The effect of small amounts of antidiuretic hormone on sodium and urate excretion in pregnancy

Abstract

The effect of the infusion of small doses of vasopressin (0.27 to 0.76 milliunit per minute per 1.73 square meters) was studied during water diuresis in 4 healthy nonpregnant women and in 4 healthy subjects in the second and 4 in the third trimesters of pregnancy. During vasopressin infusion the expected marked decrease in urine flow and free water clearance occurred in all subjects. During vasopressin infusion UNaV was unchanged in nonpregnant subjects; it increased slightly in the third trimester; in the second trimester a large increase in UNaV occurred, viz., from 97 μEq per minute to 165 μEq per minute. This increase in UNaV occurred despite a small fall in creatinine clearance. These data indicate that ADH infusion causes both water retention and sodium excretion in the second trimester of pregnancy. Urate excretion was also studied UUrateV increased slightly during vasopressin infusion and, incidentally, in all 12 subjects a highly significant correlation was noted between UNaV and UUrateV.