Academic literature on the topic 'Ovary; human PCOS; KITL'

Abstract STUDY QUESTION Do alterations in pro- and anti-angiogenic estrogen metabolites in follicular fluid (FF) contribute to the follicular growth arrest and anovulation associated with polycystic ovary syndrome (PCOS)? SUMMARY ANSWER FF of PCOS women with anovulation have reduced levels of pro-angiogenic estrogen metabolites (EMs) and vascular endothelial growth factor (VEGF) compared to that of fertile women with regular menstrual cycles, but exogenous gonadotropins increase the pro-angiogenic EMs and VEGF levels in PCOS women. WHAT IS KNOWN ALREADY PCOS is characterized by the arrest of follicular development that leads to chronic anovulation. Follicular arrest is generally associated with elevated plasma levels of luteinizing hormone (LH), androgens and anti-Mullerian hormone (AMH). There is also reduced angiogenesis in the follicles of PCOS women compared to those of normal cycling women. It is known that angiogenesis is a critical factor during follicular development. We and other investigators have explored the role of EMs in ovarian angiogenesis, particularly in human corpus luteum function, showing that 4-hydroxyestrone (4-OHE1) and 16-ketoestradiol (16-kE2) have pro-angiogenic effects while 2-methoxyestradiol (2-ME2) and 2-methoxyestrone (2-ME1) have anti-angiogenic effects. Additionally, 2-hydroxyestradiol (2-OHE2), which is produced in the ovary, has proliferative and pro-angiogenic properties. We hypothesized that EMs could be involved in angiogenesis necessary for ovarian follicular development in fertile women, and that dysregulation of these factors may contribute to follicular arrest in PCOS. The relationship between EMs, VEGF and AMH in the pathophysiology of follicular arrest in PCOS has not been previously studied at a follicular level in anovulatory women without ovulation induction. STUDY DESIGN, SIZE, DURATION This is a comparative experimental study of serum and FF collected from different sized follicles (antral ˂10 mm and dominant ˃16 mm) of women with and without ovarian stimulation. The study included women with regular menstrual cycles who were proven to be fertile (n = 20) and PCOS women with follicular arrest who were candidates for ovarian drilling (n = 17), as well as other patients requiring ovarian stimulation, i.e. control women undergoing IVF for male factor infertility (n = 12) and PCOS women undergoing IVF (n = 17). In vitro studies were carried out on granulosa-lutein cells (GCs) obtained from subsets of women undergoing IVF for male factor infertility (n = 6) and PCOS women undergoing IVF (n = 6). GCs were maintained in culture for up to 6 days. PARTICIPANTS/MATERIALS, SETTING, METHODS Intrafollicular estradiol, estrone and EMs concentrations were determined by high performance liquid chromatography–mass spectrometry. Testosterone in serum was measured by RIA, and LH, FSH and sex hormone-binding globulin in serum were measured with IRMA kits. AMH was determined in serum and FF by enzyme linked immunosorbant assay (ELISA). VEGF levels were measured in FF and conditioned medium by ELISA. Conditioned medium were obtained from cultured GCs. The angiogenic potential was assessed by in vitro angiogenic assays. MAIN RESULTS AND THE ROLE OF CHANCE Pro-angiogenic EMs (4-OHE1, 16-kE2 and 2-OHE2) and VEGF were lower in FF of antral follicles of PCOS women with follicular arrest compared those of fertile women with ovulatory cycles (P < 0.05). In contrast, higher concentrations of AMH were found in FF of antral follicles from PCOS women with follicular arrest compared to those of fertile women with ovulatory cycles (P < 0.05). Exogenous gonadotropins used in IVF increased pro-angiogenic EMs and VEGF production in PCOS women, reaching similar profiles compared to control women receiving gonadotropins in their IVF treatment for male factor infertility. The pro-angiogenic EM 2-OHE2 increased the