胰岛素对在体犬缺血心肌GLUT1基因表达呈协同作用

Additive effects of hyperinsulinemia and ischemia on GLUT1 gene expression in canine heart in vivo

目的 :观察胰岛素对缺血心肌葡萄糖转运子 1(GLUT1)基因表达是否有协同作用。方法 :采用Northern法分析心肌GLUT1mRNA和免疫法分析心肌GLUT1多肽。结果 :输注胰岛素使局部低血流心肌GLUT1mRNA和GLUT1多肽表达增加 4 2～ 2倍。同时伴随心肌葡萄糖摄取明显增多。结论 :胰岛素对低血流缺血刺激心肌GLUT1mRNA和GLUT1多肽表达呈协同作用 ,其结果使心肌葡萄糖摄取量增多。胰岛素对低血流缺血刺激心肌GLUT1表达的协同作用 ,在缺血心肌能量代谢过程中起着重要的调节作用。

Objective:To investigated if there was additive effects of hyperinsulinemia and ischemia on the expression of canine myocardial GLUT1 glucose transporter in vivo.Method:The expression of myocardial GLUT1mRNA was determined by semiquantitative Northern blotting.The expression of myocardia GLUT1 polypeptide was determined by semiquantitative immunoblotting.Result:More dramatic changes were seen in GLUT1mRNA and GLUT1 polypeptide expression in the ischemic hearts.After infusion insulin for a total of 8 h,regional GLUT1mRNA and GLUT1 polypeptide levels in ischemic hearts were 4.2～2 fold that of expression in normal hearts ( P <0.01).Myocardial glucose up take in ischemic hearts was increased 4-fold when compared to that of normal hearts( P< 0.01).Conclusion:Insulin and low-flow ischemia have additive effects to stimulate in vivo GLUT1mRNA and GLUT1 polypeptide expression.The authors conclude that expression of GLUT1 contributes to increase GLUT1 translocation and myocardial glucose uptake during low-flow myocardial ischemia under insuli-stimulated conditions.