Brain-type Natriuretic Peptide (BNP) is a nonglycosylated peptide that is produced predominantly by ventricular myocytes and belongs to the natriuretic peptide family.

Plasma NT-proBNP is a marker for congestive heart failure, while mature BNP (aa 103 - 134) promotes vasodilation and fluid and sodium excretion.BNP is co-secreted along with a 76 amino acid N-terminal fragment (NT-proBNP) which is biologically inactive. BNP binds to and activates the atrial natriuretic factor receptors NPRA, and to a lesser extent NPRB, in a fashion similar to atrial natriuretic peptide (ANP) but with 10-fold lower affinity. The biological half-life of BNP, however, is twice as long as that of ANP, and that of NT-proBNP is even longer, making these peptides better targets than ANP for diagnostic blood testing.