Molecular biology of the natriuretic peptide system: implications for physiology and hypertension

The natriuretic peptides (NPs) are a group of peptide hormones that play important roles in the control of renal, cardiovascular, endocrine, and skeletal homeostasis. Atrial NP (ANP) was first identified as an activity by de Bold et al1 in 1981. It is a 28 amino acid peptide in humans that assumes a hairpin structure by virtue of a cystine bridge that links residues 7 and 23 (Figure 1). Brain NP (BNP), also known as the B-type NP, is 32 amino acids long in the human. It has a similar hairpin structure but demonstrates considerably more heterogeneity across species than ANP. C-type NP (CNP) is a 22 amino acid peptide that has a truncated carboxy terminus beyond the second cystine residue in the bridge.