Expression of GLUT4 glucose transporter mRNA and protein in skeletal muscle and adipose tissue from rats in late pregnancy.

Abstract We investigated the influence of pregnancy on the expression of insulin-regulated glucose transporter (GLUT4) mRNA and protein in skeletal muscle and adipose tissue. GLUT4 mRNA expression in quadriceps muscle from control and pregnant rats was similar in the fasted and fed states. When the level of expression was determined as the immunoreactive GLUT4 content per gram of tissue, the relative GLUT4 protein content of red quadriceps from pregnant rats was significantly higher than that for control rats in both the fed and fasted states. GLUT4 protein expression in white quadriceps from pregnant rats was significantly increased in the fed state compared to control rats, but there was no significant difference in the fasted state. In adipose tissue, the relative GLUT4 protein content was significantly lower in pregnant rats than control rats in the fasted state, but there was no significant decrease in the fed state. Although the expression of GLUT4 protein showed these variations in late pregnancy, there was no significant difference of GLUT4 mRNA expression between control and pregnant rats. These findings suggest that GLUT4 kinetics may differ between late pregnancy and the normal state, and these changes may be related to insulin resistance in pregnancy.