Repeated exercise regulates glucose transport capacity in skeletal muscle.
The present study was undertaken to test the hypothesis that a muscle's habitual level of contractile activity might act as a long-term regulator of glucose transport capacity. Rats were rendered severely diabetic by injection of streptozotocin, 125 mg kg-1 body wt. Three days after the injection, insulin-stimulated and contraction-induced 3-methylglucose transport in the in vitro epitrochlearis muscle preparation was reduced to 25% and 52% of control capacity, respectively (P less than 0.001). However, when repeated 1-h swimming sessions (twice a day) were introduced during the 3 days of insulin deficiency, the reduction in contraction-induced glucose transport capacity was completely abolished. This indicates that the habitual level of contractile activity of a muscle regulates its capacity for exercise-stimulated glucose transport. Furthermore, one exercise session and a maximal insulin stimulus had an additive effect on 3-methylglucose transport, suggesting that there are two pools of intracellular glucose transporters or two mechanisms for mobilizing the same pool.
D019325:3-O-Methylglucose; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology; D008297:Male; D008757:Methylglucosides / Q000378:metabolism; D009119:Muscle Contraction / Q000187:drug effects; D009132:Muscles / Q000378:metabolism*; D005082:Physical Exertion; D051381:Rats; D011919:Rats, Inbred Strains
D007328:Insulin; D008757:Methylglucosides; D019325:3-O-Methylglucose; D005947:Glucose