MECHANISMS OF HORMONAL CONTROL OF GLUCONEOGENESIS IN SEP

已经表明败血症改变了某些激素的能力， 例如胰岛素和胰高血糖素，以改变胰岛素生成。 一 这种改变特别有趣的方面是脓毒症损害了 编码磷酸烯醇丙酮酸的mRNA水平的激素调节 羧激酶（PEPCK），催化细胞增殖的限速步骤的酶， 肝再生 该提案中概述的项目集中在 阐明胰高血糖素诱导的 PEPCK基因的转录被脓毒症改变。 一 一种假说是脓毒症导致信号行为的缺陷 转导途径，介导细胞内的影响， 胰高血糖素 已知该途径涉及几种组分： 膜结合受体，鸟嘌呤调节蛋白Gs，酶 腺苷酸环化酶，细胞内第二信使环腺苷 一磷酸（cAMP）和（一种）细胞内因子，导致 PEPCK基因的转录。 我们建议调查每一个 前四个组成部分以及它们相互作用的方式，以确定 败血症会改变他们的行为 这将通过a）测量 PEPCK活性、PEPCK mRNA水平和PEPCK基因转录速率均明显高于对照组， 脓毒症或假手术大鼠肝脏中PEPCK基因的表达 用cAMP或毛喉素（其刺激腺苷酸环化酶）灌注， B）测定NaF或PGE 1刺激的腺苷酸环化酶活性， 分离自脓毒症或假手术肝细胞的膜 动物，c）通过免疫印迹分析测定Gs的水平，和d） 比较脓毒症组和假手术组肝细胞胰高血糖素受体的数量， 操作的动物

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.