angiogenic potential and VEGF levels of GCs from PCOS women compared to the basal condition (P < 0.05). These findings suggest that there is a role for pro-angiogenic EMs in the control of follicular VEGF production. LIMITATIONS, REASONS FOR CAUTION The limitations include the possibility that in vitro analysis of GCs might not reflect the in vivo mechanisms involved in the pro-angiogenic action of 2-OHE2 since GCs obtained at the time of oocyte retrieval belong to a very early stage of the luteal phase and might not be representative of GCs during follicular growth. Therefore, our findings do not conclusively rule out the possibility that other in vivo mechanisms also account for defective angiogenesis observed in PCOS. WIDER IMPLICATIONS OF THE FINDINGS The present study highlights the significance of EMs, angiogenic factors and AMH and their interaction in the pathophysiology of follicular development in PCOS. This study provides new insights into the role of pro-angiogenic factors in follicular arrest in PCOS. STUDY FUNDING/COMPETING INTEREST(S) This study was funded by CONICYT/FONDECYT 1140693 and NIH grant R01HD083323. All authors declare no conflict of interest. TRIAL REGISTRATION NUMBER N/A

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders; it is characterized by polycystic ovaries, hyperandrogenism and chronic anovulation. To obtain a global view of those genes that might be involved in the development of this complex clinical disorder, we used recently developed cDNA microarray technology to compare differential gene expressions between normal human ovary and ovaries from PCOS patients. A total of 9216 clones randomly selected from a commercial human ovary cDNA library were screened. Among them, 290 clones showed differential expressions, including 119 known genes and 100 known or unknown expressed sequence tags (ESTs). Among 119 known genes, 88 were upregulated and 31 downregulated in the PCOS ovary, as compared with normal human ovary. These differentially expressed genes are involved in various biologic functions, such as cell division/apoptosis, regulation of gene expression and metabolism, reflecting the complexity of clinical manifestations of PCOS. The molecular characteristics established from our study will further our understanding of the pathogenesis of PCOS and help us to identify new targets for further studies and for the development of new therapeutic interventions.

The prenatally androgenised female rhesus monkey has become a model for polycystic ovary syndrome (PCOS) in women, with early prenatal androgenisation entraining a permanent PCOS-like phenotype characterised by luteinising hormone (LH) hypersecretion due to reduced hypothalamic sensitivity to steroid negative feedback and relative insulin excess associated with increased abdominal adiposity. These combined reproductive and metabolic abnormalities occur in combination with ovarian hyperandrogenism and follicular arrest in adulthood, and with premature follicle differentiation and impaired embryo development during gonadotrophin therapy for in vitro fertilization (IVF). The ability of prenatal androgen excess in fetal rhesus monkeys to entrain multiple organ systems in utero provides evidence that the hormonal environment of intrauterine life programmes target tissue differentiation, raising the possibility that hyperandrogenism in human fetal development promotes PCOS in adulthood. This hypothesis developed in prenatally androgenised female rhesus monkeys, however, also must include data from clinical studies of PCOS to clarify the homology between human and non-human primates in intrafollicular steroidogenesis and its impact on oocyte developmental competency. By doing so, future studies promise to develop new clinical strategies that will lead to improved pregnancy outcome and reduced pregnancy loss in women with disorders of insulin action, including PCOS, obesity and diabetes mellitus.

