[Protein fractions and their enzymatic activity in the rat myocardium after a flight on the Cosmos-690 biosatellite].

Gamma-irradiation of rats in the ground-based experiment decreased the activity of aspartate aminotransferase of sarcoplasmatic proteins of the myocardium and increased the activity of adenosine triphosphate of myosin of the myocardium 1 and 26 days post-test. Gamma-irradiation of flight rats also reduced the activity of aspartate aminotransferase of sarcoplasmatic proteins of the myocardium; however, the activity of ATPase of myosin of the myocardium was lowered both 1 and 26 days postflight. It is suggested that irradiation-induced inhibition of synthetic processes delayed the synthesis of myosin with a normal activity and diminished the protein content in the T fraction of myocardium on the 1st postflight day.