Brain natriuretic peptide

Brain natriuretic peptide (BNP), also known as B-type natriuretic peptide, is a hormone secreted by the heart and blood vessels that helps regulate blood pressure and fluid balance. It is primarily produced by the ventricles of the heart in response to excessive stretching of heart muscle cells (cardiomyocytes).

Function

BNP is part of the natriuretic peptide system, which includes three types of peptides: atrial natriuretic peptide (ANP), BNP, and C-type natriuretic peptide (CNP). These peptides are involved in the regulation of extracellular fluid volume and blood pressure.

BNP is released in response to changes in pressure inside the heart. These changes can occur with heart failure and other conditions that increase the workload of the heart. BNP has several actions that help to reduce the increased workload and prevent further damage to the heart. These include:

• Dilating the blood vessels. This can lower blood pressure and decrease the amount of work the heart has to do to pump blood.
• Increasing the excretion of sodium and water by the kidneys. This can help to reduce blood volume and decrease the workload on the heart.
• Inhibiting the release of renin and aldosterone, two hormones that can increase blood pressure and fluid volume.

Clinical significance

Measurement of BNP or its inactive N-terminal fragment (NT-proBNP) in blood can be used as a diagnostic and prognostic tool in heart failure. Elevated levels of BNP or NT-proBNP in the blood are indicative of heart failure and can be used to differentiate heart failure from other conditions with similar symptoms, such as lung disease.

In addition to its role in diagnosing heart failure, BNP measurement can also be used to assess the severity of heart failure and to monitor response to treatment. It is also being studied for its potential role in predicting outcomes in various other conditions, including kidney disease, critical illness, and sepsis.

See also

• Natriuretic peptide
• Heart failure
• Blood pressure
• Hormone