The present study examined the mRNA levels of glucose transporter Glut4 and G-protein Gs α-subunit in isolated ventricular myocytes from lean and genetically obese (fa/fa) Zucker rats and streptozotocin-diabetic rats. In obese animals the amount of transcripts coding for Glut4 increased to 122±6% of lean controls, whereas the mRNA coding for Gs α-subunit decreased by 42±12%. An unaltered level of Gs mRNA was observed in insulin deficient rats. When cardiomyocytes from normal rats were treated with insulin, the Glut4 transcript level increased by 48±5%, whereas the Gs mRNA level decreased by 55±8%. The findings suggest that insulin may act as a potential regulator of Glut4 and Gs mRNA expression in the cardiac cell.
