Atriopeptins as cardiac hormones.

NUMEROUS observations have implicated humoral factors in the homeostatic regulation of fluid and electrolyte balance. This review will focus on a recently discovered peptide that is synthesized and stored in cardiac atrial myocytes and exerts potent, selective, and transient biological effects. Characterization of the cardiac substance has shown that it is not related to endogenous Na,K-ATPase inhibitors, which may also act as natriuretic hormones. The atrial peptide is a potential hormonal mediator of changes in body fluid composition, extracellular volume, and systemic blood pressure. An earlier review describing the initial isolation and chemical and biological characterization of the atrial peptides has been published (see ref. 2).