Prolonged exercise-induced stimulation of skeletal muscle glucose uptake is due to sustained increases in tissue perfusion and fractional glucose extraction.
BACKGROUND
The mechanisms behind the positive effects of physical activity on glucose metabolism in skeletal muscle and the time course of the effects need to be more elucidated.


OBJECTIVE
The aim was to examine the prolonged effects of an acute bout of one-legged exercise on local skeletal muscle glucose utilization and tissue perfusion.


METHODS
Interstitial glucose concentration, local tissue perfusion, glucose uptake, and effects of insulin infusion were studied 12 h after an acute bout of exercise and without prior exercise.


METHODS
Ten healthy subjects, five women and five men, participated in the study.


METHODS
Microdialysis measurements, (133)Xe clearance, and a 2-h hyperinsulinemic euglycemic clamp were performed on two occasions.


METHODS
We measured interstitial glucose concentration and tissue perfusion in the quadriceps femoris muscle of both legs.


RESULTS
Tissue perfusion (3.3 ± 0.6 ml × 100 g(-1) × min(-1) vs. 1.4 ± 0.2 ml × 100 g(-1) × min(-1); P = 0.007) and basal glucose uptake (2.3 ± 0.5 μmol × 100 g(-1) × min(-1) vs. 0.9 ± 0.2 μmol × 100 g(-1) × min(-1); P = 0.006) were increased in the leg that had exercised compared to the resting leg; the findings in the resting leg were comparable to those in the control experiment without prior exercise. The relative effect of insulin on fractional skeletal muscle glucose uptake was the same in all experimental settings, and insulin did not affect tissue perfusion.


CONCLUSIONS
The prolonged stimulatory effect of physical exercise on skeletal muscle glucose uptake was mediated via vascular effects combined with an increase in basal glucose transport independent of enhancement of insulin responses.
Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77 Stockholm, Sweden. Kerstin.Hamrin@gih.se
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K
Hamrin
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Qvisth
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Hagström-Toft
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Enoksson
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Henriksson
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Bolinder
D000328:Adult; D015444:Exercise / Q000502:physiology*; D005260:Female; D005947:Glucose / Q000302:isolation & purification / Q000378:metabolism / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D017551:Microdialysis; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000378:metabolism*; D010477:Perfusion; D005082:Physical Exertion / Q000502:physiology; D010812:Physical Stimulation; D012039:Regional Blood Flow / Q000502:physiology*; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors; D015854:Up-Regulation; D055815:Young Adult
D005947:Glucose