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women and a major cause of anovulatory infertility. A diagnosis of PCOS is established based the presence of two out of three clinical symptoms, which are criteria accepted by the ESHRE/ASRM (European Society of Human Reproduction and Embryology/American Society for Reproductive Medicine). Gonadotropin-releasing hormone (GnRH) is responsible for the release of luteinizing hormone, and follicle stimulating hormone from the pituitary and contributes a leading role in controlling reproductive function in humans. The goal of this review is to present the current knowledge on neuroendocrine determinations of PCOS. The role of such neurohormones as GnRH, and neuropeptides kisspeptin, neurokinin B, phoenixin-14, and galanin is discussed in this aspect. Additionally, different neurotransmitters (gamma-aminobutyric acid (GABA), glutamate, serotonin, dopamine, and acetylcholine) can also be involved in neuroendocrine etiopathogenesis of PCOS. Studies have shown a persistent rapid GnRH pulse frequency in women with PCOS present during the whole ovulatory cycle. Other studies have proved that patients with PCOS are characterized by higher serum kisspeptin levels. The observations of elevated serum kisspeptin levels in PCOS correspond with the hypothesis that overactivity in the kisspeptin system is responsible for hypothalamic-pituitary-gonadal axis overactivity. In turn, this causes menstrual disorders, hyperandrogenemia and hyperandrogenism. Moreover, abnormal regulation of Neurokinin B (NKB) is also suspected of contributing to PCOS development, while NKB antagonists are used in the treatment of PCOS leading to reduction in Luteinizing hormone (LH) concentration and total testosterone concentration. GnRH secretion is regulated not only by kisspeptin and neurokinin B, but also by other neurohormones, such as phoenixin-14, galanin, and Glucagon-like peptide-1 (GLP-1), that have favorable effects in counteracting the progress of PCOS. A similar process is associated with the neurotransmitters such as GABA, glutamate, serotonin, dopamine, and acetylcholine, as well as the opioid system, which may interfere with secretion of GnRH, and therefore, influence the development and severity of symptoms in PCOS patients. Additional studies are required to explain entire, real mechanisms responsible for PCOS neuroendocrine background.

Polycystic ovary syndrome (PCOS) is a gynecological metabolic and endocrine disorder with uncertain etiology. To understand the etiology of PCOS or the evaluation of various therapeutic agents, different animal models have been introduced. Considering this fact that is difficult to develop an animal model that mimics all aspects of this syndrome, but, similarity of biological, anatomical, and/or biochemical features of animal model to the human PCOS phenotypes can increase its application. This review paper evaluates the recently researched animal models and introduced the best models for different research purposes in PCOS studies. During January 2013 to January 2017, 162 studies were identified which applied various kinds of animal models of PCOS including rodent, primate, ruminant and fish. Between these models, prenatal and pre-pubertal androgen rat models and then prenatal androgen mouse model have been studied in detail than others. The comparison of main features of these models with women PCOS demonstrates higher similarity of these three models to human conditions. Thereafter, letrozole models can be recommended for the investigation of various aspects of PCOS. Interestingly, similarity of PCOS features of post-pubertal insulin and human chorionic gonadotropin rat models with women PCOS were considerable which can make it as a good choice for future investigations.

Polycystic ovary syndrome (PCOS) is an inherent ovarian dysfunction. It is a common health problem that can affect teen girls and young women. PCOS is characterized by hyperandrogenism, irregular ovulatory cycle and metabolic derangement , including glucose intolerance and hyperinsulinaemia. Hyperandrogenism is a clinical hallmark of PCOS. Hypersecretion of androgen by the stromal theca cell of polycystic ovary is cardinal clinical manifestation. Though the exact cause of PCOS is not known , the syndrome can result from disturbance in the hypothalamo pituitary ovarian axis and hyperinsulinaemia. Several definitions have been produced to describe the disease. European society of human reproduction and embryology and the American society for reproductive medicine in 2004 define PCOS as manifestation of two of the following three J Bangladesh Coll Phys Surg 2019; 37(2): 78-82

Ovarian steroid secretion capacity starts to decline as early as around the age of 30 yr. Whether an age-related decrease in androgen secretion, as in normal women, also occurs in women with polycystic ovary syndrome (PCOS) and whether the enhanced androgen production in PCOS remains throughout the fertile period of life are not known. The aim of this study was to determine the age-related serum basal and gonadotropin-stimulated androgen levels in women with PCOS and to compare the results with those obtained from our previous study in healthy women with normal ovaries. Human chorionic gonadotropin (hCG) stimulation tests were carried out among 42 women with PCOS (age, 16–44 yr; body mass index, 31.02 ± 1.1 kg/m2). An im injection of 5000 IU hCG was given 2–4 d after spontaneous or progestin-induced menstrual bleeding, and blood samples for LH, FSH, inhibin B, 17-hydroxyprogesterone, androstenedione (A), testosterone (T), and estradiol assays were collected at 0, 24, 48, and 96 h. In women with PCOS, basal serum T and A levels were about 50% higher than in healthy women. The responses of A and T to hCG [area under the curve (AUC), 96 h)] were significantly higher in women with PCOS than in normal women [A, 1183.6 ± 60 (±se) vs. 814.4 ± 39 (P ≤ 0.001); T, 192.9 ± 12 vs. 117.4 ± 6; P ≤ 0.001]. In PCOS women, the hCG-stimulated A levels correlated negatively with age (AUC of A: r = −0.044; P = 0.004), and a similar trend was also observed in AUC T levels (AUC of T: r = −0.125, P = 0.425). Despite the higher androgen secretion capacity in PCOS, the basal and hCG-stimulated serum estradiol levels were similar to those observed in normal women. LH correlated positively with age, but basal FSH and inhibin B levels remained unchanged. In conclusion, in PCOS basal serum levels of androgens and ovarian androgen secretion capacity are markedly increased and remain high throughout the reproductive years, although the decreasing ovarian capacity to release androgens in response to hCG stimulation seen in healthy women also occurs in PCOS.

