Objective:To investigate the mechanism of increased glucose uptake, the expression of myoc ardial glucose transporter1 (GLUT1) was determined after low-flow myocardial is chemia. Methods: An in vivo open-chest canine model of low -flow myocardial ischemia was used to correlate myocardial glucose uptake with the number of GLUT1. The expression of myocardial GLUT1 glucose transporter was determined by semiquantitative Northern blotting and immunoblotting. Res ults: GLUT1 mRNA and GLUT1 polypeptide expression was substantially inc reased in ischemic region from the experimental hearts when compared to normal h earts. There was no significant regional difference in GLUT1 expression in eith er normal or ischemic hearts.Conclusion:Myocardial ischemia ind uces a factor or factors which stimulate GLUT1 expression in ischemic myocardial regions. Enhanced GLUT1 expression may be an important protective mechanism by which myocardial cells enhance glucose uptake and metabolism during low-flow my ocardial ischemia.