PCOS患者脂肪组织IRS-1、IRS-2蛋白表达及其酪氨酸磷酸化的研究

目的:研究多囊卵巢综合征(polycystic ovary syndrome,PCOS)患者脂肪组织胰岛素受体底物-1(insulin receptor substrate-1,IRS-1)及胰岛素受体底物-2(insulin recep-tor substrate-2,IRS-2)蛋白的表达及其酪氨酸磷酸化,探讨PCOS产生胰岛素抵抗(insulinresistance,IR)的分子机制。方法:用放射免疫法检测各实验组血清促黄体生成素(luteini-zing hormone,LH)、促卵泡激素(follicle stimulating hormone,FSH)、睾酮(testosterone,T)、血清空腹胰岛素(fasting insulin,FIN)的水平;用葡萄糖氧化酶法测定血浆空腹血糖(fast-ing plasma glucose,FPG);用HOMA(homeostasis model assessment,HOMA)模型计算胰岛素抵抗指数(HOMA-IR);用Western blot检测IRS-1及IRS-2蛋白的表达,应用免疫沉淀及增强化学发光法检测二者的酪氨酸磷酸化程度。结果:(1)PCOS IR组患者血清LH、LH/FSH、T、FIN及HOMA-IR均显著高于PCOS非IR组与对照组(均P(0.05);(2)PCOSIR组与PCOS非IR组及对照组相比,IRS-1蛋白表达量明显下降(P(0.05),IRS-2蛋白表达差异无统计学意义(P>0.05);(3)PCOS IR组IRS-1及IRS-2蛋白质酪氨酸磷酸化程度显著降低(均P(0.05)。结论:PCOS患者脂肪组织IRS-1蛋白表达下降,IRS-1及IRS-2蛋白质酪氨酸磷酸化程度降低,由此导致的受体后信号转导障碍可能是产生胰岛素抵抗的机制之一。

Tyrosine phosphorylation and protein expression of insulin receptor substrate-1 and 2 in the adipose tissue from patients with polycystic ovary syndrome

Objective:To investigate the tyrosine phosphorylation and protein expressions of insulin receptor substrate-1 and 2 in adipose tissue from patients with polycystic ovary syndrome,and explore molecular mechanisms of insulin resistance of PCOS.Methods:Serum luteinizing hormone(LH),follicle stimulating hormone(FSH),testosterone(T) and fasting insulin(FIN) were measured by chemiluminescence assay.Fasting plasma glucose(FPG) was measured by oxidase assay.The abundance of insulin receptor substrate-1 and 2 in adipose tissue was assessed by Western blot.The tyrosine phosphorylation of IRS-1 and IRS-2 was measured by immunoprecipitation and enhanced chemiluminescent immunoblotting technique.Results:(1) The levels of serum LH,LH/FSH,T,FIN and HOMA-IR in PCOS without insulin resistance were significantly higher than those of control group(all P<0.05);(2)The protein expression of IRS-1 in PCOS with insulin resistance was significantly lower than those in PCOS without insulin resistance and control group(P<0.05);(3)The tyrosine phosphorylation analysis of IRS-1 and IRS-2 were both significantly decreased in PCOS with insulin resistance compared to that of PCOS without insulin resistance and control groups(P〈0.05).Conclusion:Because of decreased IRS-1 protein expression and decreased tyrosine phosphorylation of IRS-1 and IRS-2 in the insulin signal transduction pathway may be one of the mechanism leading to insulin resistance.