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细胞中信号通路(S)的代谢步骤 并在分子水平上为所选择的 人和动物的相关生理症状。该项目的重点是 糖酵解和胰岛细胞上的葡萄糖激酶型葡萄糖传感器 线粒体作为代谢偶联因子的生成者 与生物物理细胞膜事件有关的中间代谢。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MAN和BHEcdb的相关临床实体 大鼠是一种相关的II型糖尿病的动物模型，由原发性 线粒体DNA缺陷。 MODY-2和HI-GK中已知错义突变的重组GKS 患者将以酶动力学为特征。底物亲和力， S型，和酶的稳定性将是主要关注的焦点。孤立 BetaHC、BetaTC和AlphaTC细胞的线粒体将用 包括31P和13C核磁共振在内的新的动态测试，允许研究ATP 动力学和首选代谢途径。新陈代谢 将在这些相同细胞系的完整细胞中探索偶联，并与 隔离的小鼠或大鼠胰岛。一大批肿瘤β细胞或α细胞 将被嵌入琼脂糖内形成“假胰岛”，这将使 非侵入性呼吸测量技术的应用，13C-以及 31P-核磁共振，为燃料流动的精确平衡研究提供了机会 (包括ATP动力学)，这到目前为止是不可能的。新陈代谢 我们将对完整的胰岛的偶联进行生理、生化、 通过成像技术。新陈代谢的暂时性发育 BHEcdb大鼠将探索完整β细胞的功能损害 模型，以寻找报告的最早的功能性表现 三磷酸腺苷合成酶Fo组分突变。

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.