ROLE OF PLASMA MEMBRANE IN STIMULUS-SECRETION COUPLING

这项研究计划的长远目标是 确定葡萄糖细胞质膜的作用， 刺激-分泌偶联反应性胰岛素瘤 它控制钙流的机制。 具体而言，我们希望做到以下几点：1） 表征电压依赖性钙通道并研究其 影响细胞内钙离子浓度， 胰岛素释放; 2）研究β细胞的葡萄糖转运 研究葡萄糖和其他代谢物对细胞膜的影响 胰岛素促分泌素对Ca ~（2+）-ATP酶活性的影响， 4）研究钙离子对细胞膜钙离子流的影响， 胰岛素依赖型糖尿病患者的质膜抗体 钙通道，细胞间钙离子浓度， 胰岛素释放、葡萄糖转运和Ca 2 +-ATP酶活性。 到 完成这些目标，完整的β细胞或质膜 准备将使用。 在完整的β细胞中，胰岛素释放和 细胞质钙浓度的变化 促分泌素将在存在和不存在的情况下进行研究， 钙通道激动剂Bay K 8644和拮抗剂 尼群地平在灌流系统中的应用。 同时胰岛素 细胞内钙的释放和变化将在 在相同条件下的细胞悬浮液。 此外，急性 促分泌素对（3 H）- 尼群地平将在完整的胰岛素瘤细胞中进行研究。 钙 通道也将在质膜中表征 准备. 质膜制剂或膜囊泡将 也可用于研究葡萄糖和其他己糖对 Ca ~（2+）-Mg ~（2+）-ATP酶。 由于质膜一直是抗体的目标 在胰岛素依赖型糖尿病患者中发现，我们将使用 完整的细胞或质膜制备， 研究免疫球蛋白组分的作用， 糖尿病患者进行所有实验。 这些研究将使 重要的洞察力的功能质膜作为一个 胰岛素释放调节剂及其参与 糖尿病的发病机制。

The long-range objective of this research proposal is to determine the role of the plasma membrane of a glucose- responsive insulinoma in stimulus-secretion coupling by analyzing the mechanisms by which it controls calcium fluxes. Specifically, we wish to accomplish the following: 1) to characterize voltage-dependent calcium channels and study their influence on the intracellular calcium ion concentration and insulin release; 2) to study glucose transport by the beta-cell plasma membrane; 3) to study the effect of glucose and other insulin secretagogues on Ca2+-ATPase activity and transmembrane calcium fluxes; 4) to investigate the effect of plasma membrane antibodies from insulin-dependent diabetics on calcium channels, interacellular calcium ion concentration, insulin release, glucose transport and Ca2+-ATPase activity. To accomplish these goals, intact beta-cells or a plasma membrane preparation will be used. In intact beta-cells, insulin release and changes in cytosol calcium concentrations in response to secretagogues will be studied in the presence and absence of the calcium channel agonist Bay K 8644 and the antagonist nitrendipine in a perifusion system. Simultaneously insulin release and changes in intracellular calcium will be studied in cell suspensions under identical conditions. In addition, acute and chronic effects of secretagogues on the binding of (3H)- nitrendipine will be studied in intact insulinoma cells. Calcium channels will also be characterized in a plasma membrane preparation. The plasma membrane preparation or membrane vesicles will also be used to study the effects of glucose and other hexoses on the "calcium-pump, Ca2+-Mg2+-ATPase. Since the plasma membrane has been the target of antibodies found in patients with insulin dependent diabetes, we will use intact cells or the plasma membranes preparation from this tumor to study the effect of an immunoglobulin fraction from diabetics on all proposed experiments. These studies will give important insight on the function of the plasma membrane as a regulator of insulin release and on its involvement in the pathogenesis of diabetes.