme Q, and dehydroepiandrosterone (DHEA) may be used to potentially overcome age-related changes and enhance fertility outcomes of aged follicles, as evidenced by human and rodent studies.

Key signalling pathways underlying the aetiology of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine condition characterised by a range of reproductive, endocrine, metabolic and psychological abnormalities. Reports estimate that around 10% of women of reproductive age are affected by PCOS, representing a significant prevalence worldwide, which poses a high economic health burden. As the origin of PCOS remains largely unknown, there is neither a cure nor mechanism-based treatments leaving patient management suboptimal and focused solely on symptomatic treatment. However, if the underlying mechanisms underpinning the development of PCOS were uncovered then this would pave the way for the development of new interventions for PCOS. Recently, there have been significant advances in our understanding of the underlying pathways likely involved in PCOS pathogenesis. Key insights include the potential involvement of androgens, insulin, anti-Müllerian hormone and transforming growth factor beta in the development of PCOS. This review will summarise the significant scientific discoveries on these factors that have enhanced our knowledge of the mechanisms involved in the development of PCOS and discuss the impact these insights may have in shaping the future development of effective strategies for women with PCOS.

AOP key event relationship report: Linking decreased androgen receptor activation with decreased granulosa cell proliferation of gonadotropin-independent follicles

We recently proposed to formally recognize Key Event Relationships (KERs) as building blocks of Adverse Outcome Pathways (AOPs) that can be independently developed and peer-reviewed. Here, we follow this approach and provide an independent KER from AOP345, which describes androgen receptor (AR) antagonism leading to decreased female fertility. This KER connects AR antagonism to reduced granulosa cell proliferation of gonadotropin-independent follicles (KER2273). We have developed both the KER and the two adjacent Key Events (KEs). A systematic approach was used to ensure that all relevant supporting evidence for KER2273 was retrieved. Supporting evidence for the KER highlights the importance of AR action during the early stages of follicular development. Both biological plausibility and empirical evidence are presented, with the latter also assessed for quality. We believe that tackling isolated KERs instead of whole AOPs will accelerate the AOP development. Faster AOP development will lead to the development of simple test methods that will aid screening of chemicals, endocrine disruptor identification, risk assessment, and subsequent regulation.

Androgens and diminished ovarian reserve: the long road from basic science to clinical implementation. A comprehensive and systematic review with meta-analysis

OBJECTIVE

This study aimed to present a narrative review regarding androgen production, androgens' role in folliculogenesis, and the available therapeutic approaches for androgen supplementation, and to perform a systematic review and meta-analysis regarding the impact of androgens (dehydroepiandrosterone/testosterone) compared with placebo or no treatment on ovarian response and pregnancy outcomes in patients with diminished ovarian reserve and/or poor ovarian responders.

DATA SOURCES

An electronic search of MEDLINE, Embase, Cochrane Library, Cochrane Central Register of Controlled Trials, Scopus, ClinicalTrials.gov, the ISRCTN registry, and the World Health Organization International Clinical Trials Registry, was conducted for studies published until September 2021.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials that compared ovarian response and/or pregnancy outcomes between the different in vitro fertilization protocols using androgens (ie, dehydroepiandrosterone and testosterone) and conventional in vitro fertilization stimulation in patients with diminished ovarian reserve and/or poor ovarian responders were included.

METHODS

The quality of each study was evaluated with the revised Cochrane risk-of-bias tool for randomized trials (RoB 2). The meta-analysis used random-effects models. All results were interpreted on the basis of intention-to-treat analysis (defined as the inclusion of all randomized patients in the denominator). Risk ratios and 95% confidence intervals were used and combined for meta-analysis.

RESULTS

No significant differences were found regarding the number of oocytes retrieved (mean difference, 0.76; 95% confidence interval, -0.35 to 1.88), mature oocytes retrieved (mean difference, 0.25; 95% confidence interval, -0.27 to 0.76), clinical pregnancy rate (risk ratio, 1.17; 95% confidence interval, 0.87-1.57), live-birth rate (risk ratio, 0.97; 95% confidence interval, 0.47-2.01), or miscarriage rate (risk ratio, 0.80; 95% confidence interval, 0.29-2.22) when dehydroepiandrosterone priming was compared with placebo or no treatment. Testosterone pretreatment yielded a higher number of oocytes retrieved (mean difference, 0.94; 95% confidence interval, 0.46-1.42), a higher clinical pregnancy rate (risk ratio, 2.07; 95% confidence interval, 1.33-3.20), and higher live-birth rate (risk ratio, 2.09; 95% confidence interval, 1.11-3.95).

CONCLUSION

Although dehydroepiandrosterone did not present a clear effect on outcomes of assisted reproductive techniques, we found a potentially beneficial effect of testosterone priming on ovarian response and pregnancy outcomes. However, results should be interpreted with caution, taking into account the low to moderate quality of the available evidence.

Identification of key genes associated with polycystic ovary syndrome (PCOS) and ovarian cancer using an integrated bioinformatics analysis

BACKGROUND

Accumulating evidence suggests a strong association between polycystic ovary syndrome (PCOS) and ovarian cancer (OC), but the potential molecular mechanism remains unclear. In this study, we identified previously unrecognized genes that are significantly correlated with PCOS and OC via bioinformatics.

MATERIALS AND METHODS

Multiple bioinformatic analyses, such as differential expression analysis, univariate Cox analysis, functional and pathway enrichment analysis, protein-protein interaction (PPI) network construction, survival analysis, and immune infiltration analysis, were utilized. We further evaluated the effect of OGN on FSHR expression via immunofluorescence.

RESULTS

TCGA-OC, GSE140082 (for OC) and GSE34526 (for PCOS) datasets were downloaded. Twelve genes, including RNF144B, LPAR3, CRISPLD2, JCHAIN, OR7E14P, IL27RA, PTPRD, STAT1, NR4A1, OGN, GALNT6 and CXCL11, were identified as signature genes. Drug sensitivity analysis showed that OGN might represent a hub gene in the progression of PCOS and OC. Experimental analysis found that OGN could increase FSHR expression, indicating that OGN could regulate the hormonal response in PCOS and OC. Furthermore, correlation analysis indicated that OGN function might be closely related to m6A and ferroptosis.

CONCLUSIONS

Our study identified a 12-gene signature that might be involved in the prognostic significance of OC. Furthermore, the hub gene OGN represent a significant gene involved in OC and PCOS progression by regulating the hormonal response.

Regulatory role of dihydrotestosterone on BMP-6 receptors in granular cells of sheep antral follicles

Bone morphogenetic protein-6 (BMP-6) and dihydrotestosterone (DHT) affect steroid synthesis in follicles and regulate cell proliferation in the ovaries of female animals. However, little is known about granular cells (GCs) in sheep. We identified the key BMP-6 receptors, activin receptor-like kinase(ALK-6), and bone morphogenetic protein receptor type 2 (BMPRII) in sheep follicles using immunohistochemistry (IHC) and immunofluorescence (IF). Both ALK-6 and BMPRII were expressed in the GC layer, GC membranes, and cytoplasm. We evaluated ALK-6 and BMPRII expression at the follicular development stage using quantitative real-time PCR and western blotting to detect sheep GCs from large, medium, and small follicles (diameters of ≥5, 2-5, and ≤2 mm, respectively). The mRNA abundance and protein expression of ALK-6 and BMPRII were significantly higher in GCs from large follicles compared to those in GCs from small follicles (P < 0.05) and were the lowest in GCs from medium follicles. To assess whether DHT affects ALK-6 and BMPRII expression in sheep GCs, we cultured GCs from large follicles in vitro then incubated them with DHT (10^-11, 10^-9, 10^-7 M). We found that 10^-7-M DHT significantly inhibited ALK-6 and BMPRII mRNA and protein (P < 0.05). We further explored whether DHT regulates ALK-6 and BMPRII through the nuclear androgen receptor (AR) pathway and found that 10^-6-M flutamide, a non-selective androgen inhibitor, partially relieved the inhibitory effect of 10^-7-M DHT on ALK-6 and BMPRII expression. Thus, GCs in sheep antral follicles differentially expressed ALK-6 and BMPRII at various stages, indicating that BMP-6 plays different roles to some extent during the development of antral follicles, and that high concentrations of DHT can inhibit the expression of ALK-6 and BMPRII via the androgen receptor pathway in sheep GCs. The present study aimed to determine the expression of the main BMP-6-related main receptors, namely, ALK-6 and BMPRII, during the development of GCs in sheep antral follicles and a potential mechanism of DHT regulation in sheep GCs. Our findings lay a foundation for the further exploration of the effects of ovarian BMP-6 expression on follicular development.