Developmental origins of adult disease (DoHAD) refers to critical gestational ages during human fetal development and beyond when the endocrine metabolic status of the mother can permanently program the physiology and/or morphology of the fetus, modifying its susceptibility to disease after birth. The aim of this review is to address how DoHAD plays an important role in the phenotypic expression of polycystic ovary syndrome (PCOS), the most common endocrinopathy of women characterized by hyperandrogenism, oligo-anovulation and polycystic ovarian morphology. Clinical studies of PCOS women are integrated with findings from relevant animal models to show how intergenerational transmission of these central components of PCOS are programmed through an altered maternal endocrine–metabolic environment that adversely affects the female fetus and long-term offspring health. Prenatal testosterone treatment in monkeys and sheep have been particularly crucial in our understanding of developmental programming of PCOS because organ system differentiation in these species, as in humans, occurs during fetal life. These animal models, along with altricial rodents, produce permanent PCOS-like phenotypes variably characterized by LH hypersecretion from reduced steroid-negative feedback, hyperandrogenism, ovulatory dysfunction, increased adiposity, impaired glucose-insulin homeostasis and other metabolic abnormalities. The review concludes that DoHAD underlies the phenotypic expression of PCOS through an altered maternal endocrine–metabolic environment that can induce epigenetic modifications of fetal genetic susceptibility to PCOS after birth. It calls for improved maternal endocrine–metabolic health of PCOS women to lower their risks of pregnancy-related complications and to potentially reduce intergenerational susceptibility to PCOS and its metabolic derangements in offspring.

The importance of autophagy in polycystic ovary syndrome (PCOS)-related metabolic disorders is increasingly being recognized, but few studies have investigated the role of autophagy in PCOS. Here, transmission electron microscopy demonstrated that autophagy was enhanced in the ovarian tissue from both humans and rats with PCOS. Consistent with this, ovarian granulosa cells from PCOS rats showed increases in the autophagy marker protein light chain 3B (LC3B), whereas levels of the autophagy substrate SQSTM1/p62 were decreased. In addition, the ratio of LC3-II/LC3-I was markedly elevated in human PCOS ovarian tissue compared with normal ovarian tissue. Real-time PCR arrays indicated that 7 and 34 autophagy-related genes were down- and up-regulated in human PCOS , Signal-Net, and regression analysis suggested that there are a wide range of interactions among these 41 genes, and a potential network based on EGFR, ERBB2, FOXO1, MAPK1, NFKB1, IGF1, TP53 and MAPK9 may be responsible for autophagy activation in PCOS. Systematic functional analysis of 41 differential autophagy-related genes indicated that these genes are highly involved in specific cellular processes such as response to stress and stimulus, and are linked to four significant pathways, including the insulin, ERBB, mTOR signaling pathways and protein processing in the endoplasmic reticulum. This study provides evidence for a potential role of autophagy disorders in PCOS in which autophagy may be an important molecular event in the pathogenesis of PCOS.

