胰岛素与低血流缺血刺激犬心肌GLUT4基因表达呈相加作用

目的：观察胰岛素与低血糖缺血刺激心肌葡萄糖转运子4（GLUT4）基因是否呈相加作用。方法：采用North-ernblot法分析心肌GLUT4mRNA，采用免疫印迹法分析心肌GLUT4基因表达。结果：输注胰岛素使局部低血流心肌GLUT4mRNA和GLUT4基因表达增加2.3-2.5倍,同时伴随心肌葡萄糖摄取明显增多达4倍.结论:胰岛素与低血流缺血刺激心肌致GLUT4mRNA和GLUT4表达呈相加作用,其结果使GLUT4数量明显增加,进而使心肌葡萄糖摄取量增加,此机制在缺血心肌能量代谢过程中起着重要的代谢性调节作用。

Additive e ffects of hyperinsulinemia and ischemia on canine myocardial GLUT4 gene expression in vivo

Objective: To investigate whether there is additive effects of hyperinsulinemia and ischemia on expression of canine myocardial GLUT4 gene in vivo . Methods: The expression of myocardial GLUT4 was determined by semiquantitative immunoblotting.The expression of GLUT4 mRNA was determined by semiquantitative Northern blotting. Results: Dramatic changes were seen in GLUT4 mRNA and GLUT4 expression in the ischemic hearts.After infusing insulin for 8 h,regional GLUT4 mRNA and GLUT4 levels in ischemic hearts were 2.5, 2.3 fold that of expression in normal hearts( P <0.01). Myocardial glucose uptake in ischemic hearts was increased by 4 fold when compared with normal hearts( P <0.01). Conclusion: There are not only additive effects of hyperinsulinemia and low flow ischemia on canine myocardial GLUT4 mRNA and GLUT4 expression in vivo , but also increase of myocardial glucose uptake. Enhanced GLUT4 expression may be an important protective mechanism by which myocardial cells enhance glucose uptake and metabolism during low flow ischemia. [