Cardiac-derived
peptide hormones were identified more than 25 years ago. An astonishing amount of clinical studies have established cardiac
natriuretic peptides and their molecular precursors as useful markers of
heart disease. In contrast to the clinical applications, the biogenesis of cardiac
peptides has only been elucidated during the last decade. The cellular synthesis including
amino acid modifications and proteolytic cleavages has proven considerably more complex than initially perceived. Consequently, the elimination phase of the
peptide products in circulation is not yet well characterized. An ongoing characterization of the molecular heterogeneity will help appreciate the biosynthetic capacity of the endocrine heart and could introduce new diagnostic possibilities. Notably, different biosynthetic products may not be equal markers of the same pathophysiological processes. An inefficient post-translational prohormone maturation will also affect the biology of the cardiac
natriuretic peptide system. This review aims at summarizing the myocardial synthesis of
natriuretic peptides focusing on
B-type natriuretic peptide, where new data has disclosed cardiac myocytes as highly competent endocrine cells. The structurally related
atrial natriuretic peptide will be mentioned where appropriate, whereas
C-type natriuretic peptide will not be considered as a cardiac
peptide of relevance in mammalian physiology.