title: Decreased insulin action on muscle glucose transport after eccentric contractions in rats.
abstract: We have recently shown that eccentric contractions (Ecc) of rat calf muscles cause muscle damage and decreased glycogen and glucose transporter GLUT-4 protein content in the white (WG) and red gastrocnemius (RG) but not in the soleus (S) (S. Asp, S. Kristiansen, and E. A. Richter. J. Appl. Physiol. 79: 1338-1345, 1995). To study whether these changes affect insulin action, hindlimbs were perfused at three different insulin concentrations (0, 200, and 20,000 microU/ml) 2 days after one-legged eccentric contractions of the calf muscles. Compared with control, basal glucose transport was slightly higher (P < 0.05) in Ecc-WG and -RG, whereas it was lower (P < 0.05) at both submaximal and maximal insulin concentrations in the Ecc-WG and at maximal concentrations in the Ecc-RG. In the Ecc-S, the glucose transport was unchanged in hindquarters perfused in the absence or presence of a submaximal stimulating concentration of insulin, whereas it was slightly (P < 0.05) higher during maximal insulin stimulation compared with control S. At the end of perfusion the glycogen concentrations were lower in both Ecc-gastrocnemius muscles compared with control muscles at all insulin concentrations. Fractional velocity of glycogen synthase increased similarly with increasing insulin concentrations in Ecc- and control WG and RG. We conclude that insulin action on glucose transport but not glycogen synthase activity is impaired in perfused muscle exposed to prior eccentric contractions.
authors.affiliation: Copenhagen Muscle Research Centre, August Krogh Institute, University of Copenhagen, Denmark. sasp@aki.ku.dk
authors.forename: S
authors.initials: S
authors.lastname: Asp
authors.forename: E A
authors.initials: EA
authors.lastname: Richter
mesh_terms: D000818:Animals; D001834:Body Water / Q000502:physiology; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4; D006003:Glycogen / Q000378:metabolism; D006006:Glycogen Synthase / Q000378:metabolism; D006614:Hindlimb / Q000098:blood supply; D007333:Insulin Resistance / Q000502:physiology*; D007866:Leg / Q000502:physiology; D008297:Male; D008353:Mannitol; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D009119:Muscle Contraction / Q000502:physiology; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012039:Regional Blood Flow / Q000502:physiology
chemical_list: D051275:Glucose Transporter Type 4; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495694:Slc2a4 protein, rat; D008353:Mannitol; D006003:Glycogen; D006006:Glycogen Synthase; D005947:Glucose