TRANSGENIC MOUSE MODEL FOR FAMILIAL HYPERINSULINISM

这项提案的目的是了解β细胞如何结合 使用SUR 1敲除小鼠的代谢对膜活性的影响。 我们有 重建β细胞ATP敏感性K+通道，KATP，从 高亲和力磺酰脲受体（SUR 1）和沉默的成员， 小内向整流家族（KIR6.2）。 KATP是 用于治疗非胰岛素依赖型糖尿病的磺酰脲， NIDDM和用于治疗高胰岛素血症的K+通道开放剂（KCO）。 SUR 1是ATP结合盒超家族的成员， 跨膜结构域和两个核苷酸结合折叠（NBFs）。 KATP 通道在调节胰岛素分泌中起关键作用。 葡萄糖 代谢改变β细胞中的ATP/ADP比率，特别是MgADP 刺激KATP开放的水平，这使得β细胞处于静息状态， 膜电位SUR 1检测核苷酸水平的变化， 通过KATP的K+通量因此使β细胞膜去极化。 去极化激活电压门控Ca 2+通道;产生的Ca 2 + 瞬变触发胰岛素胞吐作用。 SUR 1突变， MgATP或影响其调节，导致持续性 婴儿高胰岛素血症性低血糖症（PHHI），一种常染色体隐性遗传病 一种新生儿疾病，尽管有严重的 低血糖 我们制作了SUR 1基因敲除小鼠，以表征 PHHI表型及胰岛素KATP通道功能的研究 分泌物 我们建议描述这些动物，特别是， 将测定葡萄糖、胰岛素、胰高血糖素和生长抑素的水平 为了确定纯合子SUR 1缺失小鼠是否是高胰岛素血症， 低血糖和表征杂合子动物。胰腺 将培养胰岛并用于电生理学检查。 KATP的特征。 这些老鼠将为 持续性低血糖最常见原因的研究 新生儿，并将提供深入了解的生理和病理 胰岛素分泌 我们将通过表达 在大鼠胰岛素II启动子控制下的胰腺中的SUR 1 cDNA。 由此产生的动物将用于研究胰腺外功能 SUR/KIR6.2 ATP敏感性钾通道，特别是在 神经元

The objective of this proposal is to understand how beta-cells couple metabolism to membrane activity using SUR1 null mice. We have reconstituted the beta-cell ATP-sensitive K+ channel, KATP, from the high affinity sulfonylurea receptor (SUR1) and a silent member of the small inward rectifier family (KIR6.2). KATP is the target for the sulfonylureas used to treat non-insulin dependent diabetes mellitus, NIDDM, and for K+ channel openers (KCOs) used to treat hyperinsulinism. SUR1 is a member of the ATP-binding cassette superfamily with multiple transmembrane domains and two nucleotide binding folds (NBFs). KATP channels play a key role in regulating insulin secretion. Glucose metabolism alters the ATP/ADP ratio in beta-cells, particularly MgADP levels that stimulate openings of KATP, which set the beta-cell resting membrane potential. SUR1 senses changes in nucleotide levels and reduces K+ flux through KATP thus depolarizing the beta-cell membrane. Depolarization activates voltage-gated Ca2+ channels; the resulting Ca2+ transients trigger insulin exocytosis. Mutations in SUR1 that inactivate KATP, or affect its regulation by MgADP, cause persistent hyperinsulinemic hypoglycemia of infancy (PHHI), an autosomal recessive disease of newborns characterized by high insulin levels despite severe hypoglycemia. We have made SUR1 null mice in order to characterize the PHHI phenotype and study the functions of KATP channels in insulin secretion. We propose to characterize these animals, specifically, the levels of glucose, insulin, glucagon and somatostatin will be assayed to determine if homozygotic SUR1 null mice are hyperinsulinemic and hypoglycemic and to characterize heterozygotic animals. Pancreatic islets will be cultured and used for electrophysiological characterization of KATP. These mice will provide research material for the study of the most common cause of persistent hypoglycemia in newborns, and will provide insight into the physiology and pathology of insulin secretion. We will correct the pancreatic defect by expressing SUR1 cDNA in the pancreas under control of the rat insulin II promoter. The resulting animals will be used to study extra-pancreatic functions of the SUR/KIR6.2 ATP-sensitive potassium channels, particularly in neurons.