睾酮对3T3-L1脂肪细胞胰岛素敏感性影响的机制研究

Effect of Testosterone on Insulin Sensitivity in 3T3-L1 Adipocytes

目的:探讨睾酮(T)对离体3T3-L1脂肪细胞胰岛素(Ins)信号通路影响的分子机制。方法:将3T3-L1前脂肪细胞诱导成熟,用10-5 mol/L T处理12 h,免疫印迹检测细胞Ins受体底物-1(IRS-1)的酪氨酸磷酸化水平及其总蛋白IRS-1、葡萄糖转运蛋白-4(GLUT-4)的表达,以及Ins刺激下膜蛋白GLUT-4的表达。加入核因子-κB(NF-κB)或ERK1/2的抑制剂预处理,再用免疫印迹检测细胞总蛋白中IRS-1的酪氨酸磷酸化水平及其总蛋白IRS-1、GLUT-4的表达,以及Ins刺激下膜蛋白GLUT-4的表达,[3H]-2-脱氧葡萄糖([3H]-2-DG)掺入法检测葡萄糖摄取率。结果:10-5 mol/L睾酮处理12 h与非T处理组相比,细胞总蛋白IRS-1及GLUT-4的表达均增多(P<0.05),但使Ins刺激下的IRS-1的酪氨酸磷酸化水平及膜蛋白GLUT-4的表达减少(P<0.05),加入ERK1/2或NF-κB的抑制剂后,IRS-1的酪氨酸磷酸化水平及膜蛋白GLUT-4的表达、葡萄糖摄取率能部分逆转。结论:ERK1/2/NF-κB信号通路是睾酮引起胰岛素抵抗(IR)的途径之一。

Objective： To explore the molecular mechanisms of effect of testosterone on insulin sensitivity in 3T3-L1 adipocytes in vitro. Methods： In basic state, matured 3T3-L1 adipocytes were treated with 10.5 mol/L testosterone for 12 h. In another experiment, adipocytes were manipulated following the same protocol except that cells were pretreated with PDTC （inhibitor of NF-κ3） or PD98059 （inhibitor of ERK1/2） for 2 h. The productions of insulin receptor substrate-1 （IRS-1）, Tyr941p IRS-1, GLUT-4 and the membrane proteins of GLUT-4 stimulated by insulin were analysed by Western blotting. The response of insulin-stimulated glucose uptake to pretreated by testosterone was determined by adding 2-deoxy [3H] glucose to differentiated 3T3-L1 adipocytes. Results： 3T3- L 1 adipocytes treated with 10.5 mol/L testosterone within 12 h obviously increased pruduction of IRS-1 and GLUT- 4 （P〈0.05）, while decreased the insulin-stimulated Tyr941p IRS-1 and membrane protein GLUT-4 production （P〈0.05）. While pretreated with PDTC or PD98059, the decreased production of insulinstimulated Tyr941p IRS-1 and membrane protein GLUT-4 could be partially reversed, and so did the response of insulin-stimulated glucose uptake. Conclusion： Testosterone could induce insunlin resistance （IR） via ERK1/2/NF-κB pathway.