[The evidence for the existence of an endogenous factor with digitalis activity in mammals: a physiological regulator of the sodium pump?].

In the last years a great deal of reports on the presence of endogenous digitalis-like activity in mammals have appeared in the literature. The active factor could be an endogenous ligand of the digitalis receptor and thus a physiological humoral regulator of sodium pump activity. Such an agent would necessary have a whole series of physiological and physiopathological implications. It has been proposed that the factor is a natriuretic hormone, that it participates in blood pressure regulation and in the genesis of arterial hypertension, that it plays a role in pregnancy and that it regulates cardiac contractility. These hypotheses are discussed in the present review.