Disruption of Epidermal Growth Factor Receptor but Not EGF Blocks Follicle Activation in Zebrafish Ovary

Folliculogenesis is controlled by intimate communications between oocytes and surrounding follicle cells. Epidermal growth factor (EGF/Egf) is an important paracrine/autocrine factor in vertebrate ovary, and it is well known for its stimulation of oocyte maturation. However, the role of EGF signaling through its receptor (EGFR/Egfr) in ovarian folliculogenesis is poorly understood, especially at early stages of follicle development. In this study, we created zebrafish mutants for Egf (egf−/−) and Egfr (egfra−/− and egfrb−/−) by CRISPR/Cas9 technique. Surprisingly, these mutants all survived well with little abnormality in growth and development. Spermatogenesis and folliculogenesis were both normal in egf−/− males and females. Their fecundity was comparable to that of the wildtype fish at 4 months post-fertilization (mpf); however, the fertilization rate of mutant eggs (egf−/−) decreased significantly at 7 mpf. Interestingly, disruption of egfra (egfra−/−) led to failed follicle activation with folliculogenesis being blocked at primary–secondary growth transition (PG-SG transition), leading to female infertility, whereas the mutant males remained fertile. The mutant ovary (egfra−/−) showed abnormal expression of a substantial number of genes involved in oxidative metabolism, gene transcription, cytomembrane transport, steroid hormone biosynthesis, and immune response. The stunted PG oocytes in egfra−/− ovary eventually underwent degeneration after 6 months followed by sex reversal to males with functional testes. No abnormal phenotypes were found in the mutant of truncated form of EGFR (egfrb). In summary, our data revealed critical roles for EGFR signaling in early folliculogenesis, especially at the PG-SG transition or follicle activation.

Androgens improve ovarian follicle function impaired by glucocorticoids through an androgen-IGF1-FSH synergistic effect

High concentrations of glucocorticoids caused by chronic stress are known to affect ovarian function and cause diminished ovarian reserve. Androgens are essential for early-stage ovarian follicle development, but the effects and mechanisms of androgens on follicle development under chronic stress remain unclear. In this study, we aim to investigate the effects of high concentrations of glucocorticoids on the function of in vitro cultured ovarian cells and mouse early-stage ovarian follicles and to validate the hypothesis that androgen-insulin-like growth factor 1 (IGF1)-follicle-stimulating hormone (FSH) synergistic signaling helps to ameliorate the damage caused by high concentrations of glucocorticoids. KGN cells (human granulosa cell line) and mouse primary cells were treated with different concentrations of glucocorticoids, and the cell proliferation, apoptosis, and sex hormone secretion were detected. The effects of glucocorticoid and androgens on IGF1 receptor (IGF1R) and FSH receptor (FSHR) expression in KGN cells were detected by Western blot. Steroidogenic synthase expressions under androgens and androgen-IGF1-FSH combination treatment were examined by qPCR after manipulation using low and high concentrations of glucocorticoids. The mechanism of androgen regulation of IGF1R and FSHR was explored by small interfering RNA (siRNA) and chromatin immunoprecipitation (ChIP)-qPCR. Damage of glucocorticoids and the treatment effects of androgens were further validated in mouse ovarian follicles cultured in vitro. The results demonstrated that prolonged treatment with high-dose glucocorticoids reduced cell viability of granulosa cells, inhibited their sex hormone secretion, and impaired their sensitivity to IGF1 and FSH signaling by affecting IGF1R and FSHR functions. Androgens at an appropriate dose range improved early-stage follicle development and their hormone secretion under high-dose glucocorticoid treatment, which was related to increased transcription of Igf1r and Fshr. This work showed that excessive glucocorticoids impaired ovarian function and validated that balanced concentrations of androgens synergized with IGF1 and FSH to improve the function of early-stage ovarian follicles under conditions of chronic stress.

Effects of Androgen Excess-Related Metabolic Disturbances on Granulosa Cell Function and Follicular Development

Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disease in women of reproductive age. Ovarian dysfunction including abnormal steroid hormone synthesis and follicular arrest play a vital role in PCOS pathogenesis. Hyperandrogenemia is one of the important characteristics of PCOS. However, the mechanism of regulation and interaction between hyperandrogenism and ovulation abnormalities are not clear. To investigate androgen-related metabolic state in granulosa cells of PCOS patients, we identified the transcriptome characteristics of PCOS granulosa cells by RNA-seq. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of differentially expressed genes (DEGs) revealed that genes enriched in lipid metabolism pathway, fatty acid biosynthetic process and ovarian steroidogenesis pathway were abnormally expressed in PCOS granulosa cells in comparison with that in control. There are close interactions among these three pathways as identified by analysis of the protein-protein interaction (PPI) network of DEGs. Furthermore, in vitro mouse follicle culture system was established to explore the effect of high androgen and its related metabolic dysfunction on follicular growth and ovulation. RT-qPCR results showed that follicles cultured with dehydroepiandrosterone (DHEA) exhibited decreased expression levels of cumulus expansion-related genes (Has2, Ptx3, Tnfaip6 and Adamts1) and oocyte maturation-related genes (Gdf9 and Bmp15), which may be caused by impaired steroid hormone synthesis and lipid metabolism, thus inhibited follicular development and ovulation. Furthermore, the inhibition effect of DHEA on follicle development and ovulation was ameliorated by flutamide, an androgen receptor (AR) antagonist, suggesting the involvement of AR signaling. In summary, our study offers new insights into understanding the role of androgen excess induced granulosa cell metabolic disorder in ovarian dysfunction of PCOS patients.

Anti-Müllerian Hormone in Female Reproduction

Anti-Müllerian hormone (AMH), also called Müllerian inhibiting substance, was shown to be synthesized by the ovary in the 1980s. This article reviews the main findings of the past 20 years on the regulation of the expression of AMH and its specific receptor AMHR2 by granulosa cells, the mechanism of action of AMH, the different roles it plays in the reproductive organs, its clinical utility, and its involvement in the principal pathological conditions affecting women. The findings in respect of regulation tell us that AMH and AMHR2 expression is mainly regulated by bone morphogenetic proteins, gonadotropins, and estrogens. It has now been established that AMH regulates the different steps of folliculogenesis and that it has neuroendocrine effects. On the other hand, the importance of serum AMH as a reliable marker of ovarian reserve and as a useful tool in the prediction of the polycystic ovary syndrome (PCOS) and primary ovarian failure has also been acknowledged. Last but not least, a large body of evidence points to the involvement of AMH in the pathogenesis of PCOS.

Systemic and Intrafollicular Androgen Concentrations in Cycling Mares

The evidence that androgens regulate the folliculogenesis supports the hypothesis that intrafollicular testosterone (T), androstenedione (A₄) and dehydroepiandrosterone (DHEA) could be modified along follicular growth. The objective of this study was to evaluate the changes and related relationships between systemic and intrafollicular T, A₄ and DHEA in post-deviation and impending ovulation follicles. Sixty ovaries were taken after the slaughter of 30 clinically healthy mares. In according to the sizes, the follicles were classified in 3 different categories, as small (20-30 mm), medium (31-40 mm) and large (≥ 41 mm), and the follicular fluid (FF) samplings were extracted from each single follicle. Intrafollicular concentrations of T, A_4, and DHEA were significantly higher than systemic ones. Intrafollicular and systemic T and A₄ concentrations were strongly and positively correlated, and DHEA negatively. A₄ was the predominant androgen in FF. T and A₄ were positively and DHEA negatively correlated with the follicular diameter. T and A₄ significantly increased in large and medium than small follicle sizes. DHEA was significantly higher in small than medium and large follicle size. The increase of intrafollicular androgens suggests the presence of androgenic environment based in the biotransformation of DHEA in A₄ and later in T in the follicles, and the progressive oestradiol-17β (E₂) production with the advance of follicular growth. The evidence of significant correlations between systemic and intrafollicular androgens considerably helps to understanding more deeply the role of these steroids in the physiology of follicular development in the mare, adding a new segment of scientific literature.

