Effects of acute exercise and detraining on insulin action in trained men.
Seven endurance-trained subjects [maximal O2 consumption (VO2max) 64 +/- 1 (SE) ml.min-1.kg-1] underwent sequential hyperinsulinemic euglycemic clamps on three occasions: 1) in the "habitual state" 15 h after the last training bout (C), 2) after 60 min of bicycle exercise at 72 +/- 3% of VO2max performed in the habitual state (E), and 3) 5 days after the last ordinary training session (detrained, DT). Sensitivity for insulin-mediated whole-body glucose uptake was not affected by acute exercise [insulin concentrations eliciting 50% of maximal insulin-mediated glucose uptake being 44 +/- 2 (C) vs. 46 +/- 3 (E) microU/ml] but was decreased after detraining (54 +/- 2 microU/ml, P less than 0.05) to levels comparable to those found in untrained subjects [Am. J. Physiol. 254 (Endocrinol. Metab. 17): E248-E259, 1988]. Near-maximal insulin-mediated glucose uptake (responsiveness) was higher than in untrained subjects and not influenced by acute exercise or detraining [13.4 +/- 1.2 (C), 12.2 +/- 0.9 (E), and 12.2 +/- 0.3 (DT) mg.min-1.kg-1]. Calculated by indirect calorimetry, the glucose-to-glycogen conversion was not influenced by E but was reduced during detraining (P less than 0.05) yet remained higher than previously found in untrained subjects (P less than 0.05). However, only on E days did muscle glycogen increase during insulin infusion. Glycogen synthase activity was increased on E and decreased on DT compared with C days.(ABSTRACT TRUNCATED AT 250 WORDS)
Mikines
K J
KJ
Department of Medical Physiology B, Panum Institute, University of Copenhagen, Denmark.
Sonne
B
B
Tronier
B
B
Galbo
H
H
D001693:Biological Transport, Active / Q000187:drug effects; D001786:Blood Glucose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism / Q000493:pharmacokinetics*; D006006:Glycogen Synthase / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D009132:Muscles / Q000187:drug effects / Q000378:metabolism; D010807:Physical Endurance; D005082:Physical Exertion
D001786:Blood Glucose; D007328:Insulin; D006006:Glycogen Synthase; D005947:Glucose