Eccentric muscle damage transiently decreases rat skeletal muscle glut4 protein. Asp, Sven, Soren Kristiansen, and Erik A. Richter. Copenhagen Muscle Research Centre, August Krogh Institute, University of Copenhagen, 13 Universitetsparken, DK-2100, Copenhagen, Denmark
APStracts 2:0246A, 1995.
The effects of concentric and muscle damaging eccentric contractions on muscle GLUT4 content were studied in rat muscles. Rats were anaesthetized and the calf muscles on one side were stimulated electrically for concentric or eccentric contractions and bilateral calf muscles were obtained in the postexercise period. Inflammatory and phagocytic cells accumulated in the eccentric white and red gastrocnemius muscles, while there were only discrete changes in the eccentric soleus. Glycogen was depleted to the same extent in the white and red gastroc nemius muscles after both types of stimulation, and it remained decreased more than two days in eccentric muscles. The total GLUT4 protein content was decreased in the eccentric white and red gastrocnemius muscles one and two days after the eccentric stimulation, whereas the maximal activity of glycogen synthase was unaffected at these time points. In conclusion our one-legged stimulation model caused eccentric muscle damage in the white and red gastroc nemius, whereas only minor damage was observed in the soleus muscle. In damaged muscle, muscle glycogen and GLUT4 protein content were decreased for more than two days. These findings may suggest - but do not prove - that decreased muscle GLUT4 protein is involved in the delayed glycogen resynthesis after eccentric exercise. 

Received 6 February 1995; accepted in final form 31 May 1995.
APS Manuscript Number A137-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on  6 July 1995.