Early preantral follicles of the domestic cat express gonadotropin and sex steroid signalling potential

Key biomolecular processes which regulate primordial ovarian follicle dormancy and early folliculogenesis in mammalian ovaries are not fully understood. The domestic cat is a useful model to study ovarian folliculogenesis and is the most relevant for developing in vitro growth methods to be implemented in wild felid conservation breeding programs. Previously, RNA-sequencing of primordial, primary, and secondary follicle samples from domestic cat implicated ovarian steroidogenesis and steroid reception during follicle development. Here we aimed to identify which sex steroid biosynthesis and metabolism enzymes, gonadotropin receptors, and sex steroid receptors are present and may be potential regulators. Differential gene expression, functional annotation, and enrichment analyses were employed and protein localisation was studied too. Gene transcripts for PGR, PGRMC1, AR (steroid receptors), CYP11A1, CYP17A1, HSD17B1 and HSD17B17 (steroidogenic enzymes), and STS (steroid metabolising enzyme) were significantly differentially expressed (Q values of ≤0.05). Differential gene expression increased in all transcripts during follicle transitions apart from AR which decreased by the secondary stage. Immunohistochemistry localised FSHR and LHCGR to oocytes at each stage. PGRMC1 immunostaining was strongest in granulosa cells whereas AR was strongest in oocytes throughout each stage. Protein signals for steroidogenic enzymes were only detectable in secondary follicles. Products of these significantly differentially expressed genes may regulate domestic cat preantral folliculogenesis. In vitro growth could be optimised as all early follicles express gonadotropin and steroid receptors meaning hormone interaction and response may be possible. Protein expression analyses of early secondary follicles supported its potential for producing sex steroids.

Alteration of TGFB1, GDF9, and BMPR2 gene expression in preantral follicles of an estradiol valerate-induced polycystic ovary mouse model can lead to anovulation, polycystic morphology, obesity, and absence of hyperandrogenism

Objective

In humans, polycystic ovary syndrome (PCOS) is an androgen-dependent ovarian disorder. Aberrant gene expression in folliculogenesis can arrest the transition of preantral to antral follicles, leading to PCOS. We explored the possible role of altered gene expression in preantral follicles of estradiol valerate (EV) induced polycystic ovaries (PCO) in a mouse model.

Methods

Twenty female balb/c mice (8 weeks, 20.0±1.5 g) were grouped into control and PCO groups. PCO was induced by intramuscular EV injection. After 8 weeks, the animals were killed by cervical dislocation. Blood serum (for hormonal assessments using the enzyme-linked immunosorbent assay technique) was aspirated, and ovaries (the right ovary for histological examinations and the left for quantitative real-time polymerase) were dissected.

Results

Compared to the control group, the PCO group showed significantly lower values for the mean body weight, number of preantral and antral follicles, serum levels of estradiol, luteinizing hormone, testosterone, and follicle-stimulating hormone, and gene expression of TGFB1, GDF9 and BMPR2 (p<0.05). Serum progesterone levels were significantly higher in the PCO animals than in the control group (p<0.05). No significant between-group differences (p>0.05) were found in BMP6 or BMP15 expression.

Conclusion

In animals with EV-induced PCO, the preantral follicles did not develop into antral follicles. In this mouse model, the gene expression of TGFB1, GDF9, and BMPR2 was lower in preantral follicles, which is probably related to the pathologic conditions of PCO. Hypoandrogenism was also detected in this EV-induced murine PCO model.

The impact of isotretinoin on the pituitary-ovarian axis: An interpretative review of the literature

Isotretinoin (13-cis-retinoic acid), a derivative of vitamin A, is used in the treatment of severe acne resulting in sebum suppression induced by sebocyte apoptosis. Isotretinoin treatment is associated with several adverse effects including teratogenicity, hepatotoxicity, and dyslipidemia. Isotretinoin's effects on endocrine systems and its potential role as an endocrine disruptor are not yet adequately investigated. This review presents clinical, endocrine, and molecular evidence showing that isotretinoin treatment adversely affects the pituitary-ovarian axis and enhances the risk of granulosa cell apoptosis reducing follicular reserve. Isotretinoin is associated with pro-apoptotic signaling in sebaceous glands through upregulated expression of p53, forkhead box O transcription factors (FOXO1, FOXO3), and tumor necrosis factor-related apoptosis inducing ligand (TRAIL). Two literature searches including clinical and experimental studies respectively support the hypothesis that isotretinoin's toxicological mode of action on the pituitary-ovarian axis might be caused by over-expressed p53/FOXO1 signaling resulting in gonadotropin suppression and granulosa cell apoptosis. The reduction of follicular reserve by isotretinoin treatment should be especially considered when this drug will be administered for the treatment of acne in post-adolescent women, in whom fertility may be adversely affected. In contrast, isotretinoin treatment may exert beneficial effects in states of hyperandrogenism, especially in patients with polycystic ovary syndrome.

Androgens regulate ovarian gene expression by balancing Ezh2-Jmjd3 mediated H3K27me3 dynamics

Conventionally viewed as male hormone, androgens play a critical role in female fertility. Although androgen receptors (AR) are transcription factors, to date very few direct transcriptional targets of ARs have been identified in the ovary. Using mouse models, this study provides three critical insights about androgen-induced gene regulation in the ovary and its impact on female fertility. First, RNA-sequencing reveals a number of genes and biological processes that were previously not known to be directly regulated by androgens in the ovary. Second, androgens can also influence gene expression by decreasing the tri-methyl mark on lysine 27 of histone3 (H3K27me3), a gene silencing epigenetic mark. ChIP-seq analyses highlight that androgen-induced modulation of H3K27me3 mark within gene bodies, promoters or distal enhancers have a much broader impact on ovarian function than the direct genomic effects of androgens. Third, androgen-induced decrease of H3K27me3 is mediated through (a) inhibiting the expression and activity of Enhancer of Zeste Homologue 2 (EZH2), a histone methyltransferase that promotes tri-methylation of K27 and (b) by inducing the expression of a histone demethylase called Jumonji domain containing protein-3 (JMJD3/KDM6B), responsible for removing the H3K27me3 mark. Androgens through the PI3K/Akt pathway, in a transcription-independent fashion, increase hypoxia-inducible factor 1 alpha (HIF1α) protein levels, which in turn induce JMJD3 expression. Furthermore, proof of concept studies involving in vivo knockdown of Ar in the ovary and ovarian (granulosa) cell-specific Ar knockout mouse model show that ARs regulate the expression of key ovarian genes through modulation of H3K27me3.

Serum testosterone levels are positively associated with serum anti-mullerian hormone levels in infertile women

Anti-Mullerian hormone (AMH) and testosterone (T) both play distinct roles in the early stages of folliculogenesis. However, the relationship between serum T and AMH levels is poorly understood. This study aimed to investigate the association between serum T and AMH levels in infertile women. A total of 1935 infertile women aged 20-46 years were included in the cross-sectional study and divided into four quartile groups (Q1 to Q4) based on serum T levels. Compared to the subjects in the highest T quartile (Q4), those in the lowest T quartile (Q1) showed significantly lower AMH levels. After adjustment for age, body weight, body mass index and FSH, increasing T quartile categories were associated with higher AMH levels. Binary logistic regression analyses revealed that the odds for the risk of diminished ovarian reserve (DOR) were 11.44-fold higher in Q1 than in Q4 and the odds for the risk of excess ovarian reserve (EOR) were 10.41-fold higher in Q4 than in Q1. Our data show that serum T levels are positively associated with serum AMH levels and suggest that androgen insufficiency may be a potential risk factor for DOR; androgen excess may lead to EOR in infertile women.

