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目的 通过观察抗高血糖药物二甲双胍对肝糖异生中的限速酶磷酸烯醇丙酮酸羧激酶 (PEPCK)基因表达的调节以及胰岛素信号转导抑制剂的影响 ,以探讨二甲双胍在肝细胞中作用的分子机制。方法 将小鼠肝癌细胞系 (H4IIE)细胞用不同浓度的二甲双胍温育 16小时 ,加入不同的调节因子如胰岛素、环磷酸腺苷 (cAMP)、地塞米松、胰岛素信号转导抑制剂等。PEPCK的mRNA水平通过Northern杂交分析。结果 治疗浓度 0 1mmol/L二甲双胍显著降低了基础PEPCK的mRNA水平 ,并通过与胰岛素的联合作用抑制了cAMP/地塞米松刺激的PEPCK的基因表达。胰岛素信号转导抑制剂如磷酯酰肌醇 3激酶 (PI3K)抑制剂渥蔓青霉素 (wortmannin)和有丝分裂原激活蛋白激酶 (MAPK)抑制剂UO12 6对二甲双胍的作用无显著影响 ,但wortmannin显著阻止了胰岛素对PEPCK基因表达的调节作用。结论 二甲双胍可通过独立的非胰岛素信号转导途径或是与胰岛素的联合作用抑制PEPCK的基因表达 ,表明二甲双胍降低肝糖异生的分子机制可能与PEPCK基因表达的抑制有关。
OBJECTIVE To investigate the effect of metformin on glycometabolism of phosphoenolpyruvate carboxykinase (PEPCK) in glycogen metabolism and the effect of insulin signaling inhibitors on hepatocytes Molecular mechanism. Methods Mouse liver cancer cell line (H4IIE) cells were incubated with different concentrations of metformin for 16 hours. Different regulatory factors such as insulin, cAMP, dexamethasone and insulin signal transduction inhibitors were added. The mRNA level of PEPCK is analyzed by Northern blotting. Results Treatment with 0.1 mmol / L metformin significantly reduced basal PEPCK mRNA levels and inhibited gene expression of cAMP / dexamethasone-stimulated PEPCK by a combination with insulin. Insulin signal transduction inhibitors such as phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin and mitogen-activated protein kinase (MAPK) inhibitor UO12 6 had no significant effect on metformin activity, but wortmannin significantly prevented Insulin modulates PEPCK gene expression. Conclusion Metformin can inhibit the expression of PEPCK gene through independent non-insulin signal transduction pathway or combined with insulin, indicating that the molecular mechanism of metformin in reducing glycogen may be related to the inhibition of PEPCK gene expression.