Arkhammar P, Nilsson T, Berggren P O
Department of Medical Cell Biology, University of Uppsala, Sweden.
Cell Calcium. 1989 Jan;10(1):17-27. doi: 10.1016/0143-4160(89)90040-7.
The effects of glucose on cytoplasmic free Ca2+ concentration, [Ca2+]i, and insulin release were investigated using pancreatic beta-cells isolated from obese hyperglycemic mice. Measurements of [Ca2+]i were performed in cell suspensions in a cuvette and in single cell-aggregates in a microscopic system, using fura 2 and quin 2. Insulin release was studied from indicator loaded cells in a column perifusion system. In the presence of 1.28 mM extracellular Ca2+, an increase in the glucose concentration from 0 to 20 mM had two major effects on [Ca2+]i. Initially there was a decrease, which was immediately followed by a pronounced increase. At reduced extracellular Ca2+, or when Ca2+ influx was blocked, glucose induced only a decrease in [Ca2+]i. With increasing intracellular concentrations of indicator, the effects of glucose on [Ca2+]i were markedly reduced. Changes in [Ca2+]i, similar effects being obtained in the cuvette and microfluorometric measurements, were paralleled by changes in insulin release. Insulin release from indicator loaded cells did not markedly differ from that of non-loaded controls, either with respect to rapidity or size in the response to the sugar. The addition of 20 mM glucose increased the efflux of fura 2, an effect that was not related to insulin release. Permeabilization of indicator loaded cells demonstrated a substantial amount of fura 2 bound intracellularly. Although the effects of glucose on [Ca2+]i seemed to be similar in fura 2 and quin 2 loaded cells, the demonstrated leakage and possible intracellular binding should be considered before using fura 2 for measurements in pancreatic beta-cells.
利用从肥胖高血糖小鼠分离出的胰腺β细胞，研究了葡萄糖对细胞质游离钙离子浓度（[Ca2+]i）和胰岛素释放的影响。使用fura 2和quin 2，在比色皿中的细胞悬液以及显微镜系统中的单细胞聚集体中进行[Ca2+]i的测量。在柱式灌流系统中，从加载指示剂的细胞研究胰岛素释放。在存在1.28 mM细胞外钙离子的情况下，葡萄糖浓度从0增加到20 mM对[Ca2+]i有两个主要影响。最初有一个下降，随后立即有一个明显的增加。在细胞外钙离子减少或钙离子内流被阻断时，葡萄糖仅诱导[Ca2+]i下降。随着细胞内指示剂浓度的增加，葡萄糖对[Ca2+]i的影响明显降低。[Ca2+]i的变化，在比色皿和显微荧光测量中获得类似结果，与胰岛素释放的变化平行。加载指示剂细胞释放的胰岛素，在对糖的反应速度或大小方面，与未加载的对照细胞没有明显差异。添加20 mM葡萄糖增加了fura 2的外流，这一效应与胰岛素释放无关。加载指示剂细胞的通透化表明细胞内结合了大量fura 2。尽管在加载fura 2和quin 2的细胞中葡萄糖对[Ca2+]i的影响似乎相似，但在使用fura 2测量胰腺β细胞之前，应考虑已证明的泄漏和可能的细胞内结合情况。
