Inhibition of rat heart and brain cyclic adenosine-3',5'-monophosphate phosphodiesterase in vitro under the influence of neurohormone C]

The work was devoted to one of the new neurohormones (neurohormone "C") obtained from the bovine hypothalamus which produced a pronounced relaxation of the coronary vessels. A study of the effect of "C" on cyclic 3',5'-adenosine monophosphate (cAMP) phosphodiesterase (PDE) showed "C" to be a potent inhibitor of PDE in the crude PDE-preparations of the rat heart and brain. Experiments were carried out on the 2000 g supernatant obtained from the homogenized tissues. It is supposed that the relaxant effect of "C" on the coronary vessels is due to its inhibitory action on PDE mediated by the accumulated cAMP.