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蛋白，在调节葡萄糖代谢中起重要作用。虽然GLUT4对性类固醇的调节不敏感，但在胰岛素抵抗状态下，GLUT4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。它在人卵巢中表达，在人睾丸中受性类固醇抑制。这些结果表明，性类固醇调节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提供。葡萄糖转运活性可能是女性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和生殖功能障碍直接相关。外周血和卵巢GLUT4和GLUT8在多囊卵巢综合征（PCOS）女性和正常经期女性中的相对表达仅得到部分表征。GLUT8和GLUT4的变化可以为PCOS的病理生理提供线索。为了阐明葡萄糖转运体（如GLUT8和GLUT4）在正常卵巢和多囊卵巢中的作用，我们提出了以下具体目标。目的1将研究葡萄糖转运和GLUT8和GLUT4在类固醇产生细胞系中的表达/定位的调节，以验证卵巢内GLUT8而不是GLUT4受性类固醇调节的假设。将使用新的人卵巢卵泡样和颗粒样细胞系（分别为HOTT和HGL-5细胞）。此外，将评估罗格列酮（胰岛素增敏剂）改善这些细胞中葡萄糖摄取和转运蛋白表达/定位的能力。目的2将确定葡萄糖转运体在正常人卵巢中的表达和细胞定位。目的3和目的2将验证PCOS女性卵巢GLUT8和GLUT4的表达相对于正常循环年龄和bmi匹配的对照组降低的假设。目的2和3将通过一项前瞻性的病例对照研究来实现，该研究对接受卵巢钻孔/楔形切除以获得生育能力的PCOS女性和一组接受选择性输卵管绝育的正常周期女性进行研究。利用免疫组织化学、免疫印迹和RT-PCR/real - time PCR检测GLUT8和GLUT4在不同组织中的表达和细胞定位。拟议的研究有望为女性卵巢内葡萄糖运输的调节提供机制上的见解，这是一个基本上尚未探索的领域。这些研究结果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具有重要意义。

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.