血管紧张素Ⅱ与人离体胰岛功能研究

Angiotensin Ⅱ and the function of isolated human pancreatic islets

目的探讨分离纯化的人胰岛表面血管紧张素Ⅱ1型受体(AT1)的存在与否,了解血管紧张素Ⅱ对人胰岛分泌胰岛素功能的影响。方法对分离纯化后的胰岛进行AT1受体和胰岛素的免疫荧光双标法检测;使用不同剂量血管紧张素Ⅱ探讨其对人胰岛胰岛素释放反应的影响。结果免疫荧光双标记染色胰岛AT1受体和胰岛素均呈强阳性;血管紧张素Ⅱ对高糖刺激胰岛素分泌具有剂量依赖的抑制效应,用AT1受体拮抗剂预处理胰岛能拮抗这种抑制作用。结论分离纯化的人胰岛存在AT1受体,血管紧张素Ⅱ能够通过AT1受体直接抑制胰岛的胰岛素释放反应。

Objective To investigate the existence of pancreatic type 1 angiotensin Ⅱ receptor （AT1 receptor） and the effect of angiotensin Ⅱ on the function of insulin secretion in the isolated human pancreatic islets. Methods The localization of ATl-receptors and insulin in islets were investigated by immunofluorescent double staining. Various concentrations of angiotensin Ⅱ were applied for studying its influence on the glucosestimulated insulin secretion （GSIS） of islets. Results ATl-receptors and insulin were strong positivity stained by immunofluorescent double staining in isolated human pancreatic islets; Exposure of the isolated islets to angiotensin Ⅱ induced a dose-dependent inhibition of GSIS. This inhibitory action was fully blocked by pretreatment of the islets with ATl-receptor antagonist. Conclusion These results suggest that AT1 receptor exists in the isolated human pancreatic islets, and angiotensin Ⅱ inhibits GSIS of the islets directly through AT1 receptors.