The Relationships Between Serum DHEA-S and AMH Levels in Infertile Women: A Retrospective Cross-Sectional Study

The relationship between serum dehydroepiandrosterone sulphate (DHEA-S) and anti-Mullerian hormone (AMH) levels has not been fully established. Therefore, we performed a large-scale cross-sectional study to investigate the association between serum DHEA-S and AMH levels. The study included a total of 2155 infertile women aged 20 to 46 years who were divided into four quartile groups (Q1 to Q4) based on serum DHEA-S levels. We found that there was a weak positive association between serum DHEA-S and AMH levels in infertile women (r = 0.190, p < 0.001). After adjusting for potential confounders, serum DHEA-S levels positively correlated with serum AMH levels in infertile women (β = 0.103, p < 0.001). Infertile women in the highest DHEA-S quartile category (Q4) showed significantly higher serum AMH levels (p < 0.001) compared with women in the lowest DHEA-S quartile category (Q1). The serum AMH levels significantly increased across increasing DHEA-S quartile categories in infertile women (p = 0.014) using generalized linear models after adjustment for potential confounders. Our data show that serum DHEA-S levels are positively associated with serum AMH levels.

Dihydrotestosterone regulates oestrogen secretion, oestrogen receptor expression, and apoptosis in granulosa cells during antral follicle development

Dihydrotestosterone (DHT) is involved in the development of preantral follicles. However, the effect of DHT on the development of antral follicles has yet to be fully investigated. Herein, we used enzyme-linked immunosorbent assays, immunofluorescence assays, quantitative real time-polymerase chain reaction, immunohistochemical staining, and western blotting to investigate the effect of DHT on antral follicle development. First, we detected the concentration of DHT and the expression of the androgen receptor (AR) in different antral follicles. Second, multiple DHT concentration (10^-10-10^-7 M) were added to granulosa cells cultured in vitro to examine the influence of DHT on AR expression. Third, to study changes in the expression of oestrogen (E2) synthase and receptors during the development of antral follicles, we divided them according to their diameters into small (≤ 2 mm), medium (2-5 mm), and large (≥ 5 mm) groups. Fourth, we added DHT (10^-8 M) and flutamide (Flu, 10^-7 M) to granulosa cells to determine whether DHT regulates the expression of cytochrome P450 aromatase (CYP19A1) and the associated receptors through the AR pathway. Fifth, we tested the effect of DHT and Flu on the expression of apoptotic genes and proteins in granulosa cells. We found that AR was expressed in sheep antral follicle granulosa cells and was regulated by DHT. During antral follicle development, the concentration of E2 and the expression of CYP19A1 and E2 receptors significantly increased in granulosa cells. DHT influenced this increase, at least partially, through the AR. Moreover, DHT regulated the expression of apoptotic genes and proteins through the AR. Our study expands our knowledge on the regulatory mechanism of DHT in antral follicle development and guides further research on the androgen regulation of ovarian function.

Vascular remodeling by placenta-derived mesenchymal stem cells restores ovarian function in ovariectomized rat model via the VEGF pathway

Angiogenesis plays an important role in damaged organ or tissue and cell regeneration and ovarian development and function. Primary ovarian insufficiency (POI) is a prevalent pathology in women under 40. Conventional treatment for POI involves hormone therapy. However, due to its side effects, an alternative approach is desirable. Human mesenchymal stem cells (MSCs) from various sources restore ovarian function; however, they have many limitations as stem cell sources. Therefore, it is desirable to study the efficacy of placenta-derived MSCs (PD-MSCs), which possess many advantages over other MSCs, in a rat model of ovarian dysfunction. Here, we investigated the restorative effect of PD-MSCs on injured ovaries in ovariectomized (OVX) rats and the ability of intravenous transplantation (Tx) of PD-MSCs (5 × 105) to enhance ovarian vasculature and follicular development. ELISA analysis of serum revealed that compared to the non-transplantation (NTx) group, the Tx group showed significantly increased levels of anti-Müllerian hormone, follicle stimulating hormone, and estradiol (E2) (*P < 0.05). In addition, histological analysis showed more mature follicles and less atresia and restoration of expanded blood vessels in the ovaries of the OVX PD-MSC Tx group than those of the NTx group (*P < 0.05). Furthermore, folliculogenesis-related gene expression was also significantly increased in the PD-MSC Tx group (*P < 0.05). Vascular endothelial growth factor (VEGF) and VEGF receptor 2 expressions were increased in the ovaries of the OVX PD-MSC Tx group compared to the NTx group through PI3K/AKT/mTOR and GSK3β/β-catenin pathway activation. Interestingly, ex vivo cocultivation of damaged ovaries and PD-MSCs or treatment with recombinant VEGF (50 ng/ml) increased folliculogenic factors and VEGF signaling pathways. Notably, compared to recombinant VEGF, PD-MSCs significantly increased folliculogenesis and angiogenesis (*P < 0.05). These findings suggest that VEGF secreted by PD-MSCs promotes follicular development and ovarian function after OVX through vascular remodeling. Therefore, these results provide fundamental data for understanding the therapeutic effects and mechanism of stem cell therapy based on PD-MSCs and provide a theoretical foundation for their application for obstetrical and gynecological diseases, including infertility and menopause.

The Role of Androgen Supplementation in Women With Diminished Ovarian Reserve: Time to Randomize, Not Meta-Analyze

The management of patients with diminished ovarian reserve (DOR) remains one of the most challenging tasks in IVF clinical practice. Despite the promising results obtained from animal studies regarding the importance of androgens on folliculogenesis, the evidence obtained from clinical studies remains inconclusive. This is mainly due to the lack of an evidence-based methodology applied in the available trials and to the heterogeneity in the inclusion criteria and IVF treatment protocols. In this review, we analyze the available evidence obtained from animal studies and highlight the pitfalls from the clinical studies that prevent us from closing the chapter of this line of research.

Melatonin: Multi-Target Mechanism Against Diminished Ovarian Reserve Based on Network Pharmacology

BACKGROUND

Diminished ovarian reserve (DOR) significantly increases the risk of female infertility and contributes to reproductive technology failure. Recently, the role of melatonin in improving ovarian reserve (OR) has attracted widespread attention. However, details on the pharmacological targets and mechanisms of melatonin-improved OR remain unclear.

OBJECTIVE

A systems pharmacology strategy was proposed to elucidate the potential therapeutic mechanism of melatonin on DOR at the molecular, pathway, and network levels.

METHODS

The systems pharmacological approach consisted of target identification, data integration, network construction, bioinformatics analysis, and molecular docking.

RESULTS

From the molecular perspective, 26 potential therapeutic targets were identified. They participate in biological processes related to DOR development, such as reproductive structure development, epithelial cell proliferation, extrinsic apoptotic signaling pathway, PI3K signaling, among others. Eight hub targets (MAPK1, AKT1, EGFR, HRAS, SRC, ESR1, AR, and ALB) were identified. From the pathway level, 17 significant pathways, including the PI3K-Akt signaling pathway and the estrogen signaling pathway, were identified. In addition, the 17 signaling pathways interacted with the 26 potential therapeutic targets to form 4 functional modules. From the network point of view, by regulating five target subnetworks (aging, cell growth and death, development and regeneration, endocrine and immune systems), melatonin could exhibit anti-aging, anti-apoptosis, endocrine, and immune system regulation effects. The molecular docking results showed that melatonin bound well to all hub targets.

CONCLUSION

This study systematically and intuitively illustrated the possible pharmacological mechanisms of OR improvement by melatonin through anti-aging, anti-apoptosis, endocrine, and immune system regulation effects.

Nuclear receptors: Key regulators of somatic cell functions in the ovulatory process

The development of the ovarian follicle to its culmination by ovulation is an essential element of fertility. The final stages of ovarian follicular growth are characterized by granulosa cell proliferation and differentiation, and steroid synthesis under the influence of follicle-stimulating hormone (FSH). The result is a population of granulosa cells poised to respond to the ovulatory surge of luteinizing hormone (LH). Members of the nuclear receptor superfamily of transcription factors play indispensable roles in the regulation of these events. The key regulators of the final stages of follicular growth that precede ovulation from this family include the estrogen receptor beta (ESR2) and the androgen receptor (AR), with additional roles for others, including steroidogenic factor-1 (SF-1) and liver receptor homolog-1 (LRH-1). Following the LH surge, the mural and cumulus granulosa cells undergo rapid changes that result in expansion of the cumulus layer, and a shift in ovarian steroid hormone biosynthesis from estradiol to progesterone production. The nuclear receptor best associated with these events is LRH-1. Inadequate cumulus expansion is also observed in the absence of AR and ESR2, but not the progesterone receptor (PGR). The terminal stages of ovulation are regulated by PGR, which increases the abundance of the proteases that are directly responsible for rupture. It further regulates the prostaglandins and cytokines associated with the inflammatory-like characteristics of ovulation. LRH-1 regulates PGR, and is also a key regulator of steroidogenesis, cellular proliferation, and cellular migration, and cytoskeletal remodeling. In summary, nuclear receptors are among the panoply of transcriptional regulators with roles in ovulation, and several are necessary for normal ovarian function.