AbstractPolycystic ovary syndrome (PCOS) is the most common endocrine disorder among women of reproductive age with reproductive, metabolic and endocrine implications. While the exact pathophysiological mechanisms of the syndrome are unknown, its heterogeneity suggests a multifactorial causal background. In the last two decades, numerous environmental chemicals, including Bisphenol-A (BPA) that is used in the synthesis of polycarbonate plastics, have been proposed as potential contributors to the aetiology of PCOS. This review provides a holistic overview of the available data regarding the possible relation of PCOS with BPA exposure. We have included a total number of 24 studies. Eleven human case-control and 13 animal studies provided data regarding this potential relation. Accumulating evidence suggests that a correlation between high levels of BPA and the presence of PCOS may exist. Contradicting results from human and animal studies, however, render it difficult to conclude on the exact role of BPA in the pathogenesis of PCOS. BPA may constitute a consequence of the syndrome rather than a cause, but further research is still needed to clarify this. Continued efforts to study the early origins of PCOS, using prospective-designed studies, are required to identify the exact effect of BPA on women with PCOS.

Thesis (MNutr)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: The role of fructose restriction in addition to dietary modifications for weight loss and lifestyle improvement, on fertility outcome and other markers of metabolic syndrome, in obese women with polycystic ovarian syndrome (PCOS) Introduction: At the time at which the current study was undertaken no data, as yet, existed on whether restriction of fructose, while treating obese patients with PCOS for weight loss, improves the clinical symptoms and metabolic/anthropometric profile so as to promote fertility. Objectives: To evaluate the baseline intake of fructose, as well as the effect of restricting fructose intake from fruit and soft beverages to less than 20 g daily, as well as to provide guidelines for weight loss on anthropometric measurements, for improving subjective clinical symptoms, and for promoting fertility outcome in obese patients with PCOS, who seek to become fertile. Methods: The study was conducted in the Tygerberg Hospital Infertility Clinic, as an experimental cohort. Patients with a body mass index (BMI) higher than 27, seeking fertility after diagnosis with PCOS, were referred for dietary consultation, and followed up 3 monthly over 1 year. At each visit anthropometric measurements and a detailed dietary history were taken and a questionnaire for clinical symptoms was completed. Results: Baselinely, 86 patients were included in the study. Averages for weight and BMI were 99.8 ± 24.3 kg and 39.2 ± 8.7kg/m2, respectively. Average baseline daily fructose intake was 167 ± 116.8g. At baseline, significant relationships were shown between fructose intake and burning feet (ρ=0.02) and frequent waking (ρ=0.02), with a trend towards nightly eating (ρ=0.07). The dropout rate after visit 1 was 50%, with a further dropout of 41% after visit 2. After 3 visits (n=18), fructose intake significantly reduced (ρ=0.018), with the significant relationships with clinical symptoms having disappeared by visit 2. After 3 visits (n=18), both weight and BMI decreased significantly (ρ=0.017) and (ρ=0.019), respectively. Fructose was tested as a covariate to BMI, with high significance (ρ=0.006) in said population group. Conclusion: Dietary intervention to reduce fructose intake proved significant for weight loss and BMI after 3 visits. Reduced fructose intake was associated with reduced clinical symptoms. With fructose being a significant covariate to BMI, it can be concluded that fructose overconsumption could possibly contribute to both clinical symptoms and elevated BMI in said study population.
