RESUMO
Antidiuretic action of oxytocin is confirmed by in vitro study using with rat IMCD. Vasopressin is elevated in edematous disorders and may play a pathogenetic role in the formation of edema. If oxytocin plays a sirnilar role to vasopressin in water disturbances in human, oxytocin may change as the same way as vasopressin. To verify a role of oxytocin in the regulation of water balance in human, we measured plasma and urine oxytocin with vasopressin by radioimmunoassay in thirteen patients with generalized edema (8 nephrotic syndrome, 3 liver cirrhosis, 2 acute renal failure) before and after control of edema. And they were compared them with those of seven normal controls. Plasma oxytocin level correlated with plasma vasopressin level (r=0.543: P<0.05) and urinary oxytocin level correlated linearly with urinary vaso-pressin (r=0.983, P<0.01). After control of edema, body weight of patients decreased from 65+/- 2 to 58+/-2kg and fractional excretion of sodium decreased from 3.3+/-1.1 to 1.2+/-0.696 (P<0.05). There were no significant changes in serum and urine Na, osmolality, free water clearance, plasma renin activity, aldosterone and norepinephrine. In conclusion, oxytocin was elevated in edematous disorders, and may participate in formation of edema similar to vasopressin.