IMPAIRED WATER-EXCRETION IN PANHYPOPITUITARISM WITH ANTIDIURETIC-HORMONE DEFICIENCY

Background: Experimental and human studies point to a critical role fo r elevated AVP levels in the delayed water excretion observed in adren al and thyroid insufficiencies. Very few studies have been devoted to this phenomenon in hypopituitarism. Objective: To evaluate impaired wa ter excretion of hypopituitarism in patients with arginine-vasopressin (AVP) deficiency. Design: Prospective study using the water load test . Setting: Service d'Endocrinologie, Centre Pierre et Marie Curie, Alg iers. Subjects: Twenty patients with post-partum hypopituitarism (Shee han's syndrome) with confirmed anterior pituitary insufficiency and AV P secretion failure. The water load test is performed on the same pati ents before treatment, after cortisol substitution and after cortisol and thyroid hormone treatment, Twelve normal women serve as controls. Main measures: Urinary volume, plasma and urinary osmolality, urinary AVP excretion. Results: AVP excretion is similarly suppressed in contr ols and patients whether treated or not. Impairment in water excretion is clearly observed in the untreated patients. Dilutional ability is increased after hydrocortisone and not modified further by thyroxine. Conclusion: Excess of AVP is not a prerequisite factor in delayed wate r excretion since the impairment is observed in AVP-deficient patients . These results are rather in favor of a pre-eminent role of AVP-indep endent renal hemodynamic.