Malaisse W J, Hutton J C, Sener A, Levy J, Herchuelz A, Devis G, Somers G
J Membr Biol. 1978 Jan 18;38(3):193-208. doi: 10.1007/BF01871922.
The role of extracellular Ca2+ in the regulation of islet function is investigated. Decreasing extracellular Ca2+ concentrations cause a dose-related inhibition of glucose-induced insulin release. Whereas the efflux of 45Ca from perifused islets is transiently increased on exposure to Ca2+-deprived media, it is unaffected by a partial lowering of the extracellular Ca2+ concentration. Under the latter condition, therefore, the observed reduction in the size of the islets' exchangeable calcium pool(s) appears to be due to reduced Ca2+ entry. The proper effect of glucose on Ca handling by the islets is apparently not affected by a lowering in the extracellular Ca2+ concentration. Nevertheless, in islets exposed to glucose and incubated in Ca2+-deprived media, glucose uptake and oxidation and lactate output are decreased, whereas the islet ATP level is increased, as if extracellular Ca2+ shortage were to affect not only the cellular pool of Ca regulating insulin release, but also energy-consuming processes possibly located at the cell membrane.
研究了细胞外钙离子在胰岛功能调节中的作用。降低细胞外钙离子浓度会导致葡萄糖诱导的胰岛素释放呈剂量依赖性抑制。虽然在暴露于缺钙培养基时，来自灌流胰岛的45Ca外排会短暂增加，但它不受细胞外钙离子浓度部分降低的影响。因此，在后者情况下，观察到的胰岛可交换钙库大小的减少似乎是由于钙离子内流减少所致。葡萄糖对胰岛钙处理的正常作用显然不受细胞外钙离子浓度降低的影响。然而，在暴露于葡萄糖并在缺钙培养基中孵育的胰岛中，葡萄糖摄取、氧化和乳酸输出减少，而胰岛ATP水平升高，似乎细胞外钙短缺不仅会影响调节胰岛素释放的细胞钙库，还会影响可能位于细胞膜的能量消耗过程。
