Atrial natriuretic factor--a new hormone affecting kidney function.

A family of biologically active peptides (atrial natriuretic factor - ANF) has recently been identified in mammalian heart atria. The peptides derive from a common 152 amino acid precursor and at least 1% of total messenger RNA activity is specific for the factor. When injected intravenously ANF is hypotensive and natriuretic. Data indicate that atrial natriuretic factor represents a newly discovered hormone involved in the regulation of blood pressure and volume. Cellular release of ANF does not require the activation of the adenylate cyclase system, but is associated with receptor-mediated activation of the cellular polyphosphoinositide mechanism. The natriuretic effect includes increased glomerular filtration rate and specific inhibition of normal sodium reabsorption from the medullary collecting duct. The mechanism of this transport inhibition is not yet known.