Natriuretic peptide system and the heart.

The natriuretic peptide (NP) family includes atrial (ANP), brain or B-type (BNP) and C-type NP (CNP). A huge number of experimental and clinical studies, published in the 1st decade of this century, have added further support to the hypothesis that endocrine function in the human heart is a relevant component of a complex network including endocrine, nervous and immune systems. The NP hormones constitute a well-integrated regulatory system and share a similar spectrum of biological actions, although there are some differences in biological potency between ANP, BNP and CNP. However, several important issues on this field need to be investigated further. The production, secretion and peripheral degradation pathways of both BNP and CNP should be clarified in detail. In particular, the hypothesis that the circulating plasma pool of the prohormone can function as a precursor of the active peptide hormone should be demonstrated definitively. Recent findings indicate that peripheral processing of circulating prohormones could likely be submitted to regulatory rules, which might be impaired in patients with heart failure, opening up new perspectives even in the treatment of heart failure. This hypothesis suggests a novel pharmacological target for drugs inducing and/or modulating the maturation of the prohormone into active hormone.