Difference between senescence-accelerated prone and resistant mice in response to insulin in the heart

Abstract The effect of insulin on the translocation of GLUT4 (glucose transporter isoform 4) from the intracellular membranes to the plasma membranes was compared in the hearts of 4–8 week old SAMP8, a substrain of senescence-accelerated prone mouse and those of SAMR1, a substrain of senescence-accelerated resistant mouse. After 20 min of the intravenous injection of insulin, the blood glucose levels in SAMR1 and SAMP8 were decreased by 50 and 68%, respectively. Under this condition, the concentrations of GLUT4 protein in the plasma membranes in the hearts of SAMR1 and SAMP8 were increased 1.8- and 2.1-fold, respectively. Concomitantly, the concentrations of the GLUT4 protein in the intracellular membranes in the hearts of SAMR1 and SAMP8 were decreased by about 70 and 50%, respectively. These results suggest that the heart of 4–8 week old SAMP8 is more sensitive to insulin than that of age-matched SAMR1.