RESUMEN
Three groups of women underwent water loading tests: normal subjects, idiopathic oedema patients who had taken no medication for at least 3 months, and a second oedema group with recent diuretic intake. Idiopathic oedema in drug-free patients was characterized by an abnormal capillary permeability, lower basal protein values, a dramatic drop in urinary output in the upright position due to reduced glomerular filtration, enhanced reabsorption of sodium and water and stimulation of aldosterone and antidiuretic hormone (AVP) secretions. In these idiopathic oedema cases, osmolar AVP regulation was disrupted but AVP control by plasma volume was maintained. In the basal state, patients with recent diuretic intake were characterized by a gain in body weight and by depletion of plasma volume and plasma potassium. In these subjects, urinary output in the upright posture was as insufficient as in drug-free patients but was due to higher sodium reabsorption. Renal insensitivity to AVP action was also observed. Osmolar regulation and volume regulation of AVP were both disrupted in these cases with recent diuretic intake.