Arginine vasopressin dissociates the diuresis and natriuresis due to atrial natriuretic factor in man

The possible interaction between arginine vasopressin (AVP) and atrial natriuretic factor (ANF) in the control of urinary sodium and water excretion was investigated in man. Nine healthy male volunteers undergoing stable maximal water diuresis were studied on four separate occasions. Atrial natriuretic factor 15 pmol kg-1 min-1 or placebo (P) was concomitantly administered against a background infusion of either AVP 0.003 pmol kg-1 min-1 or P; thus the combinations P + P, AVP + P, P + ANF and AVP + ANF were studied. Atrial natriuretic factor caused a significant increase in sodium excretion (UNaV) [+56%], urinary flow rate (V) [+17%] and free water clearance (CH2O) [+23%]; creatinine clearance (Ccr) did not change. Arginine vasopressin reduced V (-58%) and CH2O (-68%) but did not alter UNaV or Ccr. On the AVP + ANF study day, UNaV increased (+64%) as with P + ANF, but V (-44%) and CH2O (-52%) continued to decrease below baseline levels; analysis of variance showed this antidiuresis reflected the prevalent effect of AVP rather than any specific interaction. These results show that AVP is able to dissociate the natriuretic and diuretic effects of ANF.