The study of intrinsic activity of glucose transporter 4 (GluT4) regulated by insulin in skeletal muscle cells / 中国糖尿病杂志

ABSTRACT

Objective To study the mechanism of insulin-stimulated glucose uptake in skeletal muscle cells. Methods The responses of GluT4 translocation and glucose uptake to the investigational drugs of SB203580 and Wortmannin as well as the effect of insulin on the drugs during differentiation were detected to study the insulin signal pathway. Results The GluT4 translocation and glucose transport were increased under insulin stimulation by 2.5±0.2 and 2.2±0.1 folds, respectively while compared with control; but t1/2 were 3.3 min and 6.0 min, and IC50 to wortmannin were 43 nmol/L and 3 nmol/L respectively.SB203580 inhibited 64% and 62% of insulin-stimulated glucose uptake and photolabelling of cell surface GluT4, respectively, but had no effect on GluT4 translocation.The fold increase of insulin-stimulated glucose uptake (1.7±0.1 fold vs control)was lower than that of GluT4 translocation (2.3±0.1 fold vs control) in myoblasts. Conclusions In skeletal muscle cells, two insulin signal pathways mediate GluT4 translocation and activation of GluT4, respectively.Insulin engages both of the pathways to stimulate the cells for maximum glucose uptake.