ARGININE VASOPRESSIN INFUSION INCREASES PLASMA-LEVELS OF ATRIAL-NATRIURETIC-FACTOR IN HUMANS

Seven normal subjects underwent sequential 20-min infusion of arginine vasopressin (AVP) at 0.5 and 2 ng/(kg.min) and a complete right-side heart hemodynamic evaluation during the study to analyze the effect of this hormone on atrial natriuretic factor (ANF) secretion in humans a nd to elucidate whether this effect was primary or secondary to the he modynamic or hormonal changes induced by AVP. Plasma ANF levels increa sed at the end of the first (P < 0.05) and second (P < 0.01) infusion periods. No significant changes in mean arterial, pulmonary artery, ri ght and left atrial pressures were recorded during the study. Cardiac output (P < 0.05) and heart rate (P < 0.05) decreased, while total vas cular resistances (P < 0.05) increased with respect to basal values in both infusion periods. Plasma renin activity decreased (P < 0.01) at the end of the infusion, while plasma aldosterone, epinephrine and nor epinephrine showed no significant changes. We conclude that arginine v asopressin increases plasma ANF levels in humans and that this effect cannot be ascribed to hemodynamic or hormonal changes induced by this hormone, suggesting a direct effect of vasopressin on the atrial myocy te.