Creatine, exercice et synthese proteique musculaire Creatine, exercise and muscle protein synthesis

摘要

Aims.-To evaluate the effects of creatine supplementation on the metabolism protidic during the exercise.Materials and methods.-Seven young healthy men performed on two occasions 20 x 10 repetitions of one leg extension-flexion at 7.5% one-repetition maximum, the resting leg being the control. Before one of the two experiments, the subject ingested creatine (21 g per day for 5 days). The subjects ate 21 g maltodextrin + 6 g protein per h for 3 h postexercise period. The subjects were perfused with [l-13C]-leucine and [2H5]-phenylalanine. Biopsy samples were taken from the vastus lateralis and arterial and venous blood samples were drawn. Proteins synthesis and breakdown were calculated for the rested and exercised leg. Creatine supplementation increased muscle total creatine by about 21% (p < 0.01). Exercise increased the synthetic rates of myoflbrillar and sarcoplasmic proteins by two- to three-fold (p < 0.05) and the leg phenylalanine balance became more positive, but creatine was without any anabolic effect.