Peptides of natriuretic-diuretic activity have been identified and implicated in the control of extracellular fluid volume and electrolyte homeostasis. There are multiple forms of these so-called atrial natriuretic polypeptides (ANP), ranging in molecular weight from 3,000 to 13,000, and it has been suggested that all may derive from the same precursor.

The cDNA of the natriuretic peptide precursor A gene encodes gamma-ANP, a polypeptide of 13,000 MW, whose C-terminal 28 amino acids are processed as alpha-ANP. Atrial natriuretic factor (ANF) appears to be synthesized as a large precursor, atrial pronatriodilatin. The cDNA has an open reading frame potentially encoding a protein of 152 amino acids, of which the first 24 amino acids strongly resemble a signal sequence. This is followed by a sequence with 80% homology to a second vasoactive protein, porcine cardiodilatin.