[Endogenous compounds of the digitalis type in essential and arterial hypertension]

Endogenous digitalis-like compounds are present in biological fluids and in some tissues. Little is known, so far, about their chemical nature and the tissues where they originate. Plasma and urinary levels of these compounds are elevated in essential and experimental arterial hypertension, and this rise may contribute to the genesis and maintenance of an abnormally high blood pressure. This is explained by an increase in intracellular calcium concentration resulting from inhibition of the sodium/potassium pump and increase of intracellular sodium. Concerning the chemical nature of these endogenous digitalis-like compounds two hypotheses have been put forward: peptides or steroids. Precise identification of these compounds and a knowledge of their mechanism of action on the sodium/potassium pump will probably lead to the development of new drugs in the field of cardiovascular and renal diseases.