Cardiac hormone that plays a key role in mediating cardio-renal homeostasis (By similarity). May also function as a paracrine antifibrotic factor in the heart (By similarity). Acts by specifically binding and stimulating NPR1 to produce cGMP, which in turn activates effector proteins that drive various biological responses. Involved in regulating the extracellular fluid volume and maintaining the fluid-electrolyte balance through natriuresis, diuresis, vasorelaxation, and inhibition of renin and aldosterone secretion. Binds the clearance receptor NPR3 (By similarity). Detected in blood. The precursor molecule is proteolytically cleaved, possibly by FURIN or CORIN, to produce the active peptide (By similarity). May undergo further proteolytic cleavage by various proteases such as DPP4, MME and possibly FAP, to give rise to a variety of shorter peptides (By similarity). May be cleaved at Ser-102 by the prolyl endopeptidase FAP (seprase) activity (in vitro) (By similarity). May be degraded by IDE (By similarity). During IDE degradation, the resulting products initially increase the activation of NPR1 and can also stimulate NPR2 to produce cGMP before the fragments are completely degraded and inactivated by IDE (in vitro) (By similarity). Belongs to the natriuretic peptide family.