MUSCLE GLUCOSE METABOLISM IN DIABETES AND EXERCISE

糖尿病和运动中的肌肉葡萄糖代谢

• 批准号: 2140508
• 负责人: GERALD Lynis DOHM
• 金额: $ 12.18万
• 依托单位: EAST CAROLINA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-04-01 至 1997-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2140508
• 关键词: DNA footprinting; affinity labeling; autoradiography; binding proteins; cyclic AMP; diabetes mellitus; exercise; gel electrophoresis; gene expression; genetic promoter element; genetic transcription; glucose metabolism; glucose transport; hyperglycemia; hypoxia; insulin; insulin sensitivity /resistance; laboratory rabbit; laboratory rat; membrane transport proteins; messenger RNA; muscle contraction; muscle metabolism; nucleic acid probes; obesity; protein structure; radiotracer

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.

当前赠款的主要发现是胰岛素抵抗 与糖尿病和肥胖有关的是由于减少 肌肉中的葡萄糖转运蛋白，无法转移 葡萄糖转运蛋白响应胰岛素响应细胞膜。 锻炼 训练通过增加表达来克服胰岛素抵抗 肌肉中的葡萄糖转运蛋白。 此外，急性运动 通过诱导葡萄糖的易位来增加肌肉葡萄糖的转运 转运蛋白到细胞膜。 我们建议扩大这些重要的 通过以下研究进行观察。 肌肉葡萄糖转运蛋白（GLUT4）蛋白和mRNA通过 运动训练并减少糖尿病动物。 我们的假设是 GLUT4葡萄糖转运蛋白mRNA的变化是改变的结果 基因表达通过第二信使C-AMP途径介导。 glut4 基因转录将通过核跑分析和mRNA测定 稳定性将通过测量肌肉中GLUT4 mRNA的下降来评估稳定性 灌注肌动蛋白D。如果调节转录，则足迹 将研究GLUT4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用于研究 C-AMP在GLUT4基因表达调节中的作用。 肥胖扎克大鼠的胰岛素抵抗已被证明是由于 无法将葡萄糖转运蛋白转移到细胞膜中 对胰岛素的反应。 我们的假设是有两个细胞内 葡萄糖转运蛋白的车厢，一种由胰岛素和葡萄糖转运蛋白招募 其他肌肉收缩（或缺氧），胰岛素抵抗是一种 葡萄糖转运蛋白被隔离在一个隔间中的结果 它们只能通过肌肉收缩（或缺氧）招募。 这 假设将通过测量葡萄糖传输和膜来研究假设 GLUT4转运蛋白在灌注肌肉中的分布 肥胖和运动动物。 这些大鼠的肌肉将被灌注 在存在胰岛素的情况下，在基底状态（常氧，无胰岛素） （10-7m），在低氧状态下。 膜的组合技术 分离和免疫细胞化将用于研究两者 运输池。