Prior exercise in humans redistributes intramuscular GLUT4 and enhances insulin-stimulated sarcolemmal and endosomal GLUT4 translocation
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Objective: Exercise is a cornerstone in the management of skeletal muscle insulin-resistance. A well-established benefit of a single bout of exercise is increased insulin sensitivity for hours post-exercise in the previously exercised musculature. Although rodent studies suggest that the insulin-sensitization phenomenon involves enhanced insulin-stimulated GLUT4 cell surface translocation and might involve intramuscular redistribution of GLUT4, the conservation to humans is unknown.
Methods: Healthy young males underwent an insulin-sensitizing one-legged kicking exercise bout for 1 hour followed by fatigue bouts to exhaustion. Muscle biopsies were obtained 4h post-exercise before and after a 2h hyperinsulinemic-euglycemic clamp.
Results: A detailed microscopy-based analysis of GLUT4 distribution muscle specimen in 7 different myocellular compartments revealed that prior exercise increased GLUT4 localization in insulin-responsive storage vesicles and T-tubuli. Furthermore, insulin-stimulated GLUT4 localization was augmented at the sarcolemma and in the endosomal compartments.
Conclusion: An intracellular redistribution of GLUT4 post-exercise is proposed as a molecular mechanism contributing to the insulin-sensitizing effect of prior exercise in human skeletal muscle.
|Number of pages||9|
|Publication status||E-pub ahead of print - 16 Apr 2020|
Copyright © 2020 The Author(s). Published by Elsevier GmbH.. All rights reserved.
- Faculty of Science - Exercise, Skeletal muscle, GLUT4, Insulin sensitivity, Insulin resistance