[The characteristics of the effect of parathyroid hormone on the mechanical activity of the myocardium in rats with a deficiency of Ca and Mg in the drinking water].

Inotropic and lusitropic effects of the parathyroid hormone (PTH) upon the rat heart ventricle myocardium were studied in conditions of calcium and magnesium deficit in drinking water. The control rats revealed two phases of the hormone effect: the positive and negative ones, whereas the experimental rats only revealed the negative inotropic effect. Both the negative and positive inotropic effects were followed by an acceleration of the relaxation.