AFRIKAANSE OPSOMMING: Die rol wat die beperking van fruktose speel bykomend tot dieetaanpassings en lewenstylverbetering vir gewigsverlies by oorgewig vroue met polisistiese ovariële sindroom (PCOS) in die uitkoms van fertiliteit en ander merkers van metaboliese sindroom. Inleiding: Met die aanvang van hierdie studie was daar is geen data beskikbaar oor die invloed van die beperking van fruktose in die dieet van oorgewig pasiënte met PCOS wat vir gewigsverlies behandel word nie. Dit was ook nie bekend of laasgenoemde pasiënte se kliniese simptome en metaboliese/antropometriese profiel sou verbeter met die beperking van fruktose sodat fertiliteit by hierdie pasiënte terselfdertyd ook bevorder word nie. Doelwitte: Die evaluering van die aanvanklike inname van fruktose, sowel as die beperking van fruktose afkomstig van eetbare vrugte en versoete drankies en sap tot ’n inname van minder as 20 g daagliks, tesame met riglyne vir gewigsverlies. Die uitkoms hiervan is bepaal deur antropometriese metings, die verbetering in subjektiewe kliniese simptome en die fertiliteituitkoms by oorgewig pasiënte wat hulp met fertiliteit verlang. Metodes: Die studie het as ’n eksperimentele kohort by die Infertiliteitskliniek by Tygerberg Hospitaal plaasgevind. Pasiënte wat na diagnose met PCOS fertiliteitsbehandeling verlang het en ’n BMI hoër as 27 gehad het , is vir dieetbehandeling verwys en driemaandeliks oor ’n tydperk van een jaar opgevolg. Tydens elke besoek is antropometriese metings en ’n omvattende dieetgeskiedenis geneem en ’n vraelys oor kliniese simptome ingevul. Resultate: Aanvanklik is 86 pasiënte by die studie ingesluit. Gemiddeldes vir gewig en BMI was 99.8 ± 24.3 kg en 39.2 ± 8.7 kg/m2 respektiewelik. Gemiddelde aanvanklike daaglikse inname van fruktose was 167 ± 116.8 g. Oorspronklik het betekenisvolle verhoudings tussen fruktose en die volgende bestaan: brandvoete (ρ=0.02) en veelvuldige episodes van nagtelike wakkerheid (ρ=0.02), met ’n neiging na nagtelike etery (ρ=0.07). Die uitvalsyfer na een besoek was 50% met ’n verdere uitvalsyfer van 41% na die tweede besoek. Na drie besoeke (n=18) het sowel die gewig as die BMI betekenisvolle afname getoon (ρ= 0.017) en (ρ=0.019), respektiewelik. Fruktose is as ’n belangrike kovariant vir BMI (ρ= 0.006) vir hierdie populasiegroep geïdentifiseer. Gevolgtrekking: Dieetintervensie vir die vermindering van die inname van fruktose was beduidend vir gewigsverlies en afname in BMI na drie besoeke. Verminderde fruktose-inname het gelei tot die vermindering van kliniese simptome. Met fruktose as beduidende kovariant vir BMI kan die gevolgtrekking gemaak word dat die oor-inname van fruktose by hierdie studiepopulasie waarskynlik tot sowel kliniese simptome as BMI bygedra het.

Folliculogenesis is a complex process that is central to the ovary’s primary function, the production of healthy oocytes. One of the essential ligand/receptor pairs that mediates folliculogenesis is kit ligand (KITL), a granulosa-derived cytokine growth factor, and its receptor, c-kit. Since their discovery two decades ago, the KITL/c-kit system has been extensively studied in animal models, in particular the mouse, in which it has been demonstrated to be crucial for normal folliculogenesis and fertility. To date, little investigation into KITL and c-kit has been performed in the adult human ovary. Previously, this laboratory showed abnormally increased KITL protein levels in human polycystic ovaries (PCO) compared to non-PCO, suggesting that KITL may contribute to several PCO phenotypes according to the range of actions KITL has been shown to have in animal folliculogenesis. Thus, this thesis aimed to characterise KITL and c-kit expression and localisation in the adult human ovary, including polycystic ovaries, and examined regulation of KITL gene expression by endocrine and intraovarian factors. To perform these studies, human ovarian tissues were obtained. These included granulosa cell subtypes cumulus and mural granulosa cells from women undergoing assisted reproductive technology treatment at infertility clinics, fresh ovarian cortex from the Royal Adelaide Hospital and archival paraffin-embedded human ovarian tissue from the Institute of Medical and Veterinary Sciences. The human granulosa tumour cell line, KGN, was also used as a model. KITL and c-kit isoforms were demonstrated to be present in the human ovary throughout follicle development. KITL-2 was shown to be expressed primarily by granulosa cells representing preantral follicles, while KITL-1 was the predominant isoform expressed in preovulatory granulosa cells, suggesting that KITL-2 may play a greater role during early follicle development which then diminishes in