游离脂肪酸对大鼠胰岛细胞体外分泌功能的影响

目的探讨饱和脂肪酸软脂酸和单不饱和脂肪酸油酸对大鼠胰岛细胞体外分泌胰岛素功能的影响。方法体外分离大鼠胰岛细胞,分为:①浓度梯度组,将0.125、0.250、.5 mmol/L软脂酸(PA)和油酸(OA)分别与胰岛细胞共培养48 h;②时间梯度组,将0.25 mmol/L软脂酸、油酸及二者的混合物与胰岛细胞共培养24、487、2 h,进行葡萄糖刺激胰岛素释放试验,放射免疫法检测培养液中胰岛素浓度。结果①浓度梯度组,不同浓度PA和OA组葡萄糖刺激后胰岛素分泌水平均明显减少,浓度越高胰岛素分泌越少,高浓度时(0.5 mmol/L),高糖刺激下OA组胰岛素分泌高于PA组;②时间梯度组,PA、OA及混合组,葡萄糖刺激后胰岛素分泌水平均明显减少,随时间延长,胰岛素分泌逐渐减低;相同时间段,各组胰岛素分泌无差异(P>0.05)。结论PA和OA对大鼠胰岛细胞分泌功能均有一定的抑制作用,呈剂量依赖性,PA抑制程度呈时间依赖性;高浓度时PA抑制程度大于OA;OA对PA诱导的胰岛细胞分泌功能损伤无保护及协同效应。

Effects of free fatty acids on the insulin secreting function of rat pancreatic islets

Objective To study the effects of saturated free fatty acids palmitic acid(PA) and monounsaturated free fatty acids oleic acid(OA) on the insulin secreting function of rat pancreatic islets.Methods Isolating and culturing the rat pancreatic islets in vitro,① the concentration group exposed the islets to PA,OA at different concentrations(0.125,0.25,0.5mmol/L) for 48h;② the time group exposed the islets to 0.25mmol/L PA,OA and a kind of mixture of them(both concentrations are 0.25mmol/L) for 24h,48h,72h,then made a glucose-stimulated insulin secretion test respectively,examined insulin level in every group by radioimmunoassay after stimulated by low glucose and high glucose and compare them.Results ① The concentration group insulin level in every group of PA or OA after stimulated by low glucose and high glucose was reduced significantly,and the higher concentration,the lower insulin level.At high concentration(0.5mmol/L),insulin level of OA group after stimulated by high glucose is higher than that of PA group;② The time group insulin level in every group of PA,OA and the mixture group after stimulated by low glucose and high glucose was reduced significantly.With the prolong of duration,insulin secretion was reduced gradually.There wasn't significant difference in the insulin level of every group at the same duration.Conclusion Both PA and OA exert inhibition on the insulin secretion function of rat pancreatic islets,and the degree of impact indicats a concentration-dependant fashion.The effect made by PA indicats a time-dependant fashion.OA cann't protect islets from PA-induced toxicity and they don't have synergistic effects on impairing the secreting function of islets.