Hafko Roman, Orecná Martina, Bacová Zuzana, Kolláriková Gabriela, Lacík Igor, Strbák Vladimír
Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia.
Cell Physiol Biochem. 2009;24(5-6):441-50. doi: 10.1159/000257482. Epub 2009 Nov 4.
Alcohol causes reactive hypoglycemia by attenuating the release of counter regulatory hormones, redistribution of pancreatic blood flow and direct stimulation of insulin secretion. Objective of this study was characterization of ethanol-induced insulin secretion. Signaling of ethanol- and glucose-induced insulin release from INS-1 and INS-1E cells was compared. Both cell lines responded similarly to all experimental interventions. In contrast to glucose, ethanol-induced insulin secretion was not hindered in calcium depleted medium or by addition of 10 microM BAPTA/AM (intracellular chelator). Inhibitor of protein kinase C Bisindolylmaleimide (3 microM) abolished glucose- but not ethanol-induced insulin secretion. Tetanus toxin (20 nM), inhibitor of SNARE proteins complex formation, blocked ethanol-induced insulin secretion. Both 5 mM N-ethylamaleimide and 10 microM ZnCl(2) (inhibitor of protein tyrosine phosphatases), which block disassembly of SNARE complexes and their further participation in exocytosis, increased basal insulin secretion. In contrast to glucose, already high insulin secretion was further increased after ethanol stimulation in either treatment.
Signaling of ethanol-induced insulin secretion from INS-1 and INS-1E cell lines bypasses calcium and PKC involving steps, is sensitive to tetanus toxin but resistant to N-ethymaleimide and ZnCl(2). An extra pool of secretory vesicles not available for glucose is exploited for exocytosis after ethanol stimulation.
酒精通过减弱反调节激素的释放、胰腺血流的重新分布以及直接刺激胰岛素分泌来导致反应性低血糖。本研究的目的是对乙醇诱导的胰岛素分泌进行表征。比较了乙醇和葡萄糖诱导INS-1和INS-1E细胞释放胰岛素的信号传导。两种细胞系对所有实验干预的反应相似。与葡萄糖不同，在缺钙培养基中或添加10微摩尔BAPTA/AM（细胞内螯合剂）时，乙醇诱导的胰岛素分泌不受阻碍。蛋白激酶C抑制剂双吲哚马来酰亚胺（3微摩尔）消除了葡萄糖诱导的胰岛素分泌，但未消除乙醇诱导的胰岛素分泌。破伤风毒素（20纳摩尔），一种SNARE蛋白复合物形成的抑制剂，阻断了乙醇诱导的胰岛素分泌。5毫摩尔N-乙基马来酰亚胺和10微摩尔氯化锌（蛋白酪氨酸磷酸酶抑制剂）都阻断了SNARE复合物的分解及其进一步参与胞吐作用，增加了基础胰岛素分泌。与葡萄糖不同，在任何一种处理中，乙醇刺激后已经很高的胰岛素分泌进一步增加。
INS-1和INS-1E细胞系中乙醇诱导的胰岛素分泌信号传导绕过了涉及钙和蛋白激酶C的步骤，对破伤风毒素敏感，但对N-乙基马来酰亚胺和氯化锌有抗性。乙醇刺激后，利用了一个葡萄糖不可用的额外分泌囊泡池进行胞吐作用。