preovulatory follicles with increased KITL-1 levels. Both c-kit mRNA isoforms were found to be present in human ovarian cortex. Examination of c-kit localisation throughout follicle development by immunohistochemistry revealed that all follicular cell types in preantral and antral follicles expressed c-kit protein. This may suggest that KITL has an unknown autocrine function in granulosa cells unique to the human ovary, as animals models have previously demonstrated c-kit staining to be confined to the theca layer and the oocyte. c-kit staining patterns were found to be different in PCO compared to non-PCO preantral and antral follicles, suggesting a potential involvement for c-kit in PCO pathology. Collectively these results suggest, as demonstrated in various animal models, that the KITL/c-kit system is present in the human ovary and may have some involvement in the mediation of human folliculogenesis. Regulation of KITL gene expression was examined using KGN and cumulus cells. Based on previous studies, the candidate regulatory factors that were examined included androgen receptor (AR), endocrine factor follicle-stimulating hormone (FSH), theca-derived factor keratinocyte growth factor (KGF) and oocyte-secreted factors bone morphogenetic factor-15 (BMP-15) and growth differentiation factor-9 (GDF-9). Of these candidate factors, GDF-9 was found to directly decrease KITL gene expression in KGN cells and cumulus cells via ALK 4/5/7 receptors. There was also some evidence for a slight reversal of the GDF-9 effect on KITL expression by the addition of the potent androgen 5α-dihydrotestosterone (DHT). The results of these studies indicated KITL gene expression is regulated by GDF-9 in human granulosa cells and are consistent with observations of negative regulation of KITL expression in mouse granulosa cells. Evidence shown in this thesis suggests that the ratio of KITL isoforms in granulosa cells changes throughout human folliculogenesis. Follicular target cells for KITL signalling were found to include granulosa cells, theca cells and the oocyte, suggesting that the KITL/c-kit system may have potential roles throughout human folliculogenesis as demonstrated in animal models. Furthermore, this thesis has demonstrated that GDF-9 directly regulates KITL gene expression in human granulosa cells. From these results, this thesis proposes an in vivo model in which abnormally low levels of GDF-9, shown by a previous study to be characteristic of PCOS oocytes, results in increased KITL levels and this effect may be further exacerbated by the reversal of GDF-9 inhibition by excess androgen. This thesis has provided a greater understanding of the molecular mechanisms involved in human folliculogenesis which may be of use in future therapeutic strategies and diagnosis in assisted reproductive technology, and provide a basis for understanding human ovarian function and ovarian disease.
Thesis (Ph.D.) -- University of Adelaide, School of Paediatrics and Reproductive Health, 2013

Polycystic Ovary Syndrome (PCOS) is primarily thought of as a reproductive condition, although it has profound effects on metabolic health, with 38-80% of women with PCOS presenting with insulin resistance. This underlying insulin resistance occurs independently of obesity and has negative effects on other features of the condition. The identification of peripheral insulin resistance in PCOS occurred in 1989, and despite several advances in this area, the molecular mechanisms responsible for peripheral insulin resistance in women with PCOS remain unclear. In addition, interventional studies from women with PCOS have identified impaired responses to insulin-sensitizing therapies. A possible explanation for the underlying insulin resistance and poor response to insulin-sensitizing treatments may be the dysregulation of Transforming Growth Factor-beta (TGF-beta) signalling. The dysregulation of TGF-beta signalling is responsible for remodelling in the ovarian tissues and reproductive dysfunction. Due to the systemic action of TGF-beta signalling, it may be conceivable that these effects extend beyond the reproductive tissues to the peripheral tissues. This presents a possible mechanism that could contribute to the development of insulin resistance in women with PCOS. Understanding the underlying mechanisms of insulin resistance will allow for improvements in diagnosis and for targeted therapies to be developed, which are currently lacking for women with PCOS. The overall aim of this thesis was to determine if dysregulated TGF-beta signalling plays a role in skeletal muscle insulin resistance and can influence metabolic responses to exercise in women with PCOS. This was achieved