title: Effect of exercise on amino acid incorporation into myocardial contractile proteins.
abstract: Amino acid incorporation into myocardial protein was studied in rats after an acute bout of exhaustive swimming. Hearts were removed at exhaustion, 1, 2, or 4 h of recovery and amino acid incorporation measured using [3H] phenylalanine in an isolated perfused heart preparation. Amino acid incorporation into total tissue protein was reduced 30% at exhaustion but returned to normal by 1 h of recovery and showed no further change 4 h post exercise. In the myofibrillar fraction amino acid incorporation decreased slightly after exhaustive exercise but was stimulated by 57% following 2 h recovery. Myosin, electrophoretically fractionated showed an 84% stimulation in phenylalanine incorporation at exhaustion and 112% increase 2 h post exercise. Amino acid incorporation into myosin light chains (LC1 and LC2) accounted for most of the increased rate of synthesis. These data suggest that there was a preferential increase in myocardial protein synthesis following exercise which was associated with the myosin light chain components of the contractile proteins.
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D005260:Female; D066298:In Vitro Techniques; D007700:Kinetics; D008970:Molecular Weight; D009124:Muscle Proteins / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D009210:Myofibrils / Q000378:metabolism; D009218:Myosins / Q000378:metabolism; D010649:Phenylalanine / Q000378:metabolism; D005082:Physical Exertion; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D000596:Amino Acids; D009124:Muscle Proteins; D010649:Phenylalanine; D009218:Myosins