Endogenous peptide secreted from cardiac ventricles in response to volume increase and pressure overload that acts as an agonist at atrial natriuretic peptide (ANP) receptor A (NRP1). Decreases de novo collagen synthesis and increases MMP gene expression in vitro. Exhibits natriuretic, vasodilatory and lusitropic activity and inhibits the sympathetic and renin-angiotensin-aldosterone systems in vivo.