atrial natriuretic peptide (ANP)
Atrial natriuretic peptide (ANP), also known as atrial natriuretic factor (ANF) or atriopeptin, is a 28-amino acid polypeptide hormone which is involved in the homeostatic control of body water, sodium, and adiposity. Atrial natriuretic peptide (ANP) is released by atrial myocytes – cells in the atria of the heart – in response to signals of raised blood pressure and acts to reduce the water, sodium, and adipose loads on the circulatory system, thereby returning blood pressure to more normal levels.
Elevated levels of ANP are found during hypervolemic states (elevated blood volume) and congestive heart failure. Children with congenital heart disorders causing heart failure have high levels of ANP. These levels fall after successful surgery to correct the abnormality.
A second natriuretic peptide, called brain-type natriuretic peptide (BNP), is a 32-amino acid peptide that is synthesized within the ventricles (as well as in the brain where it was first identified).