FACTORS THAT MODIFY INSULIN ACTION

改变胰岛素作用的因素

• 批准号: 2133636
• 负责人: MARIA G BUSE
• 金额: $ 19.31万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 1978
• 资助国家: 美国
• 起止时间: 1978-05-01 至 1997-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2133636
• 关键词: Golgi apparatus; SDS polyacrylamide gel electrophoresis; carbohydrate biosynthesis; drug related diabetes mellitus; endoplasmic reticulum; enzyme mechanism; glucose transport; glycosylation; hexosamines; hyperglycemia; insulin; insulin dependent diabetes mellitus; insulin sensitivity /resistance; intracellular transport; laboratory rat; posttranslational modifications; protein isoforms; protein transport; transport proteins; western blottings

Insulin resistance is a characteristic feature of Type II diabetes, of uncontrolled Type I diabetes, and is also associated with a number of heterogenous conditions. The major objective of this study is to elucidate biochemical mechanisms which may contribute to insulin resistance in insulinopenic (Type I) diabetes, using rats with streptozotin (STZ)- induced diabetes as a model. l.) Several lines of evidence suggest that processing (N-glycosylation) of the insulin receptor is altered in rats with severe STZ-diabetes, suggesting that processing of other proteins may also be affected. Possible post-translational modification of glucose transporters (GLUT) from liver, muscle and adipose tissue of STZ-diabetic and control rats will be examined by 2-D gel electrophoresis (2-D SDS- PAGE) followed by immunoblotting with site-specific antibodies; with or without antecedent glycosidase treatment. Since 2-D SDS-PAGE reveals several processing isoforms of specific GLUT, cell fractionation studies will test the hypothesis that certain processing isoforms of GLUT4 are preferentially translocated to the plasma membrane in response to insulin. N-linked glycosylation and Golgi processing of a model peptide 125-I-N- octanoyl-Asp-Thyr-Thr-N (OTP) will be studied in hepatocytes of control and diabetic rats, to assess a defect in ER or Golgi processing and/or vesicular transport associated with diabetes. 2.) Increased flux through the hexosamine synthetic pathway has been proposed as a mechanisms of glucose-induced, glucose transport insulin resistance. Products of this pathway.may alter the glycosylation/processing of glycoproteins. The rate limiting enzyme for glucose entry into this pathway is glutamine: fructose-6-P amido transferase (GFAT). The regulation of GFAT, products of the pathway and the biochemical mechanisms by which these products may cause insulin resistance will be studied in tissue culture systems and in isolated muscles. The methods developed in these studies will then be applied in vivo, to evaluate the possible role of this pathway in glucose- induced insulin resistance in muscle and adipose tissue of intact animals, i.e. control rats, controls infused with glucose and diabetic rats. In a pilot study, possible alterations in this pathway will be examined in a murine model of Type II diabetes.

胰岛素抵抗是II型糖尿病的特征， 不受控制的I型糖尿病，也与许多 异源条件。这项研究的主要目的是阐明 可能导致胰岛素抵抗的生化机制 胰岛素（I型）糖尿病，使用链蛋白酶（STZ）的大鼠 - 诱发糖尿病作为模型。 l。）几条证据表明 胰岛素受体的加工（N-糖基化）在大鼠中改变 使用严重的STZ糖尿病，表明其他蛋白质的加工可能 也受到影响。 可能的葡萄糖翻译后修饰 STZ-糖尿病的肝脏，肌肉和脂肪组织的转运蛋白（GLUT） 和对照大鼠将通过2-D凝胶电泳（2-D SDS-- 页面），然后使用特定于位点的抗体进行免疫印迹；与OR 没有先决的糖苷酶处理。 由于2-D SDS-PAGE揭示了 细胞分馏研究的几种特定Glut的加工同工型 将检验以下假设：GLUT4的某些加工同工型是 响应胰岛素响应于质膜优先易位。 N连接的糖基化和高尔基肽的加工125-I-N- 将在对照的肝细胞中研究octanoyl-asp-thyr-thr-th-n（OTP） 和糖尿病大鼠，以评估ER或Golgi加工的缺陷和/或 与糖尿病有关的囊泡转运。 2.）通过增加通量 已经提出了己糖胺合成途径作为一种机制 葡萄糖诱导的葡萄糖转运胰岛素抵抗。这个产品 途径可能改变糖蛋白的糖基化/加工。费率 限制葡萄糖进入该途径的酶是谷氨酰胺： 果糖-6-P amido转移酶（GFAT）。 GFAT的调节，产品 这些产品可以通过的途径和生化机制 导致胰岛素抵抗将在组织培养系统和 孤立的肌肉。 这些研究中开发的方法将是 在体内应用，以评估该途径在葡萄糖中的可能作用 在完整动物的肌肉和脂肪组织中诱导胰岛素抵抗， 即控制大鼠，控制葡萄糖和糖尿病大鼠。 在 试点研究，将在此途径中检查该途径的可能改变 II型糖尿病的鼠模型。