脂联素受体在胰岛细胞表达,脂联素促进胰岛素的分泌

Adiponectin receptors are expressed on islet cells and adiponectin stimulates insulin secretion

目的检测脂联素受体(AR)在大鼠胰岛细胞的表达和脂联素对体外胰岛细胞分泌胰岛素的影响.方法 RT-PCR和免疫细胞化学方法检测AR1、AR2的mRNA和蛋白表达;并在体外用脂联素(100 μg/L)和不同浓度葡萄糖(3.3,5.6,16.7 mmol/L)处理胰岛细胞,放免法测定上清液的胰岛素浓度.结果 RT-PCR扩增出胰岛AR1和AR2基因,并经直接和亚克隆测序证实;胰岛免疫细胞化学荧光染色AR1和AR2呈阳性;经脂联素处理后的胰岛细胞,在高糖(16.7 mmol/)培养6～24 h,其胰岛素分泌持续增加(均P＜0.05).结论胰岛细胞上存在AR1和AR2,以前者为主.在高糖情况下,一定浓度的脂联素可在体外促进胰岛细胞的胰岛素分泌和释放.

Objective To assay the expression of adiponectin receptor (AR) on rat islet cells and the effect of adiponectin on insulin secretion of islets in vitro. Methods The gene expression of AR1 or AR2 on islets was confirmed by both RT PCR and immunocytochemistry. Rat islets were isolated and incubated with adiponectin (100 μg/L) and graded various glucose concentrations (3.3, 5.6, 16.7 mmol/L) for 2, 6 and 24 h, respectively. The insulin levels in supernatant were measured by RIA.. Results AR1 and AR2 (esp. AR1) were expressed in rat islets testified by RT PCR andimmunocytochemistry.WhenincubatedinDMEM medium with 16.7 mmol/L glucose for 6 h and 24 h, insulin secretion of the islet cells undergoing adiponectin (100 μg/L) treatment was continuously increased and maintained at a higher level during 24 h (both P<0.05). Conclusion AR1 (predominant) and AR2 are expressed on islet cells. When isletes are incubated with high glucose concentration (16.7 mmol/L), adiponectin enhances insulin secretion of islets in vitro.