ABSTRACT
Objective: To investigate whether there is additi ve effects of hyperinsulinemia and ischemia on expression of canine myocardial G LUT4 gene in vivo. Methods: The expression of myocardial GLU T4 was determined by semiquantitative immunoblotting.The expression of GLUT4 mRN A was determined by semiquantitative Northern blotting. Results: Dramatic changes were seen in GLUT4 mRNA and GLUT4 expression in the ischemic hearts.After infusing insulin for 8 h,regional GLUT4 mRNA and GLUT4 levels in is chemic hearts were 2.5, 2.3-fold that of expression in normal hearts(P<0.01 ). Myocardial glucose uptake in ischemic hearts was increased by 4-fold when co mpared with normal hearts(P<0.01). Conclusion: There are not only additive effects of hyperinsulinemia and low-flow ischemia on canine myoc ardial GLUT4 mRNA and GLUT4 expression in vivo, but also increase of myocar dial glucose uptake. Enhanced GLUT4 expression may be an important protective m echanism by which myocardial cells enhance glucose uptake and metabolism during low-flow ischemia.
ABSTRACT
Objective: To investigate whether insulin stimulates the translocation of glucose transporter-4 (GLUT4) and glucose uptak e in ischemic myocardium. Methods: Plasma concentration of gluc ose, lactate, free fatty acid and insulin were determined by autoanalyser, and G LUT4 was studied by Western blotting analysis. Results: Insulin increased GLUT4 significantly in sarcolemma of ischemic myocardium ［(25±4)% vs (40±6)%］, and GLUT4 content in intracellular membrane decreased proporti onally. The glucose uptake increased significantly in insulin-ischemic myocardi um. The uptake of insulin-ischemic myocardium was almost 2 times that of ischem ic myocardium. Conclusion: Insulin stimulation results in GLUT4 translocation and increases glucose uptake in ischemic myocardium. When myocardi al ischemia occurs, insulin is helpful in increasing myocardial glucose uptake a nd utilization.
ABSTRACT
Objective: To investigate whether there is additi ve effects of hyperinsulinemia and ischemia on expression of canine myocardial G LUT4 gene in vivo. Methods: The expression of myocardial GLU T4 was determined by semiquantitative immunoblotting.The expression of GLUT4 mRN A was determined by semiquantitative Northern blotting. Results: Dramatic changes were seen in GLUT4 mRNA and GLUT4 expression in the ischemic hearts.After infusing insulin for 8 h,regional GLUT4 mRNA and GLUT4 levels in is chemic hearts were 2.5, 2.3-fold that of expression in normal hearts(P<0.01 ). Myocardial glucose uptake in ischemic hearts was increased by 4-fold when co mpared with normal hearts(P<0.01). Conclusion: There are not only additive effects of hyperinsulinemia and low-flow ischemia on canine myoc ardial GLUT4 mRNA and GLUT4 expression in vivo, but also increase of myocar dial glucose uptake. Enhanced GLUT4 expression may be an important protective m echanism by which myocardial cells enhance glucose uptake and metabolism during low-flow ischemia.
ABSTRACT
Objective: To investigate whether insulin stimulates the translocation of glucose transporter-4 (GLUT4) and glucose uptak e in ischemic myocardium. Methods: Plasma concentration of gluc ose, lactate, free fatty acid and insulin were determined by autoanalyser, and G LUT4 was studied by Western blotting analysis. Results: Insulin increased GLUT4 significantly in sarcolemma of ischemic myocardium ［(25±4)% vs (40±6)%］, and GLUT4 content in intracellular membrane decreased proporti onally. The glucose uptake increased significantly in insulin-ischemic myocardi um. The uptake of insulin-ischemic myocardium was almost 2 times that of ischem ic myocardium. Conclusion: Insulin stimulation results in GLUT4 translocation and increases glucose uptake in ischemic myocardium. When myocardi al ischemia occurs, insulin is helpful in increasing myocardial glucose uptake a nd utilization.