through a combination of in vivo and in vitro studies focusing on skeletal muscle metabolism. Study 1 explored the role of TGF-beta ligands, TGF-beta 1 and Anti-müllerian hormone (AMH), on glucose uptake and insulin signalling in myotubes from women with PCOS and healthy controls. In line with previous studies, we showed that in vivo metabolic phenotype was not accurately retained in cultured myotubes from women with PCOS, suggesting that a combination of the in vivo environmental factors and intrinsic defects lead to the development of insulin resistance. TGF-beta 1 and AMH had distinct metabolic effects. TGF-beta 1 increased basal and insulin-stimulated glucose uptake, while AMH decreased glucose uptake and PI3K-p110 expression, which was accompanied by an increase in inhibitory IRS-1ser312 phosphorylation. Study 2 assessed the response of myotubes from women with PCOS and healthy controls to an in vitro model of contraction with and without TGF-beta 1 or AMH. It was found that myotubes from women with PCOS and healthy controls display minimal differences in exercise-induced signalling transduction. Myotubes from healthy women showed an increase in the phosphorylation of p38 MAPK and CREB, which appeared to be absent in the myotubes from women with PCOS. The TGF-beta ligands AMH and TGF-beta 1 do not appear to influence in vitro skeletal muscle exercise-like signalling responses. In Study 3, a cross-sectional approach was used to assess skeletal muscle TGF-beta and insulin signalling in women with PCOS compared to overweight and lean controls. Insulin sensitivity, as determined by euglycemic–hyperinsulinemic clamp, confirmed previous findings that women with PCOS have a significant reduction in insulin sensitivity compared to controls. This insulin resistance occurred in the absence of any identifiable defects in skeletal muscle insulin signalling and did not appear to be related to TGF-beta signalling. Women with PCOS had greater levels of basal phosphorylation of p38 MAPK, suggesting that excessive reactive oxygen species and/or inflammation may contribute to insulin resistance. In Study 4, overweight women with PCOS participated in a 12-week exercise training intervention. We aimed to determine if changes in insulin sensitivity following 12 weeks of moderate or high-intensity exercise training were related to aberrant TGF-beta signalling and collagen deposition in the skeletal muscle. Exercise training of high and moderate intensities resulted in improvements in insulin sensitivity and cardiorespiratory fitness, with the metabolic benefits being more noticeable following the high-intensity intervention. Improvements in insulin sensitivity occurred independently of changes in body composition, TGF-beta signalling and other clinical measures. Collectively, the results from these studies demonstrate the role of TGF-beta ligands and signalling dysregulation in skeletal muscle metabolism in vitro. However, these findings do not appear to translate in vivo where insulin sensitivity was not related to TGF-beta signalling in women with or without PCOS. There was no apparent evidence of dysregulation of TGF- beta signalling or insulin signalling in women with PCOS. Furthermore, improvements in insulin sensitivity following 12 weeks of high- or moderate-intensity exercise training occurred independently of changes in TGF-beta signalling.

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine issue described by unpredictable menses, hyperandrogenism, and polycystic ovaries (PCO). The commonness of PCOS changes relying upon which measures are utilized to conclude yet is just about as high as 15–20% when the European culture for human propagation and embryology/American culture for regenerative medication rules are utilized. Clinical signs incorporated grown-ups incorporate sort 1 diabetes, type 2 diabetes, and gestational diabetes. Insulin opposition influences half 70% of ladies with PCOS prompting a few comorbidities including metabolic condition, hypertension, dyslipidemia, glucose narrow-mindedness, and diabetes. Studies show that ladies with PCOS are bound to have expanded coronary corridor calcium scores and expanded carotid intima-media thickness. Psychological wellness problems including despondency, uneasiness, bipolar turmoil, and voraciously consuming food issues additionally happen all the more habitually in ladies with PCOS. Weight reduction works on feminine abnormalities, indications of androgen abundance, and barrenness the board of clinical appearances of PCOS incorporates oral contraceptives for feminine inconsistencies and hirsutism. Spironolactone and finasteride are utilized to treat indications of androgen overabundance.