TY - JOUR

T1 - IMP metabolism in human skeletal muscle after exhaustive exercise

AU - Tullson, P. C.

AU - Bangsbo, Jens

AU - Hellsten, Ylva

AU - Richter, Erik A.

N1 - Keywords: AMP Deaminase; Adult; Ammonia; Bicycling; Body Composition; Exercise; Humans; Hypoxanthines; Inosine Monophosphate; Lactates; Male; Muscle Fibers, Skeletal; Muscle, Skeletal; Purines; Regional Blood Flow

PY - 1995

Y1 - 1995

N2 - This study addressed whether AMP deaminase (AMPD)myosin binding occurs with deamination during intense exercise in humans and the extent of purine loss from muscle during the initial minutes of recovery. Male subjects performed cycle exercise (265 +/- 2 W for 4.39 +/- 0.04 min) to stimulate muscle inosine 5'-monophosphate (IMP) formation. After exercise, blood flow to one leg was occluded. Muscle biopsies (vastus lateralis) were taken before and 3.6 +/- 0.2 min after exercise from the occluded leg and 0.7 +/- 0.0, 1.1 +/- 0.0, and 2.9 +/- 0.1 min postexercise in the nonoccluded leg. Exercise activated AMPD; at exhaustion IMP was 3.5 +/- 0.4 mmol/kg dry muscle. Before exercise, 16.0 +/- 1.6% of AMPD cosedimented with the myosin fraction; the extent of AMPD:myosin binding was unchanged by exercise. Inosine content increased about threefold during exercise and twofold more during recovery; by 2.9 min postexercise it was 0.43 +/- 0.02 mmol/kg dry muscle. IMP decreased 2.1 +/- 0.3 mmol/kg dry muscle with no change in total adenylates. Total purines declined significantly (P < 0.05) during the recovery period in the nonoccluded leg, consistent with a loss of purines to the circulation, whereas total purines were unchanged in the occluded leg. Regulation of muscle purine content is a dynamic process that must accommodate rapid changes due to degradation and efflux.

AB - This study addressed whether AMP deaminase (AMPD)myosin binding occurs with deamination during intense exercise in humans and the extent of purine loss from muscle during the initial minutes of recovery. Male subjects performed cycle exercise (265 +/- 2 W for 4.39 +/- 0.04 min) to stimulate muscle inosine 5'-monophosphate (IMP) formation. After exercise, blood flow to one leg was occluded. Muscle biopsies (vastus lateralis) were taken before and 3.6 +/- 0.2 min after exercise from the occluded leg and 0.7 +/- 0.0, 1.1 +/- 0.0, and 2.9 +/- 0.1 min postexercise in the nonoccluded leg. Exercise activated AMPD; at exhaustion IMP was 3.5 +/- 0.4 mmol/kg dry muscle. Before exercise, 16.0 +/- 1.6% of AMPD cosedimented with the myosin fraction; the extent of AMPD:myosin binding was unchanged by exercise. Inosine content increased about threefold during exercise and twofold more during recovery; by 2.9 min postexercise it was 0.43 +/- 0.02 mmol/kg dry muscle. IMP decreased 2.1 +/- 0.3 mmol/kg dry muscle with no change in total adenylates. Total purines declined significantly (P < 0.05) during the recovery period in the nonoccluded leg, consistent with a loss of purines to the circulation, whereas total purines were unchanged in the occluded leg. Regulation of muscle purine content is a dynamic process that must accommodate rapid changes due to degradation and efflux.

M3 - Journal article

C2 - 7713804

VL - 78

SP - 146

EP - 152

JO - Journal of Applied Physiology

JF - Journal of Applied Physiology

SN - 8750-7587

IS - 1

ER -