The optimized research of the in vitro culture of preantral follicles in mice

OBJECTIVE

Efficiency of preantral follicle culture in vitro is low and is dependent on species, development stage, and follicle-stimulating hormone (FSH) concentration. Here, we optimized the preantral follicle in vitro culture system in mice.

METHODS

The primary follicles (PM follicles, 80-100 μm diameter ) and early secondary follicles (ES follicles, 110-130 μm diameter) isolated from 14-day female mice were cultured in mediums containing 10 mIU/mL or 100 mIU/mL r-FSH. The follicle growth and oocyte maturation were observed. Estradiol (E2) was detected by ELISA. FSH receptor (FSHR), Ki-67, 3β-HSD, CYP17, and CYP19 levels were detected by immunofluorescence and Western blot.

RESULTS

The antrum formation and oocyte maturation rates of ES follicles were significantly higher than those of PM follicles (P < .05). They were also significantly higher in ES follicles with 100 mIU/mL r-FSH than with 10 mIU/mL r-FSH (P < .05). A higher FSHR level was found in ES follicles. Meanwhile, with 10 mIU/mL r-FSH, the ES follicles exhibited a pattern of flat growth, whereas a pattern of stereoscopic spatial growth was observed with 100 mIU/mL r-FSH. The 100 mIU/mL r-FSH stimulated granulosa cell proliferation more significantly than 10 mIU/mL r-FSH. Moreover, FSH significantly promoted ES follicle granulosa cell proliferation compared to PM follicular granulosa cells. The secretion of E2 and the expressions of 3β-HSD, CYP 17, and CYP 19 in ES follicles with 100 mIU/mL r-FSH were significantly higher than those with 10 mIU/mL r-FSH.

CONCLUSIONS

The 100 mIU/mL r-FSH ideally promotes the development of ES follicles, whose growth pattern can more reasonably simulate the growth of follicles in vivo.

High DHEAS Level in Girls Is Associated with Earlier Pubertal Maturation and Mild Increase in Androgens throughout Puberty without Affecting Postmenarche Ovarian Morphology

OBJECTIVE

To assess whether the presence of high DHEAS (HD) at 7 years determines different timing, sequence, and rate of pubertal events, and whether it is associated with adrenal and/or ovarian hyperandrogenism and changes in ovarian morphology throughout puberty.

METHODS

In a longitudinal study of 504 girls, clinical evaluation was performed every 6 months after 7 years of age to detect Tanner stages; hormonal and anthropometric measurements were conducted at thelarche (B2), breast Tanner 4 (B4), and 1 year after menarche; ultrasonographic evaluation was also performed after menarche. The girls were classified as HD if their DHEAS level was >42.1 µg/dL (>75th percentile) around 7 years.

RESULTS

HD around 7 years is associated with a younger age at thelarche, pubarche, and menarche. Girls with HD had higher androstenedione and total testosterone levels, and a higher free androgen index (FAI), and lower levels of antimüllerian hormone (AMH) at B2, and higher levels of androstenedione and FAI at B4 and after menarche. All these results were significant even after adjusting for body mass index, age at first DHEAS determination, and birth weight. One year after menarche, polycystic ovarian morphology was detected in 7.6 and 7.3% of the HD and the normal DHEAS group, respectively. Ovarian volume was correlated with AMH, testosterone, androstenedione, and LH but not with DHEAS around 7 years.

CONCLUSION

Prepubertal HD in normal girls was associated with earlier thelarche, pubarche, and menarche, and a mild androgen increase throughout puberty. We believe continuous follow-up of this cohort is important to prospectively address the interrelationships between biochemical adrenarche and early growth as determinants of ovarian function.

The Protective Effect of Testosterone on the Ovarian Reserve During Cyclophosphamide Treatment

Introduction

Cyclophosphamide, which is widely used to treat malignant disease, causes ovarian follicular atresia, which leads to premature ovarian insufficiency. The present study evaluated the protective effect of testosterone in preventing the decline in the ovarian reserve during cyclophosphamide treatment.

Methods

Using the COV434 human granulosa cell line, the protective effect of testosterone against cyclophosphamide was evaluated by immunocytochemistry, Western blotting and an MTS assay. The follicles in mouse ovaries and serum anti-Mullerian hormone were also assessed to evaluate the effects of testosterone.

Results

Testosterone suppressed the decrease in cell viability and apoptosis caused by cyclophosphamide treatment in vitro. In vivo, the number of atretic follicles in the mouse ovary was significantly lower in the testosterone plus cyclophosphamide group than in the cyclophosphamide alone group (p=0.03). The serum anti-Mullerian hormone was significantly higher in the testosterone plus cyclophosphamide group than in the cyclophosphamide alone group (16.2 [9.7–22.6]) vs 11.2 [8.9–12.1], p<0.01). The rate of cleaved Caspase-3 expression in the testosterone plus cyclophosphamide group was lower than that in the cyclophosphamide alone group (28.4% vs 48.6%, p=0.03).

Conclusion

These findings indicated that testosterone has the potential to prevent ovarian damage induced by cyclophosphamide by protecting granulosa cells from cyclophosphamide-induced apoptosis.

Identifying genes associated with the development of human polycystic ovary syndrome

The pathophysiology of polycystic ovary syndrome (PCOS) is confusing until today as it is a multifactorial endocrine disorder. It is presented with altered gonadotropin levels, bulky multi-follicular ovaries, infertility, and obesity. This complex pathophysiology is linked with insulin resistance and hyperandrogenism. Hyperandrogenemia significantly contributes towards cosmetic anomalies including hirsutism, acne, and alopecia in the PCOS women. The preexisting insulin resistance in women with PCOS is likely to aggravate the increased levels of androgen. The review findings have shown that in the steroidogenic pathway, ovarian steroidogenesis patterns classify mainly towards the hypertrophy of theca cells along with alteration in the expression of key enzymes. The association of polymorphisms in genes encoding the process of an intricate cascade of steroidogenesis is delineated. The emergence of an unanimously accepted genetic marker for susceptible PCOS was affected based on inconsistent findings. The present study has provided a comprehensive summary of the impact of polymorphisms among the common androgen-related genes to govern the genetic predisposition.

Neonatal Exposure to Agonists and Antagonists of Sex Steroid Receptors Affects AMH and FSH Plasma Level and Their Receptors Expression in the Adult Pig Ovary

Simple Summary

The ovarian development and the establishment of ovarian reserve during fetal and/or neonatal life is critical for future reproductive success. Many environmental chemicals are known to negatively affect development and physiology of human and animal ovaries by interfering with endocrine systems, resulting in aberrant reproductive functions. The present study shows the long-term impact of neonatal exposure to agonists and antagonists of sex steroid receptors on AMH and FSH signalling in the ovary of adult pigs. Our findings suggest alteration in ovarian follicle recruitment from ovarian reserve arising from neonatal disruption of androgen/estrogen signalling induced by environmental endocrine active compounds. Everyday use of many endocrine disruptors is already prohibited after their harmful impacts on normal physiology have become known. Nevertheless, market introduction of new chemicals with potential deleterious influence on reproductive physiology has continued. Our outcomes confirm that a neonatal window plays an essential role in the physiological programming of ovarian function in adult pigs. The influence of environmental chemicals on this critical neonatal window needs to be investigated in order to gain a comprehensive view of deleterious interactions between endocrine disrupting chemicals and ovarian function.

