MECHANISMS OF HORMONAL CONTROL OF GLUCONEOGENESIS

糖异生的激素控制机制

• 批准号: 2133960
• 负责人: CLIFFORD Scott DEUTSCHMAN
• 金额: $ 9.34万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-04-01 至 1998-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2133960
• 关键词: G protein; adenylate cyclase; biological signal transduction; cyclic AMP; enzyme activity; fluorine; forskolin; genetic transcription; glucagon; gluconeogenesis; hormone receptor; hormone regulation /control mechanism; infection; laboratory rat; liver cells; magnesium; northern blottings; nuclear runoff assay; phosphoenolpyruvate carboxylase; prostaglandin E; protein biosynthesis; receptor coupling; western blottings

It has been shown that sepsis changes the ability of certain hormones, such as insulin and glucagon, to modify gluconeogenesis. One particularly interesting aspect of this alteration is that sepsis impairs hormonal modulation of levels of the mRNA coding for phosphoenolpyruvate carboxykinase (PEPCK), the enzyme that catalyzes a rate limiting step in hepatic gluconeogenesis. The project outlined in this proposal centers on elucidation of the mechanisms by which glucagon-induced increases in the transcription of the PEPCK gene are altered by sepsis. One hypothesis is that sepsis causes a defect in the behavior of the signal transduction pathway which mediates the intracellular effects of glucagon. This pathway is known to involve several components; a membrane bound receptor, the guanine regulatory protein Gs, the enzyme adenylate cyclase, the intracellular second messenger cyclic adenosine monophosphate (cAMP) and (an) intracellular factor(s) which lead(s) to transcription of the PEPCK gene. We propose to investigate each of the first four components and the way in which they interact to determine if sepsis alters their behavior. This will be accomplished by a) measuring the activity of PEPCK, levels of PEPCK mRNA and rate of transcription of the PEPCK gene in livers isolated from septic or sham operated rats perfused with cAMP or forskolin (which stimulates adenylate clyclase), b) determining NaF-or PGE1-stimulated adenylate cyclase activity in membranes isolated from hepatocytes derived from septic or sham operated animals, c) determining levels of Gs by immunoblot analysis and d) comparing the number of hepatocyte glucagon receptors in septic and sham- operated animals.

已有研究表明，脓毒症会改变某些荷尔蒙的能力， 如胰岛素和胰高血糖素，以改变糖异生。一 这种改变特别有趣的一点是，败血症损害了 编码磷酸烯醇式丙酮酸的基因水平的激素调节 羧酸激酶(PEPCK)，催化限速步骤 肝脏糖异生。本建议书中概述的项目主要集中在 关于胰高血糖素诱导血管内皮细胞数量增加的机制的阐明 脓毒症会改变PEPCK基因的转录。一 假说是败血症导致信号的行为缺陷。 介导细胞内效应的转导途径 高血糖素。已知这一途径涉及几个组成部分；a 膜结合受体，鸟嘌呤调节蛋白Gs，酶 腺苷环化酶，细胞内第二信使环腺苷 一磷酸(CAMP)和细胞内因子(S)导致(S) PEPCK基因的转录。我们建议调查每一起 前四个组件及其交互方式，以确定 败血症会改变他们的行为。这将通过a)测量来实现 PEPCK活性、PEPCK信使核糖核酸水平及转录速率 脓毒症和假手术大鼠肝脏中PEPCK基因的表达 用cAMP或Forsklin(刺激腺苷环化酶)灌流， B)测定NaF或PGE1刺激的腺苷环化酶活性 从脓毒症或假手术的肝细胞分离的膜 动物，c)通过免疫印迹分析测定Gs水平和d) 脓毒症与假手术组肝细胞胰高血糖素受体的比较 动手术的动物。