乙醇对胰岛β细胞功能及胰岛素基因表达影响

Effect of ethanol on insulin mRNA expression and function of pancreatic islet β-cells

目的观察乙醇对原代培养的大鼠胰岛细胞及小鼠胰岛瘤细胞(NIT-1细胞)胰岛素分泌功能的影响并探讨其机制。方法体外培养的大鼠胰岛细胞及NIT-1细胞,不同剂量乙醇作用不同时间后,用放免法测定胰岛素分泌情况,RT-PCR方法检测胰岛素mRNA的表达。结果(1)乙醇对NIT-1细胞胰岛素分泌及胰岛素mRNA表达影响:作用6 h,胰岛素分泌增加,各剂量组(除400 mmol/L)胰岛素mRNA表达升高;作用12,24 h,胰岛素分泌降低,胰岛素mRNA表达均降低。(2)乙醇对原代培养的大鼠胰岛细胞的胰岛素分泌及胰岛素mRNA表达影响:作用12 h,低剂量组胰岛素分泌升高,胰岛素mRNA表达升高,高剂量组胰岛素分泌下降;胰岛素mRNA表达下降;随乙醇作用时间延长,胰岛素分泌先升高(6 h),然后下降(24 h),胰岛素mRNA表达短时间(6 h)上升,作用24 h表达下降。结论乙醇对胰岛β细胞胰岛素分泌及胰岛素mRNA表达的影响与作用时间、剂量有关,胰岛素mRNA表达水平的改变可能是乙醇影响胰岛β细胞胰岛素分泌的机制之一。

Objective To examine primary cultured rat pancreatic islet cells and NIT- 1 cells insulin secretion in response to a glucose challenge following exposure to different concentraions of ethanol, and to investigate the mechanism of the effect of ethanol on β- cell function. Methods After NIT - 1 cells and the primary cultured rat pancreatic islets cells were exposed to various concentraions of ethanol for certain time, the insulin secretion was measured by radioimmunoassay. Meanwhile, the levels of insulin mRNA expression were detected by RT - PCR method. Results （ 1 ） Effect of ethanol on glucose stimulated insulin secretion（GSIS）and insulin mRNA expression in NIT - 1 cells. At 6 h, ethanol increased GSIS. At 24 h and 12 h, ethanol decreased GSIS. At 6 h, ethanol（except for 400 mmol/L）upgraded insulin mRNA expression At 24 h, ethanol decreased insulin mRNA expression. （2）Effect of ethanol on GSIS and insulin mRNA expression in primary cultured rat pancreatic islet cells. Insulin release was increased at low concentration, but decreased markedly after exposed to high dosage of ethanol. Insulin mRNA expression was upgraded at low concentration, but began to decrease with the concentrations increasing. At 6 h, ethanol increased GSIS , but deccreased GSIS at 24 h. INS mRNA expression was upgraded at 6 h and began to decrease at 24 h. Conclusion Depending on the timing and concentrations, ethanol can exert both stimulatory and inhibitory effects on insulin secretion and insulin mRNA expression in pancreatic islet β- cells. Influence of ethanol on insulin mRNA expression may be involved in the effect of ethanol on insulin secretion.