MUSCLE GLUCOSE METABOLISM IN DIABETES AND EXERCISE

目前研究的主要发现是， 与糖尿病和肥胖症相关的是由于 葡萄糖转运蛋白在肌肉和无法易位 葡萄糖转运蛋白对胰岛素的反应。 行使 训练通过增加胰岛素抵抗基因的表达来克服胰岛素抵抗。 葡萄糖转运蛋白。 此外，急性运动 通过诱导葡萄糖移位增加肌肉葡萄糖转运 运输到细胞膜。 我们建议扩大这些重要的 观察以下研究。 肌肉葡萄糖转运蛋白（GLUT 4）蛋白和mRNA的增加， 运动训练和减少糖尿病动物。 我们的假设是 GLUT 4葡萄糖转运蛋白mRNA的变化是由于 通过第二信使cAMP途径介导的基因表达。 GLUT4 基因转录将通过核连续分析和mRNA 通过测量肌肉中GLUT 4 mRNA的下降来评估稳定性 用放线菌素D灌注。 如果转录受到调控， 将研究GLUT 4启动子的分析。 激活的代理 腺苷酸环化酶或抑制磷酸二酯酶将被用来调查 cAMP在GLUT 4基因表达调控中的作用。 肥胖Zucker大鼠的胰岛素抵抗已被证明是由于 不能将葡萄糖转运蛋白转运到细胞膜， 对胰岛素的反应。 我们的假设是细胞内有两个 葡萄糖转运蛋白的隔室，一个由胰岛素和 另一种是肌肉收缩（或缺氧），胰岛素抵抗是一种 葡萄糖转运蛋白被隔离在隔室中的结果， 它们只能通过肌肉收缩（或缺氧）来招募。 这 将通过测量葡萄糖转运和膜 GLUT 4转运蛋白在瘦的，久坐的， 肥胖和运动肥胖的动物。 这些大鼠的肌肉将被灌注 在基础状态下（含氧量正常，无胰岛素），存在胰岛素时 （10 ~（-7）M），处于缺氧状态。 膜组合技术 分离和免疫细胞定位将被用来研究这两个 一群传送者

The major findings of the current grant were that the insulin resistance associated with diabetes and obesity is due to a decrease in the amount of glucose transport protein in muscle and to an inability to translocate the glucose transporters to the cell membrane in response to insulin. Exercise training overcomes insulin resistance by increasing the expression of the glucose transporter protein in muscle. In addition, acute exercise increases muscle glucose transport by inducing the translocation of glucose transporters to the cell membrane. We propose to expand these important observations with the following studies. Muscle glucose transporter (GLUT4) protein and mRNA are increased by exercise training and decreased in diabetic animals. Our hypothesis is that the changes in GLUT4 glucose transporter mRNA are a result of altered gene expression mediated through the second messenger c-AMP pathway. GLUT4 gene transcription will be assayed by nuclear run-on analysis and mRNA stability will be assessed by measuring the decline of GLUT4 mRNA in muscle perfused with actinomycin D. If transcription is regulated, footprint analysis of the GLUT4 promoter will be investigated. Agents that activate adenylate cyclase or inhibit phosphodiesterase will be used to investigate the role of c-AMP in regulation of GLUT4 gene expression. The insulin resistance in obese Zucker rats has been shown to be due to an inability to translocate glucose transporters to the cell membrane in response to insulin. Our hypothesis is that there are two intracellular compartments of glucose transporters, one recruited by insulin and the other by muscle contraction (or hypoxia), and that insulin-resistance is a consequence of glucose transporters being sequestered in a compartment from which they can only be recruited by muscle contraction (or hypoxia). This hypothesis will be investigated by measuring glucose transport and membrane distribution of GLUT4 transporters in perfused muscle of lean, sedentary- obese, and exercised-obese animals. Muscles of these rats will be perfused in the basal state (normoxic, without insulin), in the presence of insulin (10-7M), and in the hypoxic state. The combined techniques of membrane isolation and immunocytolocalization will be used to investigate the two pools of transporters.