Effects of continuous low-carbohydrate diet after long-term exercise on GLUT-4 protein content in rat skeletal muscle.
Stimulation of AMPK and decreased glycogen levels in skeletal muscle have a deep involvement in enhanced insulin action and GLUT-4 protein content after exercise training. The present study examined the chronic effects of a continuous low-carbohydrate diet after long-term exercise on GLUT-4 protein content, glycogen content, AMPK, and insulin signaling in skeletal muscle. Rats were divided randomly into four groups: normal chow diet sedentary (N-Sed), low carbohydrate diet sedentary (L-Sed), normal chow diet exercise (N-Ex), and low carbohydrate diet exercise (L-Ex) groups. Rats in the exercise groups (N-Ex and L-Ex) were exercised by swimming for 6 hours/day in two 3-hour bouts separated by 45 minutes of rest. The 10-day exercise training resulted in a significant increase in the GLUT-4 protein content (p<0.01). Additionally, the GLUT-4 protein content in L-Ex rats was increased by 29% above that in N-Ex rats (p<0.01). Finally, the glycogen content in skeletal muscle of L-Ex rats was decreased compared with that of N-Ex rats. Taken together, we suggest that the maintenance of glycogen depletion after exercise by continuous low carbohydrate diet results in the increment of the GLUT-4 protein content in skeletal muscle.
Kubota
M
M
Department of Health Science, Faculty of Medicine, Kyoto University, Kyoto, Japan.
Koshinaka
K
K
Kawata
Y
Y
Koike
T
T
Oshida
Y
Y
D055372:AMP-Activated Protein Kinases; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D001786:Blood Glucose; D050528:Diet, Carbohydrate-Restricted; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D006003:Glycogen / Q000378:metabolism; D055504:Insulin Receptor Substrate Proteins; D008297:Male; D009097:Multienzyme Complexes / Q000378:metabolism; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism*; D010766:Phosphorylation; D010805:Physical Conditioning, Animal; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D048868:Adaptor Proteins, Signal Transducing; D001786:Blood Glucose; D051275:Glucose Transporter Type 4; D055504:Insulin Receptor Substrate Proteins; C526296:Irs1 protein, rat; D009097:Multienzyme Complexes; D006003:Glycogen; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases