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目的 研究二甲双胍抑制高浓度葡萄糖刺激的脂肪分解及其机制.方法 以SD大鼠附睾原代脂肪细胞为研究对象,分为对照A组、对照B组、实验A组和实验B组,每组3个平行管.对照A组予以5 mmol·L-葡萄糖,对照B组予以25 mmol·L-1葡萄糖,实验A组予以5 mmol·L-1葡萄糖+ 500 μmol·L-二甲双胍,实验B组予以25 mmol·L-1葡萄糖+ 500 μmol·L-二甲双胍.细胞孵育24h后,测定培养基中甘油释放量作为评价脂肪分解的指标,用酶化学法测定脂肪分解酶活性,用Western Blot法检测脂滴包被蛋白表达及其磷酸化水平、脂肪组织三酰甘油水解酶(ATGL)蛋白表达.结果 对照B组和实验B组的甘油释放量分别为(1.61±0.08)和(0.50±0.06).μmol·mL-1 packed cell volume,实验B组与对照B组比较明显降低,差异有统计学意义(P ＜0.001).这种抑制效应从孵育16 h开始明显并持续到24h.对照B组和实验B组的脂肪分解酶活性分别为(344.28±65.98)和(200.44±64.25)μmol glycerol·mg protein-1·h-1,2组比较,实验B组降低41.78％,差异有统计学意义(P＜0.05).与对照B组相比,实验B组脂滴包被蛋白磷酸化减少,差异有统计学意义(P＜0.01),但2组的ATGL蛋白水平与对照A组相比,差异均无统计学意义(均P＞0.05).结论 二甲双胍通过抑制脂滴包被蛋白磷酸化和脂肪分解酶活性,从而减少高浓度葡萄糖刺激的脂肪分解,这种效应可以减少糖尿病高血糖状态下游离脂肪酸从脂肪组织向血浆释放,进而减轻胰岛素抵抗.“,”Objective To investigate the inhibitory effect of metformin on high glucose-induced lipolysis and further elucidate the underlying mechanisms,for better understanding of metformin.Methods Adipocytes were isolated from epididymal fat pads of Sprague-Dawley rats.After isolation and digestion,packed adipocytes were divided into four groups according to the glucose and metformin in the media,control A group containing 5 mmol · L-1 glucose,control B group containing 25 mmol · L-1 glucose,test A group containing 500 μmol · L-1 metformin with 5 mmol · L-1 glucose and test B group containing 25 mmol · L-1 glucose with 500 μmol · L-1 metformin or at the concentrations as planned.After incubation,glycerol accumulated or released into the media in 30 minutes was determined by the use of a colorimetric assay and served as an index of lipolysis.The expressions of phosphorylated and total perilipin as well as adipose triglyceride lipase (ATGL) were examined by Western Blot.Adipose lipases activity was assayed by using an enzymatic method.Results The glycerol release in the control B and test B groups were (1.61 ± 0.08) and (0.50 ± 0.06) μmol · mL-1 packed cell volume,respectively,suggesting that metformin significantly inhibited the lipolytic action of high glucose (P ＜0.001).Such an inhibitory effect lasted from 16 h to 24 h after incubation.The adipose lipases activity in the control B and test B groups were (344.28 ± 65.98) and (200.44 ± 64.25)μmol glycerol · mg protein-1 · h-1,respectively,and thus metformin caused a 41.78％ (P ＜0.05) reduction of adipose lipases activity elevated by high glucose.Compared with control B group,metformin in test B group significantly attenuated the phosphorylation of perilipin induced by high glucose (P ＜ 0.01).However,the protein amount of total ATGL was not changed in control B group by high glucose or in test group (A and B) by metformin compared with that of control A group (all P ＞ 0.05).Conclusion Metformin inhibits high glucose-induced lipolysis through eliminating perilipin phosphorylation and suppressing lipolytic lipases activity.We suggest that such antilipolytic effect of metformin in hyperglycemia could be a molecular basis by which metformin reduces the release of free fatty acids from adipose tissue to bloodstream and thus ameliorates insulin resistance in diabetes.