Brain natriuretic peptide
(BNP), now known as B-type natriuretic peptide
(also BNP) or GC-B
, is a 32 amino acid polypeptide secreted by the ventricles
of the heart
in response to excessive stretching of heart muscle cells (cardiomyocytes). BNP is named as such because it was originally identified in extracts of porcine
brain, although in humans it is produced mainly in the cardiac ventricles.
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.
The physiologic actions of BNP are similar to ANP and include decrease in systemic vascular resistance
and central venous pressure as well as an increase in natriuresis
. Thus, the net effect of BNP and ANP is a decrease in blood volume and a decrease in cardiac output.
Both BNP and NT-proBNP levels in the blood are used for screening, diagnosis of acute congestive heart failure
(CHF) and may be useful to establish prognosis in heart failure, as both markers are typically higher in patients with worse outcome. The plasma... Read More