N-Terminal Pro-Atrial Natriuretic Peptide (NT-ProANP)

ANP is a hormone important in maintaining body fluid and sodium homeostasis. In cardiomyocytes, human ANP is synthesized as a 151-amino acid prepropeptide. After the signal peptide is removed by the signal peptidase, pro-ANP is stored in the dense granules of the cell. On stimulation, pro-ANP is released from the dense granules and activated on the cell surface by proteolytic cleavage at residue arginine 98, generating an NH2-terminal propeptide and a 26-amino acid COOH-terminal peptide that is biologically active. Plasma concentration of N-terminal atrial natriuretic peptide (Nt-proANP) is strongly directly related to salt sensitivity.In contrast to Nt-proANP, Nt-proBNP is not related to salt sensitivity. Salt sensitivity, as estimated by Nt-proANP, seems to be reduced in type 2 diabetes. Both N-ANP and N-BNP identifies a greater number of patients at risk of death or heart failure than either peptide alone.