Contraction-stimulated muscle glucose transport and GLUT-4 surface content are dependent on glycogen content.
The influence of muscle glycogen content on basal and contraction-induced glucose transport and cell surface GLUT-4 content was studied in rat skeletal muscle. Wistar rats were preconditioned by a combination of swimming exercise and diet, resulting in 40% lower (LG) or threefold higher (HG) muscle glycogen content compared with nonexercised controls (NG). At rest and during contractions, 2-deoxy-D-glucose uptake in perfused fast-twitch muscle, but not slow-twitch muscle, was significantly lower in HG compared with LG. Cell surface GLUT-4 content in the fast-twitch plantaris was 994 +/- 180, 1,173 +/- 311, and 2,155 +/- 243 dpm/g in the basal condition and increased (P < 0.05) to 2,285 +/- 239, 3,230 +/- 464, and 4,847 +/- 654 dpm/g during contractions with HG, NG, and LG, respectively, the increase being significantly smaller in HG compared with LG. The contraction-induced increments in glucose transport and in cell surface GLUT-4 content were negatively correlated with the initial glycogen content (P <0.01). In conclusion, glucose transport and cell surface GLUT-4 content in resting and contracting fast-twitch muscle are dependent on the muscle glycogen content.
Derave
W
W
Copenhagen Muscle Research Centre, August Krogh Institute, University of Copenhagen, 2100 Copenhagen, Denmark.
Lund
S
S
Holman
G D
GD
Wojtaszewski
J
J
Pedersen
O
O
Richter
E A
EA
D000818:Animals; D000963:Antimetabolites / Q000493:pharmacokinetics; D001692:Biological Transport / Q000502:physiology; D001835:Body Weight; D003847:Deoxyglucose / Q000493:pharmacokinetics; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4; D006003:Glycogen / Q000378:metabolism*; D006614:Hindlimb; D066298:In Vitro Techniques; D008297:Male; D008565:Membrane Proteins / Q000032:analysis / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000032:analysis / Q000378:metabolism*; D009119:Muscle Contraction / Q000502:physiology*; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D010477:Perfusion; D005082:Physical Exertion / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
D000963:Antimetabolites; D051275:Glucose Transporter Type 4; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495694:Slc2a4 protein, rat; D006003:Glycogen; D003847:Deoxyglucose; D005947:Glucose