Abstract

In this study piglets were injected with testosterone propionate (TP, an androgen), flutamide (FLU, an antiandrogen), 4-tert-octylphenol (OP, an estrogenic compound), ICI 182,780 (ICI, an antiestrogen) or corn oil (controls) between postnatal days 1 and 10 (N = 5/group). Then plasma anti-Müllerian hormone (AMH) and follicle stimulating hormone (FSH) concentration and the expression of their receptors were examined in the adult pig ovary. TP and FLU decreased plasma AMH and FSH concentration. In preantral follicles, TP resulted in upregulation of AMHR2 and FSHR expression, but decreased AMH protein abundance. FLU upregulated AMHR2 expression, while OP increased FSHR mRNA. In small antral follicles, OP upregulated ACVR1 and BMPR1A expression, while FLU increased BMPR1A mRNA. FLU and ICI resulted in upregulation of AMHR2 expression. TP and FLU upregulated AMH expression, while it was downregulated in response to OP or ICI. Moreover, OP and ICI resulted in downregulation of FSHR expression, while FLU decreased FSHR protein abundance. In conclusion, neonatal exposure to either agonist or antagonist of androgen receptor affected AMH and FSH signalling systems in preantral follicles. In small antral follicles these systems were influenced by compounds with estrogenic, antiestrogenic, and antiandrogenic activity. Consequently, these hormonal agents may cause an accelerated recruitment of primordial follicles and affect the cycling recruitment of small antral follicles in pigs.

Gene Expression in Granulosa Cells From Small Antral Follicles From Women With or Without Polycystic Ovaries

CONTEXT

Polycystic ovary syndrome (PCOS) is the most common cause of anovulation. A key feature of PCOS is arrest of follicles at the small- to medium-sized antral stage.

OBJECTIVE AND DESIGN

To provide further insight into the mechanism of follicle arrest in PCOS, we profiled (i) gonadotropin receptors; (ii) characteristics of aberrant steroidogenesis; and (iii) expression of anti-Müllerian hormone (AMH) and its receptor in granulosa cells (GCs) from unstimulated, human small antral follicles (hSAFs) and from granulosa lutein cells (GLCs).

SETTING

GCs from hSAFs were collected at the time of cryopreservation of ovarian tissue for fertility preservation and GLCs collected during oocyte aspiration before in vitro fertilization/intracytoplasmic sperm injection.

PARTICIPANTS

We collected hSAF GCs from 31 women (98 follicles): 10 with polycystic ovaries (PCO) and 21 without. GLCs were collected from 6 women with PCOS and 6 controls undergoing IVF.

MAIN OUTCOME MEASURES

Expression of the following genes: LHCGR, FSHR, AR, INSR, HSD3B2, CYP11A1, CYP19, STAR, AMH, AMHR2, FST, INHBA, INHBB in GCs and GLCs were compared between women with PCO and controls.

RESULTS

GCs in hSAFs from women with PCO showed higher expression of LHCGR in a subset (20%) of follicles. Expression of FSHR (P < 0.05), AR (P < 0.05), and CYP11A1 (P < 0.05) was lower, and expression of CYP19A1 (P < 0.05), STAR (P < 0.05), HSD3B2 (P = NS), and INHBA (P < 0.05) was higher in PCO GCs. Gene expression in GL cells differed between women with and without PCOS but also differed from that in GCs.

CONCLUSIONS

Follicle arrest in PCO is characterized in GCs by differential regulation of key genes involved in follicle growth and function.

Features of the fetal gonad in androgen synthesis in the postpubertal testis are preserved in complete androgen insensitivity syndrome due to a novel genetic splice site donor variant in androgen receptor gene intron 1

Mutations in the X-linked androgen receptor (AR) gene cause complete androgen insensitivity syndrome (CAIS). CAIS may cause congenital sexual development disorder, which frequently develops into testicular tumors. Here, we describe a novel splice-site intron 1 mutation in AR leading to improper splicing and AR protein absence in CAIS gonads. We characterized a patient's postpubertal gonadal steroidogenic enzyme expression profile. Localization of both CYP11A1 and CYP17A1 enzymes was restricted to both Leydig tumor cells and adjacent to tumor gonadal tissues. Sertoli cells of the CAIS gonad showed abundant HSD17B3 protein, which is an adult Leydig cell marker that enables the conversion of androstenedione to testosterone. Such HSD17B3 expression is typical for fetal-type Sertoli cells in rodents. The postpubertal CAIS gonad of our patient was completely devoid of androgen signaling pathway activity. Plausibly, the postpubertal Leydig cells consisted of two distinct cell populations: postpubertal fetal-type Leydig cells that persisted as androgen-independent cells and immature adult Leydig cells that failed to differentiate. Taken together, in this CAIS postpubertal testis, both Leydig and fetal-type Sertoli cells participated in testosterone production. Our results indicate the importance of molecular analysis as well as the characterization of steroidogenic enzyme profiling in the CAIS patient's gonad.

CircINHA resists granulosa cell apoptosis by upregulating CTGF as a ceRNA of miR-10a-5p in pig ovarian follicles

Mammalian ovarian follicular atresia is a complex and fine-regulated biological process with active involvement of connective tissue growth factor (CTGF). The emergence of studies of endogenous non-coding RNAs has raised a new aspect for exploration of the regulatory mechanisms involved in follicular atresia. Here, we aimed to illustrate a circRNA involved in the CTGF regulatory pathway during the apoptosis and follicular atresia of pig granulosa cells (GCs). We first detected a decreased expression pattern of CTGF during follicular atresia using IHC, FISH and qRT-PCR and confirmed the anti-apoptosis effect of CTGF in GCs in vitro by CTGF siRNA knockdown. Then, we used a dual luciferase activity assay to demonstrate CTGF as a direct functional target of miR-10a-5p, which was upregulated in atresic follicles and promoted the apoptosis of GCs in vitro. The negative effect of miR-10a-5p on GC viability was confirmed by cell cycle assays, cell proliferation/apoptosis assays and the WB detection of marker proteins. More importantly, we identified a novel circRNA, termed circINHA, that was downregulated during atresia in ovarian follicles, and we confirmed a direct interaction between miR-10a-5p and circINHA. Finally, we demonstrated that circINHA promoted GCs proliferation and inhibited GCs apoptosis via CTGF as a competing endogenous RNA (ceRNA) that directly bound to miR-10a-5p. Taken together, this study provides evidence for the circINHA/miR-10a-5p/CTGF regulatory pathway in follicular GC apoptosis and provides novel insights into the role of circRNAs in the modulation of ovarian physiological functions.

Physiological and Pathological Androgen Actions in the Ovary

Androgens, although traditionally thought to be male sex steroids, play important roles in female reproduction, both in healthy and pathological states. This mini-review focuses on recent advances in our knowledge of the role of androgens in the ovary. Androgen receptor (AR) is expressed in oocytes, granulosa cells, and theca cells, and is temporally regulated during follicular development. Mouse knockout studies have shown that AR expression in granulosa cells is critical for normal follicular development and subsequent ovulation. In addition, androgens are involved in regulating dynamic changes in ovarian steroidogenesis that are critical for normal cycling. Androgen effects on follicle development have been incorporated into clinical practice in women with diminished ovarian reserve, albeit with limited success in available literature. At the other extreme, androgen excess leads to disordered follicle development and anovulatory infertility known as polycystic ovary syndrome (PCOS), with studies suggesting that theca cell AR may mediate many of these negative effects. Finally, both prenatal and postnatal animal models of androgen excess have been developed and are being used to study the pathophysiology of PCOS both within the ovary and with regard to overall metabolic health. Taken together, current scientific consensus is that a careful balance of androgen activity in the ovary is necessary for reproductive health in women.

Expression of genes controlling steroid metabolism and action in granulosa-lutein cells of women with polycystic ovaries

INTRODUCTION

Aberrant function of granulosa cells has been implicated in the pathophysiology of PCOS.

MATERIALS & METHODS

Granulosa lutein (GL) cells were collected during oocyte retrieval for IVF/ICSI. RT-qPCR was used to compare gene expression between 12 control women, 12 with ovulatory PCO and 12 with anovulatory PCOS. To examine which genes are directly regulated by androgens, GL cells from an additional 12 control women were treated in-vitro with 10 nM dihydrotestosterone (DHT).

