APStracts 3:0217E, 1996.

Progressive increase in glucose transport and glut4 in human sarcolemmal vesicles during moderate exercise. Kristiansen, Sren, Mark Hargreaves, and Erik A. Richter. Copenhagen Muscle Research Centre, August Krogh Institute, University of Copenhagen, 13 Universitetsparken, DK-2100, Copenhagen, Denmark

APStracts 3:0217E, 1996.

Muscle glucose uptake increases progressively during moderate intensity exercise. To elucidate whether this is due to a progressive increase in sarcolemmal glucose transport capacity, nine men exercised for 40 min at 75% VO2 max on a bicycle ergometer. Muscle biopsies were obtained from the vastus lateralis at rest (0 min), after 5 and 40 min of exercise and used for production of sarcolemmal giant (SG) vesicles. SG vesicle glucose transport at 5 mM increased (p&LT;0.05) by 38% and 93% after 5 and 40 min of exercise, respectively, compared with glucose transport at rest. The SG vesicle GLUT4 protein content increased (p&LT;0.05) by 36% and 91% after 5 and 40 min of exercise, respectively, compared with rest. Thus, the increase in vesicle glucose transport was accompanied by a similar increase in SG vesicle GLUT4 protein content. Muscle glucose and glucose-6-phosphate (G-6P) were low at rest, increased (p&LT;0.05) 2.2 and 2.3 fold, respectively, after 5 min of exercise and returned to resting values after 40 min of exercise. It is concluded that the progressive increase in muscle glucose uptake during moderate intensity exercise, at least in part, may be due to a progressive increase in sarcolemmal glucose transport and GLUT4 protein content.

Received 30 July 1996; accepted in final form 25 October 1996.
APS Manuscript Number E367-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 November 1996