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目的 探讨游离脂肪酸是否会影响胰岛细胞Leptin受体的基因和蛋白表达及酪氨酸磷酸化 ,进而导致胰岛素抵抗及葡萄糖代谢的异常。方法 分离、培养新生SD大鼠胰岛细胞 ,分别与软脂酸 (0 2 5mmol/L)或油酸(0 12 5mmol/L)孵育 12、2 4、36h ,提取蛋白后用Western印迹法检测Leptin受体(OB R)的蛋白水平 ,用RT PCR检测胰岛细胞内OB RRNA含量的变化 ,用免疫沉淀法检测OB R的酪氨酸磷酸化程度。结果 软脂酸和油酸孵育后大鼠胰岛细胞OB R的蛋白表达水平在孵育 2 4、36h后均下调 (P <0 0 5 ) ;Leptin受体的RNA水平和酪氨酸磷酸化程度在各个时间点均下调 (P <0 0 5 )。结论 游离脂肪酸可对OB R的基因和蛋白表达水平及磷酸化程度产生一定的抑制作用 ,这种抑制作用可能是游离脂肪酸导致胰岛素抵抗的因素之一
Objective To investigate whether free fatty acids affect gene and protein expression of Leptin receptor and tyrosine phosphorylation in pancreatic islets, leading to insulin resistance and abnormal glucose metabolism. Methods The islet cells of neonatal SD rats were isolated and cultured. The cells were incubated with palmitic acid (0 2 5 mmol / L) or oleic acid (0 12 5 mmol / L) for 12, 24 and 36 h, respectively. (OB R). The level of OB RRNA in islet cells was detected by RT PCR. The tyrosine phosphorylation of OB R was detected by immunoprecipitation. RESULTS: The protein levels of OB R in rat pancreatic islet cells after incubation with palmitate and oleic acid were both down-regulated at 24 and 36 h after incubation (P <0.05). The levels of Leptin receptor mRNA and tyrosine phosphorylation All time points were down (P <0 05). Conclusions Free fatty acids can inhibit the gene and protein expression and phosphorylation of OB R, which may be one of the factors leading to insulin resistance by free fatty acids