Glucose Meatbolism in the Human Ovary

描述（申请人提供）：GLUT 4是脂肪和肌肉中主要的胰岛素响应性葡萄糖转运蛋白，在调节葡萄糖代谢中发挥重要作用。虽然对性类固醇的调节不敏感，但GLUT 4通常在胰岛素抵抗状态下降低。GLUTx 1，也称为GLUT 8，是最近发现的葡萄糖转运蛋白，似乎是性类固醇调节的。它在人卵巢中表达，在人睾丸中被性类固醇抑制。 这些结果表明GLUT 8表达的性类固醇调节和GLUT 8可能参与提供生殖细胞中代谢过程和DNA合成所需的葡萄糖。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直接相关，也可能与生殖功能障碍直接相关。外周和卵巢GLUT 4和GLUT 8在多囊卵巢综合征（PCOS）妇女和正常周期妇女的相对表达仅部分特征。 GLUT 8和GLUT 4的改变可以为PCOS的病理生理学提供深入了解。为了阐明葡萄糖转运蛋白（例如GLUT 8和GLUT 4）在正常和PCOS卵巢中的作用，提出了以下特定目的。目的1将检查类固醇产生细胞系中葡萄糖转运和GLUT 8和GLUT 4表达/定位的调节，以检验GLUT 8而不是GLUT 4是卵巢内性类固醇调节的假设。将使用新型人卵巢卵泡膜样和颗粒样细胞系（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研究葡萄糖转运蛋白在正常人卵巢组织中的表达及细胞定位。目标3与目标2同时，将检验以下假设：PCOS女性的卵巢GLUT 8和GLUT 4表达相对于正常周期年龄和BMI匹配的对照组降低。目的2和3将通过一项前瞻性病例对照研究进行，研究对象为接受卵巢钻孔/楔形切除术以提高生育力的PCOS女性和一组接受选择性输卵管绝育术的正常周期性女性。将使用免疫组织化学、免疫印迹和RT-PCR/真实的时间PCR来确定GLUT 8和GLUT 4在不同组织中的表达和细胞定位。拟议的研究预计将提供对女性卵巢内葡萄糖转运调节的机制性见解，这是一个基本上尚未探索的领域。希望这些观察结果对了解PCOS的基本生殖生理学和生殖功能障碍的机制具有相关性。

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.