RESULTS

GL cells from women with PCOS showed reduced expression of CYP11A1 3-fold (p = 0.005), HSD17B1 1.8-fold (p = 0.02) and increased expression of SULT1E1 7-fold (p = 0.0003). Similar results were seen in ovulatory women with PCO. GL cells treated with 10 nM DHT showed a 4-fold (p = 0.03) increase in expression of SULT1E1 and a 5-fold reduction in SRD5A1 (p = 0.03).

CONCLUSIONS

These findings support the notion that aberrant regulation of steroid metabolism or action play a part in ovarian dysfunction in PCOS.

Androgen potentiates the expression of FSH receptor and supports preantral follicle development in mice

Hyperandrogenism is one of the cardinal symptoms in polycystic ovary syndrome and plays a key role in the pathogenesis of polycystic ovary syndrome. However, the precise effects and mechanisms of excess androgen during follicular development are still unclear. Here we investigated the effects of androgen on mouse follicle development in vitro. Androgen did not affect the growth of follicles smaller than 160–180 μm in the presence of follicle-stimulating hormone (FSH). However, in the presence of low FSH, androgen supported the growth of follicles larger than 160–180 μm, a size at which growing follicles acquire FSH-dependency. Androgen did not change the mRNA expression of various growth-promoting factors but did increase mRNA expression of the FSH receptor. We suggest that androgen has a positive impact on follicle development by augmentation of the actions of FSH. Therefore, FSH-responsive but FSH-independent follicles grow in the presence of a certain level of FSH or androgen, and androgen compensates for FSH deficiency in FSH-dependent follicles.

A Hyperandrogenic Environment Causes Intrinsic Defects That Are Detrimental to Follicular Dynamics in a PCOS Mouse Model

Polycystic ovary syndrome (PCOS) is a common cause of female infertility. Hyperandrogenism is both a major symptom and key diagnostic trait of PCOS; however, the direct impact of this androgen excess on ovarian dynamics is unclear. By combining a DHT-induced PCOS mouse model with an ex vivo follicle culture system, we investigated the impact of hyperandrogenism on ovarian function. Ovaries from PCOS mice exhibited the characteristic polycystic ovary morphology with numerous large cystic follicles and no corpora lutea present. Isolation and individual culture of preantral and antral follicles from PCOS mice resulted in slower growth rates during 5 days compared with the follicles isolated from control mice (P < 0.01). In contrast, preovulatory follicles from PCOS mice exhibited a significant increase in growth rate compared with controls (P < 0.01). Preantral follicles from PCOS ovaries maintained comparable follicular health as control follicles, but antral and preovulatory PCOS follicles exhibited reduced follicle health (P < 0.01) and survival rates (P < 0.01). Compared with controls, PCOS females also exhibited a poorer response to hyperstimulation (P < 0.01), impaired oocyte function evident by increased levels of reactive oxygen species (P < 0.01), and a reduction in on-time embryo development (P < 0.01). These results demonstrate that prolonged exposure to androgen excess leads to aberrant follicle development, which persists even after removal from the hyperandrogenic environment, causing perturbed follicular developmental trajectories. These findings indicate that an in vivo hyperandrogenic environment in patients with PCOS may intrinsically induce detrimental effects on follicles and oocytes.

Distinctive subpopulations of the intestinal microbiota are present in women with unexplained chronic anovulation

RESEARCH QUESTION

Do gut microbiota associate with the ovulatory cycle in women showing normogonadotrophic anovulation? In humans, the gut microbiota affects diverse physiological functions and dysbiosis (microbial imbalance) may lead to pathological syndromes. However, there is comparatively little information on the relevance of gut microbiota to reproductive functions in women. Here, a group of women with idiopathic chronic anovulation were examined, who do not exhibit any apparent endocrinological disorder, as they are suitable for investigating the relationship between intestinal bacteria and ovulatory disorders.

DESIGN

A prospective observational cohort study was performed on two groups of women who did not exhibit apparent endocrinological disorders but showed either irregular menstrual cycles (IMC group) or normal menstrual cycles (controls). The bacterial composition of faeces from rectal swabs from the women was analysed using next-generation sequencing based on bacterial 16SrRNA genes.

RESULTS

A metagenomic analysis indicated that the two groups of women had significant differences in 28 bacterial taxa in their faeces. Prevotella-enriched microbiomes were more abundant in the IMC group, whereas Clostridiales, Ruminococcus and Lachnospiraceae (butyrate-producing bacteria) were present at lower levels in the IMC group.

CONCLUSIONS

Distinctive subpopulations of intestinal microbiota were identified in women with unexplained chronic anovulation. The results indicate that gut microbiota could be associated with ovarian functions.

Direct actions of androgen, estrogen and anti-Müllerian hormone on primate secondary follicle development in the absence of FSH in vitro

STUDY QUESTION

What are effects of androgen, estrogen and anti-Müllerian hormone (AMH), independent of FSH action, on the development and function of primate follicles from the preantral to small antral stage in vitro?

SUMMARY ANSWER

Androgen and estrogen, but not AMH, promote follicle survival and growth in vitro, in the absence of FSH. However, their growth-promoting effects are limited to the preantral to early antral stage.

WHAT IS KNOWN ALREADY

FSH supports primate preantral follicle development in vitro. Androgen and estrogen augment follicle survival and growth in the presence of FSH during culture.

STUDY DESIGN SIZE, DURATION

Nonhuman primate model; randomized, control versus treatment groups. Rhesus macaque (n = 6) secondary follicles (n = 24 per animal per treatment group) were cultured for 5 weeks.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Follicles were encapsulated in 0.25% (w/v) alginate and cultured individually in modified alpha minimum essential media with (i) FSH (1 ng/ml; control), (ii) no FSH, (iii) no FSH + estradiol (E2; 100 pg/ml)/dihydrotestosterone (DHT; 50 ng/ml) and (iv) no FSH + AMH (50 ng/ml). In a second experiment, follicles were cultured with (i) FSH (1 ng/ml), (ii) no FSH, (iii) no FSH + E2 (1 ng/ml), (iv) no FSH + DHT (50 ng/ml) and (v) no FSH + E2/DHT. Follicle survival, antrum formation and growth pattern were evaluated. Progesterone (P4), E2 and AMH concentrations in culture media were measured.

MAIN RESULTS AND THE ROLE OF CHANCE

In the first experiment, FSH deprivation significantly decreased (P < 0.05) follicle survival rates in the no FSH group (16 ± 5%), compared to CTRL (66 ± 9%). E2/DHT (49 ± 5%), but not AMH (27 ± 8%), restored follicle survival rate to the CTRL level. Similarly, antrum formation rates were higher (P < 0.05) in CTRL (56 ± 6%) and E2/DHT groups (54 ± 14%), compared to no FSH (0 ± 0%) and AMH (11 ± 11%) groups. However, follicle growth rate after antrum formation and follicle diameter at week 5 was reduced (P < 0.05) in the E2/DHT group (405 ± 25 μm), compared to CTRL (522 ± 29 μm). Indeed, the proportion of fast-grow follicles at week 5 was higher in CTRL (29% ± 5), compared to E2/DHT group (10 ± 3%). No fast-grow follicles were observed in no FSH and AMH groups. AMH levels at week 3 remained similar in all groups. However, media concentrations of P4 and E2 at week 5 were lower (P < 0.05, undetectable) in no FSH, E2/DHT and AMH groups, compared to CTRL (P4 = 93 ± 10 ng/ml; E2 = 4 ± 1 ng/ml). In the second experiment, FSH depletion diminished follicle survival rate (66 ± 8% in control versus 45 ± 9% in no FSH, P = 0.034). E2 plus DHT (31.5 ± 11%) or DHT alone (69 ± 9%) restored follicle survival rate to the control (FSH) level as expected. Also, E2 plus DHT or DHT alone improved antrum formation rate. However, in the absence of FSH, E2 plus DHT or DHT alone did not support growth, in terms of follicle diameter, or steroid (P4 or E2) production after the antral stage.

