BNP (B-type Natriuretic Peptide)

B-type natriuretic peptide (BNP, also called brain natriuretic peptide based on initial identification site) is a 32-amino acid cardiac hormone secreted primarily by ventricular cardiomyocytes in response to wall stretch and volume overload. It serves as both a physiological regulator of cardiovascular homeostasis and a clinically valuable biomarker for heart failure.

BNP acts through natriuretic peptide receptor A (NPR-A), a guanylyl cyclase-coupled receptor that increases intracellular cGMP. This signaling cascade produces vasodilation, natriuresis, diuresis, and inhibition of the renin-angiotensin-aldosterone system - effects that counteract the fluid retention and vasoconstriction characteristic of heart failure.

Clinically, BNP and its inactive N-terminal fragment (NT-proBNP) are established biomarkers for heart failure diagnosis, risk stratification, and management. Elevated levels indicate cardiac wall stress and correlate with heart failure severity and prognosis. Point-of-care BNP testing enables rapid differentiation of cardiac from pulmonary causes of dyspnea.

Research applications include studying heart failure pathophysiology, investigating natriuretic peptide receptor signaling, developing improved cardiac biomarkers, and understanding the interplay between cardiac and renal function in cardiorenal syndrome. BNP levels also provide insight into cardiac effects of various therapeutic interventions.