Comparative Studies of Urinary Electrolyte Excretion, the Renin-Angiotensin-Aldosterone System and Plasma Dopamine-β-Hydroxylase Activity in Patients with Idiopathic Edema and Normal Subjects during the Menstrual Cycle

Abstract

The changes of circumferential size of legs, urine output, the amount of urinary Na and K excretion, tubular rejection fraction of Na (TRF Na), urinary Na/K ratio, plasma renin activity (PRA), plasma aldosterone concentration (PAC), the amount of urinary aldosterone excretion (UAE) and plasma dopamine-beta-hydroxylase activity (DBH) were studied in 7 patients with idiopathic edema and 5 normal subjects from the recumbent to upright positions by a water loading test (oral ingestion of 1 L of water) in the follicular and luteal phase of the menstrual cycle. The increase in circumferential size of legs in the patients with idiopathic edema was greater than in normal subjects. The percent reduction in urine output, urinary Na excretion, TRF Na and urinary Na/K ratio (upright versus supine) in patients with idiopathic edema tended to be greater than that in normal subjects. However, these indices showed no significant differences between the follicular and luteal phase both in patients with idiopathic edema and normal subjects. PRA and PAC, on the subjects' being tilted to the upright position after water loading, were not significantly different between patients with idiopathic edema and normal subjects during the menstrual cycle, while increases in PAC and UAE were noted in patients with idiopathic edema in the upright position, especially in the follicular phase. Interestingly, plasma DBH activity in patients with idiopathic edema was significantly lower than that in normal subjects in both the follicular and luteal phases. These results indicate that posturally induced anti-diuresis and anti-natriuresis seems not to be related to the phase of the menstrual cycle, and abnormal mechanisms of the dopaminergic autonomic nervous system might exist in this disorder.