Effects of bromocriptine on renin, aldosterone, and prolactin responses to posture and metoclopramide in idiopathic edema: possible therapeutic approach.

This study examines the effect of bromocriptine therapy (2.5 mg three times daily for 4-5 days) on orthostatic increases in weight, PRA, plasma aldosterone, and PRL in patients with idiopathic edema and in normal female controls. Additionally, PRA, aldosterone, and PRL responses to the dopamine antagonist metoclopramide were examined in both groups before and after bromocriptine. Edema patients demonstrated greater orthostatic weight gain and greater aldosterone and PRL responses to upright posture and isometric handgrip exercise. However, after bromocriptine treatment, these orthostatic responses were similar to those noted in normal controls. After metoclopramide administration, edema patients displayed normal PRA and aldosterone responses, but had exaggerated PRL responses. After bromocriptine, the PRL, but not the PRA or aldosterone, response to metoclopramide was greatly reduced. The PRL responses to metoclopramide were similar in edema patients and controls after bromocriptine treatment. These data suggest that there is decreased dopaminergic inhibition of aldosterone and PRL in response to upright posture in the idiopathic edema syndrome. Diminished orthostatic urinary excretion of sodium appears to be related to decreased dopaminergic tone in this syndrome. These abnormalities are largely corrected by tolerable doses of the dopamine agonist bromocriptine.