Insulin signaling in theca cells from polycystic ovaries

简介（申请人提供）：多囊卵巢综合征（Polycystic ovarian syndrome， PCOS）是育龄妇女最常见的生殖内分泌疾病。大约四分之三的无排卵性不孕症女性患有多囊卵巢综合征，因此约占三分之一的继发性闭经女性和约90%的少经女性。多囊卵巢综合征的其他后果包括多毛症、复发性早孕流产的发生率显著增加、50-61岁心肌梗死的风险估计增加11倍、年轻时患子宫内膜癌的风险增加。在患有多囊卵巢综合征的女性中，一个一致的发现是卵巢产生异常大量的雄激素。有充分的证据表明，雄激素升高干扰优势卵泡的选择，导致多囊卵巢综合征。重要的是，胰岛素抵抗和多囊卵巢综合征的雄激素过量之间存在关联。很明显，胰岛素可以刺激卵巢雄激素的产生，但一个矛盾存在：胰岛素是如何过度刺激胰岛素抵抗女性卵巢鞘雄激素的产生的？有两种假设可以解释这种看似矛盾的现象。胰岛素抵抗女性的卵巢卵泡膜细胞不具有胰岛素抵抗性，或者卵泡膜细胞中存在不同的胰岛素信号机制调节葡萄糖代谢和雄激素产生。本研究的目的是确定胰岛素抵抗女性卵巢鞘膜细胞是否具有胰岛素抵抗性，探讨胰岛素调节雄激素生物合成的细胞内信号机制，并确定多囊卵巢鞘膜细胞中介导胰岛素作用的关键分子的浓度和/或活性是否存在差异。为了实现这些目标，我们将测量骨骼肌和卵巢卵膜细胞葡萄糖摄取对胰岛素的敏感性，以确定胰岛素敏感和胰岛素抵抗的多囊卵巢综合征女性对胰岛素的相对敏感性。我们已经建立了一个人类卵泡膜细胞培养模型，我们可以检查胰岛素信号的分子细节。重要的是，体外培养细胞中雄激素产生增加和类固醇生成酶mRNA过表达持续存在。我们拟利用该模型系统地确定胰岛素刺激cyp17活性和mRNA表达的细胞内信号通路，并比较正常周期对照女性和PCOS女性之间信号分子的浓度和活性。这些研究的结果有望为治疗女性多囊卵巢综合征的新疗法提供特异性的分子靶点。

DESCRIPTION (provided by applicant): Polycystic ovary syndrome (PCOS) is the most common reproductive endocrine disease in women of reproductive age. Approximately three-quarters of women with anovulatory infertility have PCOS, thus accounting for approximately one-third of women with secondary amenorrhea and approximately 90% of women with oligomenorrhea. Other consequences of PCOS are hirsutism, markedly increased incidence of recurrent early pregnancy loss, an estimated 11-fold increased risk of myocardial infarction between the ages of 50-61 years, and an increased risk of endometrial cancer at a young age. A consistent finding in women with PCOS is that the ovaries produce abnormally high amounts of androgens. There is good evidence to conclude that elevated androgens interfere with selection of dominant follicles and cause PCOS. Importantly, there is an association between insulin resistance and the androgen excess of PCOS. It is clear that insulin can stimulate ovarian androgen production, but a paradox exists: how can insulin hyperstimulate ovarian thecal androgen production in an insulin resistant woman? One of two hypotheses could explain the seeming paradox. Either the ovarian theca cells are not insulin resistant in insulin resistant women or there are distinct insulin signaling mechanisms regulating glucose metabolism and androgen production in theca cells. The purpose of the proposed studies is to determine if ovarian theca cells are insulin resistant in insulin resistant women, to explore the intracellular signaling mechanisms by which insulin regulates androgen biosynthesis, and to determine if there are differences in the concentrations and/or activities of key molecules mediating insulin action in theca cell from polycystic ovaries. To accomplish these goals, we will measure the sensitivity of skeletal muscle and ovarian theca cell glucose uptake in response to insulin to determine the relative sensitivity of these tissues to insulin in insulin sensitive and insulin resistant women with and without PCOS. We have established a human theca cell culture model in which we can examine the molecular details of insulin signaling. Importantly, increased androgen production and steroidogenic enzyme mRNA over-expression persist in the cultured cells in vitro. We propose to use this model to systematically determine the intracellular signaling pathway for insulin stimulation of CYP 17 activities and mRNA expression and then to compare the concentrations and activities of the signaling molecules between regularly cycling control women and women with PCOS. The results of these studies are expected to yield specific molecular targets for novel therapies to treat women with PCOS.