INSULIN ACTION IN POLYCYSTIC OVARY SYNDROME

胰岛素在多囊卵巢综合症中的作用

• 批准号: 2141413
• 负责人: Andrea E Dunaif
• 金额: $ 22.28万
• 依托单位: PENNSYLVANIA STATE UNIV HERSHEY MED CTR
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-07-01 至 1998-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2141413
• 关键词: alkaline phosphatase; denaturing gradient gel electrophoresis; diabetes mellitus genetics; family genetics; female; glucose metabolism; glucose tolerance test; hormone regulation /control mechanism; human subject; insulin; insulin receptor; insulin sensitivity /resistance; noninsulin dependent diabetes mellitus; obesity; phosphorylation; polycystic ovary syndrome; protein kinase; receptor binding; receptor coupling; women's health

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age. It is associated with profound insulin resistance resulting in a markedly increased risk for non-insulin dependent diabetes mellitus (NIDDM) at a strikingly early age (3rd-4th decades). The overall hypothesis of this research is that insulin resistance in PCOS is the result of several distinctive defects in insulin receptor-mediated signaling. Further, we propose that each defect has a unique genetic basis compared to defects producing insulin resistance associated with typical NIDDM, with obesity, or with the rare syndromes of extreme insulin resistance. We have found a novel abnormality of insulin- receptor signaling (increased insulin-independent insulin receptor serine phosphorylation and decreased insulin-stimulated insulin receptor tyrosine phosphorylation) in association with insulin resistance in approximately 50% of PCOS women. This defect is present in the major insulin target tissue, muscle, and persists in cultured cells suggesting a genetic abnormality. The Specific Aims of this proposal are, thus: 1) To determine the role of insulin receptor serine phosphorylation in the pathogenesis of insulin resistance in PCOS. We hypothesize that increased insulin- independent insulin receptor serine phosphorylation inhibits insulin- induced receptor-mediated signaling in PCOS. This will be investigated by examining the effects of dephosphorylation on the kinase activity of insulin receptors partially-purified from muscle and from fat, using serine specific (e.g. phosphatase type-2A) as well as nonspecific (e.g. alkaline phosphatase) phosphatases. 2) To determine whether there are post-insulin receptor signaling defects in PCOS. In PCOS there is a marked shift to the right in the insulin dose-response curve for glucose uptake in fat and in muscle as well as a decrease in adipocyte GLUT4 content. However, approximately 30% of such insulin resistant PCOS women have normal insulin receptor phosphorylation, and we hypothesize that these women have downstream signaling defects. Moreover, we hypothesize that 50% of PCOS women with defects in insulin receptor phosphorylation will also have decreased insulin-receptor mediated downstream signaling. This will be investigated by assessing insulin stimulation, in vivo and in intact adipocytes, of phosphatidylinositol 3-kinase (PtdIns 3-kinase) activity. Glucose uptake and GLUT4 content will also be determined. The ED50 insulin and Vmax for glucose use and for PtdIns 3-kinase activation will be examined. 3) To determine whether defects in insulin action in PCOS are genetic. If insulin resistance in PCOS is a genetic defect, first degree relatives should be affected. This will be investigated by determining total body and cellular insulin action in brothers of PCOS probands. We will screen for mutations in the insulin receptor and IRS-1 genes of PCOS women with denaturing gradient gel electrophoresis or single stranded conformation polymorphisms. Lean and obese PCOS women, brothers of PCOS women and age-, weight-, ethnicity- and sex-matched normal control subjects will participate in these studies.

多囊卵巢综合征（PCOS）是一种常见的内分泌疾病， 育龄妇女。它与深层胰岛素有关 抵抗导致非胰岛素风险显著增加 依赖性糖尿病（NIDDM）在惊人的早期（第3 - 4 十年）。这项研究的总体假设是， 多囊卵巢综合征的胰岛素抵抗是由胰岛素的几种独特缺陷引起的 受体介导的信号传导。 此外，我们建议每个缺陷都有一个 与产生胰岛素抵抗的缺陷相比， 与典型的NIDDM、肥胖或罕见的 严重的胰岛素抵抗 我们发现了一种新的胰岛素异常- 受体信号传导（增加非胰岛素依赖性胰岛素受体丝氨酸 磷酸化和减少胰岛素刺激的胰岛素受体酪氨酸 与胰岛素抵抗相关的蛋白质磷酸化 50%的PCOS女性这种缺陷存在于主要的胰岛素靶点 组织，肌肉，并坚持在培养的细胞，表明遗传 异常本建议的具体目标是：1）确定 胰岛素受体丝氨酸磷酸化在糖尿病发病机制中的作用 PCOS胰岛素抵抗我们假设增加的胰岛素- 独立的胰岛素受体丝氨酸磷酸化抑制胰岛素- 在PCOS中诱导受体介导的信号传导。 这将由以下人员进行调查 检测去磷酸化对激酶活性的影响， 从肌肉和脂肪中部分纯化的胰岛素受体， 丝氨酸特异性（例如磷酸酶-2A型）以及非特异性（例如， 碱性磷酸酶）磷酸酶。2)以确定是否存在 胰岛素后受体信号转导缺陷。在PCOS中， 葡萄糖摄取的胰岛素剂量-反应曲线右移 以及脂肪细胞GLUT 4含量降低。 然而，大约30%的胰岛素抵抗PCOS妇女 正常的胰岛素受体磷酸化，我们假设这些 女性有下游信号缺陷。此外，我们假设50% 胰岛素受体磷酸化缺陷的PCOS妇女也将 降低了胰岛素受体介导的下游信号传导。这将 通过评估胰岛素刺激，在体内和完整的 脂肪细胞，磷脂酰肌醇3-激酶（PtdIns 3-激酶）的活性。 还将测定葡萄糖摄取和GLUT 4含量。 的ed 50 胰岛素和葡萄糖使用和PtdIns 3-激酶激活Vmax将 接受检查。3)为了确定PCOS患者胰岛素作用的缺陷是否 遗传的如果PCOS的胰岛素抵抗是一种遗传缺陷， 亲属应该受到影响。这将通过确定 PCOS先证者兄弟的全身和细胞胰岛素作用。我们 将筛查PCOS患者胰岛素受体和IRS-1基因的突变， 变性梯度凝胶电泳或单链 构象多态性瘦和肥胖的PCOS妇女，PCOS的兄弟 女性和年龄、体重、种族和性别匹配的正常对照 受试者将参与这些研究。