Abstract: Brain natriuretic peptide (BNP) is a 26 amino acid peptide which not only shows a high sequence homology to atrial natriuretic peptide (ANP), but also has very similar pharmacological effects to that of ANP. It have also been found that BNP interacts with ANP receptor. We consider that the secretions of BNP and ANP must interrelate and interact with each other. Based on that fact, we conducted the present study. Our results show that the infusion of BNP (40ug/kg) for 60 minutes leads to an increase of both ANP level in plasma and ANP content in atria, In vitro BNP (10mol/L) perfusion cannot stimulate the atrium to secrete ANP. We consider that the increase of both ANP level in plasma and ANP content in atriums is a result of an increase of synthesis and secretion of ANP in atria, but it is not a direct effect of BNP on atria. We infer that because of the binding of BNP to ANP receptor, there is a decrease in quantity of ANP receptors and it leads to a compensatory increase of ANP. We also found that NPY plasma concentration increased foolowing the infusion of BNP. We consider that it is a result of conpensation to weaken the vasodilatory effect of BNP on arteries.

Key words: brain natriuretic peptide, atrial natriuretic peptide, neuropeptide Y, ANP secretion