摘要
目的 探讨中枢nesfatin-1对肥胖大鼠肝胰岛素信号通路的影响。方法 成年雄性SD大鼠40只分为4组:(1)普通饮食人工脑脊液组(NCA);(2)普通饮食nesfatin-1组(NCN);(3)高脂饮食人工脑脊液组(HFA);(4)高脂饮食nesfatin-1组(HFN)。采用实时荧光定量PCR测定各组大鼠肝脏磷酸烯醇式丙酮酸羧激酶(PEPCK)和葡萄糖-6-磷酸酶(Glc-6-Pase)的mRNA表达,Western印迹检测PEPCK、Glc-6-Pase、InsR、IRS-1、Akt、AMPK、TORc2、mTOR的蛋白及其磷酸化表达水平,免疫组化测定nesfatin-1及人工脑脊液干预后下丘脑核团c-fos蛋白的表达。结果 高脂喂养抑制了大鼠肝脏InsR、IRS-1、Akt、AMPK和TORc2磷酸化水平。在普通及高脂饮食喂养条件下,中枢nesfatin-1干预均能显著降低大鼠肝脏PEPCK mRNA和蛋白表达(均P〈0.05),同时增加Akt及AMPK蛋白表达(P〈0.01或P〈0.05)。并且能促进大鼠肝脏InsR、IRS-1、TORc2和mTOR磷酸化(P〈0.01或P〈0.05)。此外,中枢nesfatin-1还增加了视上核、室旁核和弓状核的c-fos表达(均P〈0.01)。结论 中枢nesfatin-1通过激活InsR/IRS-1/AMPK/Akt/mTOR/TORc2信号通路改善肥胖大鼠肝胰岛素敏感性。
Objective To investigate the effects of central nesfatin-1 on insulin signaling pathway in liver of fat rats. Methods Forty adult male rats were divided into four groups:(1)Standard diet-artificial cerebrospinal fluid(NCA);(2)Standard diet-nesfatin-1(NCN);(3)High-fat diet-artificial cerebrospinal fluid(HFA);(4)High-fat diet-nesfatin-1(HFN). mRNA expression of PEPCK and Glc-6-Pase were assayed by real-time quantitative PCR, and protein expression of PEPCK, Glc-6-Pase, Akt, p-Akt, AMPK, p-AMPK, TORc2, p-TORc2, mTOR, and p-mTOR were determined by Western blot. The localization of c-Fos positive neurons was detected by means of immunohistochemical method in hypothalamus. Results High-fat diets inhibited phosphorylation of InsR, IRS-1, Akt, AMPK, and TORc2 in liver of rats. With regular chows diets and high-fat diets, central nesfatin-1 intervention significantly reduced the expressions of PEPCK mRNA and protein in liver of rats(P〈0.05), meanwhile increased the expressions of protein for AMPK and Akt(P〈0.01 or P〈0.05). Central nesfatin-1 intervention also promoted the phosphorylation of InsR, IRS-1, TORc2, mTOR in rats(P〈0.01 or P〈0.05). In addition, central nesfatin-1 also increased the expressions of the c-fos protein in paraventricular nucleus, supraoptic nucleus, and arcuate nucleus(P〈0.01). Conclusion Central nesfatin-1 improves insulin resistance through activating the phosphorylation of InsR/IRS/AMPK/Akt/mTOR /TORc2 signaling pathway in liver of rats.
出处
《中华内分泌代谢杂志》
CAS
CSCD
北大核心
2013年第2期157-161,共5页
Chinese Journal of Endocrinology and Metabolism
基金
国家自然科学基金项目(30771037,81070640,30871199和30971388)
教育部博士点基金(20105503110002)