Differential responses of plasma atrial and brain natriuretic peptides to acute alteration in atrial pressure in pigs

Abstract

To describe the differential dynamic responses of atrial natriuretic peptide (ANP), N-terminal proatrial natriuretic peptide (Nt-proANP) and brain natriuretic peptide (BNP) to acute changes in atrial pressure, 6 pigs were studied during and after a 24-h period of rapid atrial pacing (225 bpm). During pacing, left atrial pressure increased acutely. ANP plasma concentrations showed a sharp initial peak followed by a decline, but remained significantly increased throughout the 24-h period. Nt-proANP followed a smoother pattern, increasing significantly only after 24 h. BNP increased significantly after 8 h after pacing and even more after 24 h. An opposite but similarly differential pattern of peptide responses was found in the post-pacing period. The different responses in ANP, Nt-proANP and BNP plasma concentrations may reflect the different mechanisms of regulation of secretion as well as plasma clearance. If the present findings reflect the acute clinical situation in humans, they may be of diagnostic relevance. An isolated ANP elevation would indicate a recent acute pressure increase, while elevation of two or more natriuretic peptides would point to a pressure increase of longer duration.