[Effect of isobutylmethylxanthine on the adenylate cyclase system of the myocardium and skeletal muscles of the rat during the recovery period following physical loading].

The in vivo experiments established that isobutyl methyl xanthine inhibits phosphodiesterase activity and activates adenylate cyclase in the skeletal muscles and myocardium. The preparation prevents phosphodiesterase activity from increasing due to physical exercises. Against a background of the latter it activates adenylate cyclase and prevents the cAMP level from declining in skeletal muscles. In the myocardium this effect of isobutyl methyl xanthine is less pronounced.