[Myocardial cell adenyl cyclase activity and the effect of thyrocalcitonin]

The thyrocalcitonin (TCT) effect under influence of some factors affecting the activity of membrane adenylcyclase (AC) of the ventricle myocardial cells in cold-blooded animals, was studied. The TCT positive inotropic effect is intensified by decrease in the potassium concentration in the medium, by blockade of alpha-adrenoreceptors with phentolamine, and inhibited by increase in the potassium concentration and blockade of beta-adrenoreceptors. The TCT action is preserved in presence of adrenaline.