α‐HUMAN ATRIAL NATRIURETIC POLYPEPTIDE REDUCES THE PLASMA ARGININE VASOPRESSIN CONCENTRATION IN HUMAN SUBJECTS

The synthetic alpha-human atrial natriuretic polypeptide (alpha-hANP) was infused into six normotensive, euvolaemic, healthy volunteers to examine the effect on the plasma arginine vasopressin (AVP) concentration. The intravenous administration of alpha-hANP (0.1 microgram/kg/min, 20 min) led to a remarkable reduction in mean blood pressure (-10 mmHg, P less than 0.05), and there was an increase in pulse rate (+10 bpm, P less than 0.05), in each subject. The urinary volume, sodium excretion and cyclic 3',5'-guanosine monophosphate (cyclic-GMP) excretion were increased to 3.5 (P less than 0.05), 2.5 (P less than 0.05) eight-fold (P less than 0.01), respectively, during the alpha-hANP infusion. The dose and duration of the synthetic alpha-hANP in the present study was sufficient to induce these cardiovascular and renal effects. The plasma AVP concentrations decreased from 0.39 +/- 0.09 pg/ml to the undetectable level during the alpha-hANP administration. After infusion, the plasma concentrations of the AVP promptly returned to preinfusion levels (0.46 +/- 0.14 pg/ml). However, there was no significant change in plasma AVP concentration during placebo infusion. The marked suppression in plasma AVP concentration may account for the remarkable diuresis, in addition of the direct renal effects of the synthetic alpha-hANP.