Glucose Meatbolism in the Human Ovary

描述(申请人提供)：GLUT4是脂肪和肌肉中主要的胰岛素反应性葡萄糖转运体，在调节葡萄糖代谢方面发挥着重要作用。虽然对性激素的调节不敏感，但GLUT4在胰岛素抵抗状态下通常会降低。GLUTx1，也被称为GLUT8，是最近发现的一种葡萄糖转运蛋白，似乎受性类固醇调节。它在人的卵巢中表达，在人的睾丸中被性类固醇抑制。这些结果提示性激素调节GLUT8的表达，GLUT8可能参与生殖细胞代谢过程和DNA合成所需的葡萄糖的供应。葡萄糖转运活性可能是女性新陈代谢和生殖功能的重要决定因素。外周和卵巢葡萄糖转运蛋白的改变可能与胰岛素抵抗直接相关，也可能与生殖功能障碍有关。多囊卵巢综合征(PCOS)和正常周期妇女外周血和卵巢中GLUT4和GLUT8的相对表达仅有部分特征。GLUT8和GLUT4的变化有助于了解PCOS的病理生理机制。为了阐明葡萄糖转运蛋白(如GLUT8和GLUT4)在正常卵巢和PCOS卵巢中的作用，提出了以下具体目标。目的1研究GLUT8和GLUT4在类固醇产生细胞系中对葡萄糖转运和GLUT4表达/定位的调节，以验证GLUT8而不是GLUT4是卵巢内受性类固醇调节的假说。将使用新的人卵巢膜样细胞系和颗粒样细胞系(分别为HOTT和HGL-5细胞)。此外，还将评估罗沙格列酮(胰岛素增敏剂)在这些细胞中改善葡萄糖摄取和转运体表达/定位的能力。目的2研究葡萄糖转运蛋白在正常卵巢中的表达和细胞定位。与目标2同时进行的目标3将检验这样一种假设，即与正常周期、年龄和体重指数匹配的对照组相比，多囊卵巢综合征患者卵巢中GLUT8和GLUT4的表达减少。目标2和目标3将通过一项前瞻性病例对照研究进行，研究对象为多囊卵巢综合征患者，接受卵巢钻孔/楔形切除术以求生育，以及一组正常周期的妇女，接受选择性输卵管绝育术。采用免疫组织化学、免疫印迹和RT-PCR/Real-Time PCR方法检测GLUT8和GLUT4在不同组织中的表达和细胞定位。这项拟议的研究有望为女性卵巢内葡萄糖运输的调节提供机械性的见解，这一领域基本上还没有被探索过。这些观察结果有望对了解多囊卵巢综合征的基本生殖生理学和生殖功能障碍的机制有所帮助。

DESCRIPTION (provided by applicant): GLUT4 is the main insulin responsive glucose transporter in adipose and muscle which plays an important role in regulating glucose metabolism. While not sensitive to regulation by sex steroids, GLUT4 is commonly decreased in insulin resistant states. GLUTx1, also known as GLUT8, is a recently discovered glucose transporter that appears to be sex steroid regulated. It is expressed in human ovary and inhibited by sex steroids in human testis. These results suggest a sex steroid regulation of GLUT8 expression and a possible involvement of GLUT8 in the provision of glucose required for metabolic processes and DNA synthesis in germ cells. Glucose transport activity, could be an important determinant of metabolic as well as reproductive function in women. Alterations in peripheral as well as ovarian glucose transporters could be directly related to insulin resistance and perhaps to reproductive dysfunction. The relative expression of peripheral and ovarian GLUT4 and GLUT8 in women with Polycystic Ovarian Syndrome (PCOS) and normally cycling women has only partially been characterized. Alterations of GLUT8 and GLUT4 could provide insight into the pathophysiology of PCOS. To clarify the role of glucose transporters (e.g. GLUT8 and GLUT4) in normal and PCOS ovaries, the following Specific Aims are proposed. Aim 1 will examine the regulation of glucose transport and GLUT8 and GLUT4 expression/localization in a steroid-producing cell line to test the hypothesis that GLUT8, and not GLUT4, is sex steroid regulated within the ovary. Novel human ovarian theca-like and granulosa-like cell lines (HOTT and HGL-5 cells, respectively) will be used. Additionally, the ability of rosaglitazone (insulin sensitizer) to improve glucose uptake and transporter expression/localization in these cells will be assessed. Aim 2 will determine the expression and cellular localization of glucose transporters in normal human ovary. Aim 3, concurrent with Aim 2, will test the hypothesis that the ovarian expression of GLUT8 and GLUT4 is decreased in women with PCOS relative to normally cycling age- and BMI-matched controls. Aims 2 and 3 will be carried out by a prospective, case-control study of women with PCOS undergoing ovarian drilling/wedge resection for fertility and a group of normally cycling women undergoing elective tubal sterilization. Immunohistochemistry, immunoblots and RT-PCR/real time PCR will be used to determine the expression and cellular localization of GLUT8 and GLUT4 in different tissues. The proposed studies are expected to provide mechanistic insight into the regulation of glucose transport within the ovary in women, an area that has been essentially unexplored. These observations are hoped to have relevance for understanding of basic reproductive physiology and the mechanism of reproductive dysfunction in PCOS.