LIMITATIONS REASONS FOR CAUTION

This study is limited to in vitro effects of E2, DHT and AMH during the interval from the secondary to small antral stage of macaque follicular development. In addition, the primate follicle pool is heterogeneous and differs between animals; therefore, even though only secondary follicles were selected, follicle growth and developmental outcomes might differ from one animal to another.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides novel information on the possible actions of estrogen and androgen during early follicular development in primates. Our results suggest that sequential exposure of preantral follicles to local factors, e.g. E2 and DHT, followed by gonadotropin once the follicle reaches the antral stage, may better mimic primate folliculogenesis in vivo.

STUDY FUNDING/COMPETING INTEREST(S)

Research reported in this publication was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Center for Translational Research on Reproduction and Infertility 5P50HD071836, and the NIH Primate Centers Program 8P510D011092. There are no conflicts of interest.

Dehydroepiandrosterone (DHEA) supplementation improves in vitro fertilization outcomes of poor ovarian responders, especially in women with low serum concentration of DHEA-S: a retrospective cohort study

BACKGROUND

Dehydroepiandrosterone (DHEA) is now widely used as an adjuvant for in vitro fertilization (IVF) cycles in poor ovarian responders (PORs). Several studies showed that DHEA supplementation could improve IVF outcomes of PORs. However, most of the PORs do not respond to DHEA clinically. Therefore, the aim of this study is to confirm the beneficial effects of DHEA on IVF outcomes of PORs and to investigate which subgroups of PORs can best benefit from DHEA supplementation.

METHODS

This retrospective cohort study was performed between January 2015 and December 2017. A total of 151 PORs who fulfilled the Bologna criteria and underwent IVF cycles with the gonadotropin-releasing hormone antagonist protocol were identified. The study group (n = 67) received 90 mg of DHEA daily for an average of 3 months before the IVF cycles. The control group (n = 84) underwent the IVF cycles without DHEA pretreatment. The basic and cycle characteristics and IVF outcomes between the two groups were compared using independent t-tests, Chi-Square tests and binary logistic regression.

RESULTS

The study and control groups did not show significant differences in terms of basic characteristics. The study group demonstrated a significantly greater number of retrieved oocytes, metaphase II oocytes, fertilized oocytes, day 3 embryos and top-quality embryos at day 3 and a higher clinical pregnancy rate, ongoing pregnancy rate and live birth rate than those measures in the control group. The multivariate analysis revealed that DHEA supplementation was positively associated with clinical pregnancy rate (OR = 4.93, 95% CI 1.68-14.43, p = 0.004). Additionally, in the study group, the multivariate analysis showed that serum dehydroepiandrosterone-sulfate (DHEA-S) levels < 180 μg/dl were significantly associated with a rate of retrieved oocytes > 3 (OR = 5.92, 95% CI 1.48-23.26, p = 0.012).

CONCLUSIONS

DHEA supplementation improves IVF outcomes of PORs. In PORs with DHEA pretreatment, women with lower DHEA-S level may have greater possibility of attaining more than 3 oocytes.

The VEGF and PEDF levels in the follicular fluid of patients co- treated with LETROZOLE and gonadotropins during the stimulation cycle

BACKGROUND

Previous studies have shown that androgens, in addition to serving as precursors for ovarian estrogen synthesis, also have a fundamental role in primate ovarian follicular development by augmentation of FSH receptor expression on granulosa cells. Recent studies have shown that aromatase inhibitor, letrozole, improves ovarian response to FSH in normal and poor responder patients, possibly by increasing intraovarian androgen levels. Studies in mice also showed an effect of letrozole to increase pigment epithelium-derived factor (PEDF) and to lower vascular epithelial growth factor (VEGF), which might be expected to reduce the risk of ovarian hyperstimulation syndrome (OHSS) with stimulation. The aim of this study was to compare the VEGF and PEDF levels in the follicular fluids of normal responders treated with letrozole and gonadotropins during the ovarian stimulation with patients treated with gonadotropins only.

METHODS

A single center, prospective clinical trial. We collected follicular fluid from 26 patients, on a GnRH antagonist protocol, dual triggered with hCG and GnRH agonist. The patients in one group were co-treated with letrozole and gonadotropins during the ovarian stimulation and the patients in the other group were treated with gonadotropins only. VEGF, PEDF, estrogen, progesterone and testosterone levels were measured by ELISA kits.

RESULTS

The age of the patients, the total dose of gonadotropins and the number of oocytes were comparable between the two groups. In the follicular fluid, the estrogen levels (2209 nmol/l vs. 3280 nmol/l, p = 0.02) were significantly decreased, and the testosterone levels (246.5 nmol/l vs. 40.7 nmol/l, p < 0.001) were significantly increased in the letrozole group compared to the gonadotropin only group. The progesterone levels (21.4 μmol/l vs. 17.5 p = NS) were comparable between the two groups. The VEGF levels (2992 pg/ml vs. 1812 pg/ml p = 0.02) were significantly increased and the PEDF levels (9.7 ng/ml vs 17.3 ng/ml p < 0.001) were significantly decreased in the letrozole group.

CONCLUSIONS

Opposite to observations in the mouse, we found that VEGF levels were increased and PEDF levels were decreased in the follicular fluid in patients treated with letrozole during the stimulation cycles. Further investigation is required to determine if patients treated with letrozole during the IVF stimulation protocol are at increased risk for developing OHSS as a result of these findings.

Accelerated Episodic Luteinizing Hormone Release Accompanies Blunted Progesterone Regulation in PCOS-like Female Rhesus Monkeys (Macaca Mulatta) Exposed to Testosterone during Early-to-Mid Gestation

BACKGROUND/AIMS

Ovarian theca cell hyperandrogenism in women with polycystic ovary syndrome (PCOS) is compounded by androgen receptor-mediated impairment of estradiol and progesterone negative feedback regulation of episodic luteinizing hormone (LH) release. The resultant LH hypersecretion, likely the product of accelerated episodic release of gonadotropin-releasing hormone (GnRH) from the median eminence of the hypothalamus, hyperstimulates ovarian theca cell steroidogenesis, enabling testosterone (T) and androstenedione excess. Prenatally androgenized (PA) female monkeys exposed to fetal male levels of T during early-to-mid gestation, when adult, demonstrate PCOS-like traits, including high T and LH levels. This study tests the hypothesis that progesterone resistance-associated acceleration in episodic LH release contributes to PA monkey LH excess.

METHODS

A total of 4 PA and 3 regularly cycling, healthy control adult female rhesus monkeys of comparable age and body mass index underwent (1) a 10 h, frequent intravenous sampling assessment for LH episodic release, immediately followed by (2) IV infusion of exogenous GnRH to quantify continuing pituitary LH responsiveness, and subsequently (3) an SC injection of a progesterone receptor antagonist, mifepristone, to examine LH responses to blockade of progesterone-mediated action.

RESULTS

Compared to controls, the relatively hyperandrogenic PA females exhibited ~100% increase (p = 0.037) in LH pulse frequency, positive correlation of LH pulse amplitude (p = 0.017) with androstenedione, ~100% greater increase (p = 0.034) in acute (0-10 min) LH responses to exogenous GnRH, and an absence (p = 0.008) of modest LH elevation following acute progesterone receptor blockade suggestive of diminished progesterone negative feedback.

CONCLUSION

Such dysregulation of LH release in PCOS-like monkeys implicates impaired feedback control of episodic release of hypothalamic GnRH reminiscent of PCOS neuroendocrinopathy.

Androgen Action in the Ovary

Androgen production by the ovary is an essential requirement for normal cyclical secretion of estradiol but its physiological role extends to important actions on both preantral and antral follicle development, including promotion of granulosa cell proliferation. It is likely only in mature antral follicles that androgens encourage apoptosis and consequent follicle atresia, and this may be an important mechanism to ensure mono-follicular ovulation in primates, including humans. Recent studies have provided new insight into the mechanism of androgen signaling in the ovary which involves both genomic and non-genomic effects that are complementary in effecting a cellular response. In polycystic ovary syndrome, a condition characterized by intra-ovarian androgen excess, aberrant development of both preantral and antral follicles is a salient feature. We present evidence that local action of androgens plays a part in such abnormalities. Finally, we review the role of androgens in follicle atresia and conclude that the effects are part of the normal physiology of follicle maturation.