Eccentric muscle damage transiently decreases rat skeletal muscle GLUT-4 protein.
The effects of concentric and muscle-damaging eccentric contractions on muscle glucose transporter GLUT-4 content were studied in rat muscles. Rats were anesthetized, 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, whereas there were only discrete changes in the eccentric soleus. Glycogen was depleted to the same extent in the white and red gastrocnemius muscles after both types of stimulation, and it remained decreased > 2 days in eccentric muscles. The total GLUT-4 protein content was decreased in the eccentric white and red gastrocnemius muscles 1 and 2 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 gastrocnemius, whereas only minor damage was observed in the soleus muscle. In damaged muscle, muscle glycogen and GLUT-4 protein content were decreased for > 2 days. These findings may suggest (but do not prove) that decreased muscle GLUT-4 protein is involved in the delayed glycogen resynthesis after eccentric exercise.
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Copenhagen Muscle Research Centre, August Krogh Institute, University of Copenhagen, Denmark.
Kristiansen
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Richter
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D000818:Animals; D001834:Body Water / Q000378:metabolism; D004558:Electric Stimulation; D051275:Glucose Transporter Type 4; D006003:Glycogen / Q000378:metabolism; D006006:Glycogen Synthase / Q000037:antagonists & inhibitors; D008297:Male; D008566:Membranes / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009119:Muscle Contraction / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000293:injuries* / Q000378:metabolism* / Q000473:pathology; D010586:Phagocytes / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
D051275:Glucose Transporter Type 4; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495694:Slc2a4 protein, rat; D006003:Glycogen; D006006:Glycogen Synthase