[Natriuretic factors].

There appears to be two distinct natriuretic factors. One group, suspected since 1951 in overloaded dogs, had a low molecular weight: it belongs great affinity for ouabain, binds to digoxin antibodies and inhibits NA-K ATPase; this group seems heterogeneous in spite of the extraction of an amino glucosteroid-like substance from human urines. These factors are vasoconstrictor; the source is not still well known (hypothalamus ?). The atrial natriuretic factor (ANF) is a peptide about 20 to 25 amino acids and comes from a precursor of 152 amino acids, its synthesis was successful; secreted in the plasma from endocrine atrial granules, it causes striking natriuresis and diuresis and relaxes vascular and intestinal smooth muscle; it acts on guanylate cyclase but its renal mechanism of action is not well known; it constitutes an antagonist axe to ADH and RAA system. The relations between the two groups of natriuretic factors do not seem still very clear.