INTEGRATIVE APPROACH TO UNDERSTAND ETIOLOGY & CAUSES OF TYPE II DIABETES

了解病因的综合方法

• 批准号: 6119782
• 负责人: IAN R SWEET
• 金额: $ 0.76万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-12-16 至 1999-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6119782
• 关键词: Mammalia; bioengineering /biomedical engineering; bioimaging /biomedical imaging; biomedical resource; human tissue; model design /development; radiography; technology /technique

Glucokinase (GK) has been shown to play the role of the glucose sensor in the pancreatic b-cell, by virtue of its role as the rate controlling step in glycolysis. GK also has a very high control strength on glucose induced insulin secretion. The approach that led up to these important discoveries was quantitative and mathematical modeling of GK kinetics. Glucose must be metabolized before insulin secretion is stimulated, and the coupling factor between its metabolism and the ionic events which lead to the exocytosis of insulin containing granules is the energy state of the cell, [ATP]/[ADP]. Dukes [1994] and MacDonald [1990] have proposed that the major source of ATP production serving as a stimulus for insulin release is that generated by glycolytically-derived NADH, which is shuttled into the mitochondria and oxidized. This suggests that the rate of ATP production from the Krebs cycle is approximately constant, so that when a greater amount of pyruvate enters the Krebs cycle after a rise in glucose levels, this is counterbalanced by a diminution of the entry of acetyl CoA derived from fatty acids. Further, the factors governing the entry of pyruvate into the Krebs cycle (pyruvate dehydrogenase activity; PDH) and fatty acid oxidation, although important to the proper functioning of the cell, are not mechanisms by which the cell regulates the amount of insulin to be released. We propose to apply the quantitative approach taken in elucidating the relation between GK and glycolysis, to that of PDH and the rate of entry of pyruvate into the Krebs cycle. The experimental approach utilizes a mass spectrometer with a specialized inlet system that can monitor with a response time of 7 seconds the concentrations of dissolved O2, 12CO2, and 13CO2 in response to 13C labeled substrates. By using O2 consumption as a measure of ATP production, and production of 13CO2 in the presence of [1-13C]pyruvate as a measure of PDH, the basic hypothesis that ATP production from the Krebs c ycle is constant despite an increase in flux thrugh PDH can be tested. Both the measurements and their interpretation need to be quantitative to allow for rigorous conclusions to be made, so mathematical modeling analysis will be used for hypothesis testing, parameter estimation, flux estimations and control strength analysis. Understanding the regulatory mechanisms of the Krebs cycle in the functioning of the b-cell is prerequisite for understanding the pathology of both Type I and II diabetes mellitus.

葡萄糖激酶 (GK) 已被证明发挥葡萄糖的作用 胰腺 b 细胞中的传感器，凭借其作为速率的作用 糖酵解的控制步骤。 GK也有很高的控制力 对葡萄糖诱导的胰岛素分泌的强度。 导致的方法 这些重要的发现都是定量和数学的 GK 动力学建模。 葡萄糖必须在胰岛素之前代谢 分泌受到刺激，其之间的耦合因子 代谢和导致胞吐作用的离子事件 含有胰岛素的颗粒是细胞的能量状态， [ATP]/[ADP]。 Dukes [1994] 和 MacDonald [1990] 提出 ATP 产生的主要来源，作为胰岛素的刺激物 释放是由糖酵解衍生的 NADH 产生的，即 穿梭进入线粒体并被氧化。 这表明 克雷布斯循环的 ATP 生成率大致恒定， 这样当更多的丙酮酸进入克雷布斯循环后 葡萄糖水平的上升，这被葡萄糖水平的减少所抵消 来自脂肪酸的乙酰辅酶A的进入。 此外， 控制丙酮酸进入克雷布斯循环的因素（丙酮酸 脱氢酶活性； PDH）和脂肪酸氧化，尽管 对于细胞的正常功能很重要，不是通过以下机制 细胞调节胰岛素的释放量。 我们 建议采用定量方法来阐明 GK 和糖酵解、PDH 和糖酵解速率之间的关系 丙酮酸进入克雷布斯循环。 实验方法 利用带有专门入口系统的质谱仪，可以 监测响应时间为 7 秒 响应 13C 标记底物溶解 O2、12CO2 和 13CO2。 通过使用 O2 消耗量作为 ATP 产量的衡量标准，以及产量 13CO2 在 [1-13C] 丙酮酸存在下作为 PDH 的测量， 基本假设：克雷布斯循环产生的 ATP 是恒定的 尽管通过 PDH 的通量有所增加，但仍可进行测试。 两者都 测量及其解释需要定量，以允许 为了得出严格的结论，所以数学模型分析 将用于假设检验、参数估计、通量 估计和控制强度分析。 了解 克雷布斯循环的调节机制 b 细胞是了解 I 型和 I 型病理学的先决条件 和II型糖尿病。