METABOLISM OF ISLETS OF LANGERHANS AND HORMONE RELEASE

描述：拟议工作的目标是探索关键的 燃料刺激的β细胞中信号传导途径的代谢步骤 并在分子水平上对所选的 人类和动物的相关生理症状。 该项目的重点是 调控糖酵解葡萄糖激酶葡萄糖传感器 线粒体作为代谢偶联因子的产生者， 中间代谢与生物物理细胞膜事件。 MODY-2和 与葡萄糖激酶（HI-GK）或谷氨酸脱氢酶相关的高胰岛素血症 （HI-GDH）突变是人类的相关临床实体，BHEcdb 大鼠是原发性糖尿病引起的II型糖尿病的相关动物模型， 线粒体DNA缺陷。 具有MODY-2和HI-GK中定义的已知错义突变的重组GK 患者将通过酶动力学来表征。 底物亲和力， S形性和酶稳定性将是主要关注点。 分离 betaHC、betaTC和alphaTC细胞的线粒体将被表征为 新的动态测试，包括31 P-和13 C-NMR，允许ATP的研究 动力学和优选的代谢途径。 代谢 将在这些相同细胞系的完整细胞中探索偶联， 分离的小鼠或大鼠胰岛。 大批量的肿瘤β或α细胞 将嵌入琼脂糖中形成“假胰岛”， 应用非侵入性呼吸测量技术，13 C-以及 31 P-NMR，为燃料流的精确平衡研究提供了机会 （包括ATP动力学），这是迄今为止不可能的。 代谢 将对完整胰岛中的偶联进行生理学、生物化学， 和成像技术。 代谢和代谢的时间发展 将在BHEcdb大鼠中探索完整β细胞中的功能损伤 模型，以寻找报告的最早功能表现， ATP合成酶Fo组分的突变。

DESCRIPTION: The proposed work has the objective to explore critical metabolic steps of the signaling pathway(s) in fuel-stimulated beta-cells and to provide mechanistic explanations at the molecular level for selected relevant physiological syndromes in man and animals. The project focuses on the glucokinase glucose sensor governing glycolysis and on islet cell mitochondria as generators of metabolic coupling factors that link intermediary metabolism with biophysical cell membrane events. MODY-2 and hyperinsulinemias linked to glucokinase (HI-GK) or glutamate dehydrogenase (HI-GDH) mutations are the relevant clinical entities in man and the BHEcdb rat is a pertinent animals model of type II diabetes caused by a primary defect of mitochondrial DNA. Recombinant GKs with known missense mutations defined in MODY-2 and HI-GK patients will be characterized by enzyme kinetics. Substrate affinities, sigmoidicity, and enzyme stability will be the primary focus. Isolated mitochondria of betaHC, betaTC, and alphaTC cells will be characterized with novel dynamic tests including 31P- and 13C-NMR, allowing the study of ATP kinetics and of preferred metabolic pathways, respectively. Metabolic coupling will be explored in intact cells of these same cell lines and with isolated mouse or rat islets. Large batches of tumorous beta-or alpha-cells will be embedded in agarose to form "pseudoislets" which will allow the application of non-invasive techniques of respirometry, and 13C- as well as 31P-NMR, providin an opportunity for exact balance studies of fuel flow (including ATP kinetics) that was heretofore not possible. Metabolic coupling in intact islets will be studied physiologically, biochemically, and by imaging techniques. The tempora development of metabolic and functional lesions in intact beta-cells will be explored in the BHEcdb rat model, to search for the earliest functional manifestations of the reported mutation in the Fo component of ATP synthase.