FACTORS THAT MODIFY INSULIN ACTION

改变胰岛素作用的因素

• 批准号: 2015605
• 负责人: MARIA G BUSE
• 金额: $ 21.28万
• 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 1999-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2015605
• 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，并且还与许多 异质条件本研究的主要目的是阐明 可能导致胰岛素抵抗的生化机制 胰岛素缺乏（I型）糖尿病，使用大鼠与链脲佐菌素（STZ）- 糖尿病作为模型。 （图中为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 严重的STZ糖尿病患者，这表明其他蛋白质的加工可能 也受到影响。 葡萄糖可能的翻译后修饰 STZ-糖尿病患者肝脏、肌肉和脂肪组织的GLUT 和对照组大鼠将通过2-D凝胶电泳（2-D SDS-聚丙烯酰胺凝胶电泳）进行检查。 PAGE），然后用位点特异性抗体进行免疫印迹;用或 而不进行糖苷酶处理。 由于二维SDS-PAGE显示 特定GLUT的几种加工亚型，细胞分级研究 将检验GLUT 4的某些加工亚型是 在胰岛素的作用下优先转移到质膜上。 模型肽125-I-N-的N-连接糖基化和高尔基体加工 将在对照肝细胞中研究辛酰-Asp-Thyr-Thr-N（OTP） 和糖尿病大鼠，以评估ER或高尔基体加工缺陷和/或 与糖尿病有关的囊泡运输。 2.）的情况。增加通量通过 己糖胺合成途径被认为是 葡萄糖诱导的葡萄糖转运胰岛素抵抗。品的 可以改变糖蛋白的糖基化/加工。率 葡萄糖进入该途径的限制酶是谷氨酰胺： 果糖-6-P酰胺基转移酶（GFAT）。 GFAT的监管，产品 的途径和生化机制，这些产品可以 胰岛素抵抗的原因将在组织培养系统中进行研究， 孤立的肌肉 在这些研究中开发的方法将 应用于体内，以评估该途径在葡萄糖- 在完整动物的肌肉和脂肪组织中诱导胰岛素抵抗， 即对照组大鼠、葡萄糖灌注对照组和糖尿病大鼠。 中 初步研究，可能的改变，这一途径将在一个 II型糖尿病的鼠模型。