C2C12 细胞胰岛素增敏的机制

目的:观察口服葡萄糖负荷对小鼠小肠组织网膜素基因表达的影响及网膜素对C2C12肌管细胞胰岛素敏感性的影响,并进一步探讨其机制。方法:半定量逆转录聚合酶链反应(RT-PCR)技术检测小鼠小肠组织网膜素mRNA的表达;葡萄糖转运实验观察网膜素对C2C12肌管细胞胰岛素敏感性的影响;Western blot检测Akt(Ser473)的磷酸化水平。结果:口服葡萄糖负荷30min后小鼠小肠组织网膜素基因表达显著减低(P<0.05),而60min后恢复至负荷前水平;葡萄糖转运实验发现:网膜素作用10min对C2C12肌管细胞基础葡萄糖转运无影响,但显著增加了胰岛素刺激的葡萄糖转运(P<0.05);Western Blot发现:网膜素和AICAR均显著增加了C2C12肌管细胞Ak(tSer473)的磷酸化水平(P<0.05)。结论:网膜素作为一种胃肠激素还受到葡萄糖负荷的调节,在C2C12肌管细胞,网膜素可通过增加Akt的磷酸化发挥胰岛素增敏作用。

Expression of Omentin in Intestine of Mice before and after Oral GlucoseUptake and Effects of Omentin on Insulin Sensitivityin C2C12 Myotubes

Objective: To analyze the mRNA expression of omentin mRNA level in intestine of mice before and after oral glucose uptake and to observe the effects of omentin on insulin sensitivity in C2C12 myotubes.Methods: Total RNA of intestine in mice before and after oral glucose uptake was isolated by TRIZOL method.Semi-quantitative RT-PCR was performed to quantitate the expressions of omentin.The uptake of 2-Deoxy——D-glucose was used to observe glucose transport.Western blot was performed to quantitate Akt(Ser473) phosphorylation.Results: The omentin mRNA level in intestine of mice 30min after oral glucose uptake was significantly decreased as compared with before glucose ingestion(P<0.05).60min after glucose intake,the omentin mRNA level recovered up to the level before uptake.Glucose transport test revealed that C2C12 myotubes treated with omentin for 10 minutes did not influenced basal glucose transport,but significantly increased insulin-stimulated glucose transport(P<0.05).Omentin and AICAR significently increased Akt(Ser473) phosphorylation of C2C12 myotubes in the presence of insulin(P<0.05).Conclusion: The expression of omentin in intestine of mice is regulated by glucose uptake.Omentin increases Akt phosphorylation in C2C12 myotubes in the presence of insulin,which may contribute to increase insulin sensitivity.