Wolf B A, Colca J R, Turk J, Florholmen J, McDaniel M L
Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110.
Am J Physiol. 1988 Feb;254(2 Pt 1):E121-36. doi: 10.1152/ajpendo.1988.254.2.E121.
Changes in intracellular Ca2+ concentrations have a major role in the regulation of insulin secretion by islet beta-cells. It has recently become apparent that the endoplasmic reticulum plays a prominent role in the regulation of intracellular Ca2+ concentrations under basal conditions and during insulin secretion. This review describes biochemical properties of the endoplasmic reticulum that contribute to intracellular Ca2+ homeostasis including 1) an ATP-dependent Ca2+ uptake pump associated with a Ca2+-ATPase located in the endoplasmic reticulum; 2) Ca2+ release from the endoplasmic reticulum induced by the second messengers inositol trisphosphate and arachidonic acid as well as the guanine nucleotide GTP; and 3) a Ca2+ sequestration mechanism localized to the endoplasmic reticulum that is regulated by glucose 6-phosphate and glucose-6-phosphatase. The hypothesis is developed that these biochemical mechanisms participate in the regulation of intracellular Ca2+ concentrations and represent central intracellular events involved in the first phase of glucose-induced insulin secretion.
细胞内钙离子浓度的变化在胰岛β细胞胰岛素分泌的调节中起主要作用。最近已明显看出，内质网在基础条件下以及胰岛素分泌期间细胞内钙离子浓度的调节中发挥着重要作用。本综述描述了有助于细胞内钙离子稳态的内质网的生化特性，包括：1）与内质网中一种钙ATP酶相关的依赖ATP的钙离子摄取泵；2）由第二信使三磷酸肌醇、花生四烯酸以及鸟嘌呤核苷酸GTP诱导的内质网钙离子释放；3）一种定位于内质网的钙离子螯合机制，其受6-磷酸葡萄糖和葡萄糖-6-磷酸酶调节。由此提出一个假说，即这些生化机制参与细胞内钙离子浓度的调节，并代表葡萄糖诱导胰岛素分泌第一阶段所涉及的核心细胞内事件。
