胰岛素分泌及调节的分子机制  

The Molecular Mechanisms of Insulin Secretion and Its Regulation

作　　者：吴政星[1] 娄雪林[1] 瞿安连[1] 周专[1] 徐涛[1] 

机构地区：[1]华中科技大学生命科学与技术学院,武汉430074

出　　处：《生物化学与生物物理进展》2002年第3期342-347,共6页Progress In Biochemistry and Biophysics

基　　金：国家自然科学基金资助项目 (3 0 0 0 0 0 62和 3 0 0 2 5 0 2 3 ) .~~

摘　　要：胰岛素是机体最重要的激素之一 ,它调节机体的血糖稳定、促进同化代谢、调节细胞的分裂分化和生长发育 .胰岛 β细胞的胰岛素分泌受到营养物质、神经递质和激素的精确调控 .它们的作用部位可分为改变胞内第二信使物质水平的近端调节步骤 (钙依赖性 ) ,和直接作用于胞吐分子构件的末端调节步骤 (钙非依赖性 ) .胰岛素的胞吐过程与神经递质的释放机制类似 .葡萄糖等营养物质主要通过升高胞内的ATP/ADP比率 ,导致ATP敏感钾通道关闭、细胞膜去极化、钙内流这一途径增加胰岛素的分泌 .神经递质和部分激素通过其G蛋白偶联受体 G蛋白系统的跨膜信号转换后 ,影响胞内IP3 、DAG、Ca2 + 等第二信使物质水平 ,主要通过PKA、PKC等蛋白激酶途径 ,调节胰岛素的分泌 .胞内单体G蛋白参与了对囊泡运输和胞吐过程的调控 ,G蛋白也可能直接作用于胞吐过程 。Insulin is one of the most important versatile hormone, and its functions include regulation of glycemia homeostasis, enhancement of anabolism, control of cell division and differentiation, modulation of cell growth and development. The molecular mechanisms of insulin release and its regulation can be considered as a paradigm of endocrine secretion. Insulin is stored in large dense core vesicles and released by exocytosis, a multistage process involving transport of vesicles to the membrane, their docking, priming and final fusion with the plasma membrane. SNARE proteins are molecular machinery of exocytosis. Pancreatic islet beta Celts integrate signals of nutrients and hormone/neurotransmitter to release proper quantity of insulin needed for various state. It is well established that glucose and other metabolizable nutrients depotarize the beta cells membrane and ensure Ca2+ influx through the voltage calcium channel by change of ATP/ADP ratio and other metabolic coupling factors. Hormones and neurotransmitters exert their regulation effects on insulin secretion through the signal transduction of heterotrimeric and monomeric G-protein. There are two regulatory steps on exocytosis, proximal regulatory step via the change of second messengers and distal one at the level of exocytosis machinery itself.

关 键 词：G蛋白 钙离子 胞吐过程 胰岛素 分泌 调节 分子机制 

分 类 号：Q455[生物学—生理学] Q578