Acute cardiac volume load-related changes in plasma atrial natriuretic peptide and N-terminal pro-B-type natriuretic peptide concentrations in healthy dogs

Plasma atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) have been used for the diagnosis of heart disease. The aim of the study was to investigate differences in secretory responses of plasma ANP and N-terminal proBNP (NT-proBNP) concentrations related to acute changes in preload. Six dogs were anaesthetised and infused intravenously with Ringer’s solution (90–100 mL/kg/h) for 60 min. Thereafter, furosemide was administered and dogs were monitored for 60 min. Plasma ANP and NT-proBNP concentrations were determined by chemiluminescence enzyme immunoassay and enzyme immunoassay, respectively. Volume overload significantly increased plasma ANP and NT-proBNP concentrations (P < 0.001); however, preload reduction significantly reduced plasma ANP concentrations (P < 0.05) without concurrent changes in plasma NT-proBNP. Mean pulmonary capillary wedge pressures were strongly correlated with plasma ANP concentrations (r = 0.53, P < 0.001), but not plasma NT-proBNP. Thus, plasma ANP is a useful, non-invasive parameter for measuring rapid haemodynamic changes.