[Dynamics of the change in Na, K-ATPase activity during the development of isoproterenol-induced myocardial necrosis in rats].

Na, K-ATPase activity of heart tissue homogenates was found to be depressed 6 and 24 h after the last injection of isoproterenol to rats (100 mg/kg s. c. daily for 2 consecutive days) whereas after 1 h it was essentially unchanged. The extent of the reduction in the enzyme activity was virtually the same both 6 and 24 h after myocardial necrosis induction (18 and 19%, respectively). The time-course of changes in the activity of the sarcolemmal marker enzyme was compared to the reported data on the increased sarcolemmal permeability in isoproterenol-induced myocardial necrosis.