Incorporation of 14C-adenine to cyclic 3',5'-AMP of cardiac muscle in isoprenaline-induced experimental cardiomyopathy.

Experimental cardiomyopathy was produced by isoprenaline (2 x 80 mg/kg sc daily for 2 days). The degree of myocardial damage was evaluated histopathologically. In the damaged cardiac muscle the incorporation of 14C-adenine was impaired, the adenylate cyclase activity was diminished and the total contents of cAMP and 14C-cAMP formed from intracellular 14C-adenine metabolism were reduced. No significant changes in the activity of phosphodiesterase were found. This indicates that cAMP synthesis is impaired as a result of decreased utilization of the ATP pool formed from exogenous adenine in the cardiac muscle damaged by isoprenaline.