title: Eccentric exercise decreases glucose transporter GLUT4 protein in human skeletal muscle.
abstract: 1. Eccentric exercise causes impaired postexercise glycogen resynthesis. To study whether changes in muscle concentration of the glucose transporter (GLUT4) protein might be involved, seven healthy young men performed one-legged eccentric exercise by resisting knee flexion enforced by a motor-driven device. 2. The GLUT4 protein concentration in the exercised and in the control thigh was unchanged immediately after exercise. On days 1 and 2 after exercise, the GLUT4 protein concentration in the exercised muscle was 68 +/- 10 and 64 +/- 10% (means +/- S.E.M.; P < 0.05), respectively, of the concentration in the control muscle, and had returned to control values on days 4 and 7. 3. The muscle glycogen concentration decreased from 404 +/- 44 to 336 +/- 44 mmol (kg dry wt)-1 (P < 0.05) during exercise. The glycogen concentration remained significantly lower than in the control thigh on days 1 and 2 after exercise but on days 4 and 7 no differences were found. 4. Although no cause-effect relationship was established, these findings may suggest that decreased muscle concentrations of GLUT4 protein, and, hence, a decreased rate of glucose transport into muscle cells, may be involved in the sustained low glycogen concentration seen after eccentric exercise.
authors.affiliation: Copenhagen Muscle Research Centre, August Krogh Institute, University of Copenhagen, Denmark.
authors.forename: S
authors.initials: S
authors.lastname: Asp
authors.forename: J R
authors.initials: JR
authors.lastname: Daugaard
authors.forename: E A
authors.initials: EA
authors.lastname: Richter
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D015153:Blotting, Western; D002395:Catecholamines / Q000378:metabolism; D003402:Creatine Kinase / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D015444:Exercise / Q000502:physiology*; D051275:Glucose Transporter Type 4; D006003:Glycogen / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D002395:Catecholamines; D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495692:SLC2A4 protein, human; D006003:Glycogen; D003402:Creatine Kinase