Bryer-Ash M
Department of Medicine, University of California, San Diego.
Diabetes. 1989 Jan;38(1):108-16. doi: 10.2337/diab.38.1.108.
Tyrosine kinase activity of skeletal muscle-derived insulin receptors isolated from rats that had undergone euglycemic clamps at various insulin infusion rates was examined. Receptors were isolated under conditions designed to preserve their in vivo phosphorylation state, and their kinase activity toward histone was measured in the absence of in vitro exposure to insulin. Results showed that significant activation of the insulin-receptor kinase occurred after exposure in vivo to mean serum insulin concentrations as low as 34 +/- 3.5 microU/ml and that maximal activation was achieved by insulin levels less than or equal to 2000 microU/ml. There was a highly significant correlation between receptor kinase activity and serum insulin concentration in the physiologic range (r = .92, P less than .0001) and between kinase activity and glucose utilization rate (r = .74, P less than .0001). These findings further support a role for the insulin-receptor kinase in insulin action in vivo, and this model provides a novel method for the study of the effect of factors known to influence insulin action on the insulin-receptor kinase under physiologic conditions.
对从以不同胰岛素输注速率进行正常血糖钳夹的大鼠分离出的骨骼肌源性胰岛素受体的酪氨酸激酶活性进行了检测。在旨在保留其体内磷酸化状态的条件下分离受体，并在未进行体外胰岛素暴露的情况下测量其对组蛋白的激酶活性。结果显示，在体内暴露于低至34±3.5微单位/毫升的平均血清胰岛素浓度后，胰岛素受体激酶发生了显著激活，且胰岛素水平小于或等于2000微单位/毫升时达到最大激活。在生理范围内，受体激酶活性与血清胰岛素浓度之间存在高度显著的相关性（r = 0.92，P < 0.0001），激酶活性与葡萄糖利用率之间也存在高度显著的相关性（r = 0.74，P < 0.0001）。这些发现进一步支持了胰岛素受体激酶在体内胰岛素作用中的作用，并且该模型为研究已知影响胰岛素作用的因素在生理条件下对胰岛素受体激酶的作用提供了一种新方法。
