Herchuelz A, Malaisse W J
Am J Physiol. 1980 Feb;238(2):E87-95. doi: 10.1152/ajpendo.1980.238.2.E87.
At normal extracellular 40Ca concentration (1.0--1.5 mM), D-glucose initially reduces and subsequently increases 45Ca efflux from prelabeled rat pancreatic islets, whether in the absence or presence of 20 mM Ca-EGTA. Thus, the initial fall cannot be attributed to a reuptake of effluent 45Ca. Both the fall and rise in effluent 45Ca represent sustained and rapidly reversible phenomena partially masked by one another. The dose-action relationship for the initial fall in 45Ca efflux (Km = 4.2 mM) differs vastly from that characterizing the secondary rise in 45Ca efflux (Km = 9.1 mM). Mannoheptulose, iodoacetate, and low temperature inhibit both the early fall and secondary rise in effluent radioactivity normally evoked by glucose. D-Glucose (8.3 mM) and D-glyceraldehyde (10 mM) exert comparable effects on 45Ca efflux. The initial fall and later increase in 45Ca efflux evoked by glucose, although dependent on the integrity of glucose metabolism, correspond to two distinct processes in the rapid regulation of Ca handling by the islet cells.
在细胞外40Ca正常浓度（1.0 - 1.5 mM）下，无论有无20 mM Ca - EGTA，D - 葡萄糖最初会降低随后增加预先标记的大鼠胰岛的45Ca流出。因此，最初的下降不能归因于流出的45Ca的再摄取。45Ca流出的下降和上升均代表持续且快速可逆的现象，二者部分相互掩盖。45Ca流出最初下降的剂量 - 作用关系（Km = 4.2 mM）与表征45Ca流出二次上升的剂量 - 作用关系（Km = 9.1 mM）有很大差异。甘露庚酮糖、碘乙酸和低温会抑制通常由葡萄糖引起的流出放射性的早期下降和二次上升。D - 葡萄糖（8.3 mM）和D - 甘油醛（10 mM）对45Ca流出具有类似的作用。葡萄糖引起的45Ca流出的最初下降和随后的增加，虽然依赖于葡萄糖代谢的完整性，但对应于胰岛细胞对钙处理快速调节中的两个不同过程。
