【作者】 宋玉峰； 吴坤； 罗智； 张丽晗； 卓梅琴； 谭肖英；

【Author】 Yu–Feng Song;Kun Wu;Zhi Luo;Li–Han Zhang;Mei–Qin Zhuo;Xiao-Ying Tan;Fishery College,Huazhong Agricultural University;

【机构】 华中农业大学水产学院；

【摘要】 为探讨瘦素对在体及离体条件黄颡鱼肝脏脂代谢的影响,实验测定了肝脏组织内脂肪含量、肝细胞内甘油三酯(TG)、脂代谢相关酶活性及m RNA表达水平(CPT I,6PGD,G6PD,FAS,ME和ICDH)及脂代谢相关转录因子m RNA表达水平(PPARα,PPARγ和SREBP-1)的变化,并采用JAK-STAT和IRS-PI3K通路抑制剂来初步探讨其通过的代谢通路。结果显示:腹腔注射瘦素可降低黄颡鱼肝脏内脂肪含量及脂类合成相关酶(6PGD,G6PD,ME,ICDH和FAS)的活性,而上调了CPT I的活性。在m RNA水平上,脂肪代谢相关酶及关键转录因子(PPARα,PPARγ和SREBP-1)也有所变化。细胞水平上,瘦素孵育显著降低细胞内TG含量及G6PD和PPARγ的m RNA表达水平,而上调了PPARα,CPT I和SREBP-1的m RNA的表达水平。此外,JAK-STAT和IRS-PI3K通路抑制剂抑制了瘦素所引起的变化。研究表明:瘦素可通过JAK-STAT和IRS-PI3K代谢通路来降低肝脏脂肪合成速率,升高脂肪分解速率,从而有效降低脂肪含量。本实验首次在酶活性水平与m RNA水平上,结合在体及离体探讨瘦素对脂代谢的的影响,为我们了解瘦素在脂代谢中所起的作用提供了帮助。更多还原

【Abstract】 The present study was conducted to investigate the effects and mechanism of leptin influencing lipid metabolism in yellow catfish Pelteobagrus fulvidraco. Hepatic lipid and intracellular triglceride(TG) content, the activities and/or expression level of several enzymes(CPT I, 6PGD, G6 PD, FAS, ME and ICDH) as well as the m RNA expression of transcription factors(PPARα, PPARγ and SREBP-1) involved in lipid metabolism were determined. Intraperitoneal injection of recombinant human leptin significantly reduced hepatic lipid content, activities of lipogenic enzymes as well as m RNA levels of 6PGD, G6 PD, FAS, PPARγ and SREBP-1 genes, but up-regulated activity and m RNA level of CPT I and PPARα. Using primary hepatocytes, rt-h LEP incubation also reduced TG content, m RNA levels of G6 PD and PPARγ genes, but enhanced m RNA levels of PPARα, CPT I and SREBP-1. Leptin-induced effects could partially be reversed by specific inhibitors AG490 and wortmanin, suggesting JAK-STAT and IRS-PI3 K signaling pathways were involved in the process of leptin-induced lipid metabolism.更多还原