Eccentric contractions impair subsequent contraction-induced glucose transport in rat skeletal muscle: relation to glut4 content. Kristiansen, S[stod]oren, Sven Asp, and Erik A. Richter. Copenhagen Muscle Research Centre, August Krogh Institute, University of Copenhagen, 13 Universitetsparken, DK-2100 Copenhagen, Denmark
APStracts 3:0103R, 1996.
Eccentric exercise causes muscle damage and decreased muscle glycogen and GLUT4 protein content. We investigated whether the contraction -induced increase in skeletal muscle glucose transport and muscle performance is affected by prior eccentric contractions. The calf muscles from rats were stimulated for eccentric (EC) or concentric (CC) contractions or were passively stretched (ST). Muscles from unstimulated control (CT) rats were also studied. Two days later all rats had their isolated hindlimbs perfused either at rest or during 15 min of isometric muscle contractions. EC rats had a significantly lower total GLUT4 protein content in the white gastrocnemius (GW) muscle (55%) and red gastrocnemius (GR) muscle (34 %), compared with muscle from the CT, ST, and CC rats. In contrast, GLUT1 protein content was approximatively 2 fold higher in the GW muscle in EC rats than in CT rats. In the GW and GR muscle prior eccentric exercise decreased contraction-induced stimulation of glucose transport compared with CT, ST and CC rats in spite of no difference in tension development and oxygen uptake among the groups. There was no change in total GLUT4 content and glucose transport in the soleus (S) muscle among the 4 groups. It is concluded that the GLUT4 and GLUT1 protein content in fast-twitch muscle are decreased and increased, respectively, two days after eccentric contractions. The functional consequence of these changes appears to be decreased contraction -induced increase in skeletal muscle glucose transport.

Received 16 October 1995; accepted in final form 19 February
1996.
APS Manuscript Number R655-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 27 March 96