[Lithium and water metabolism]

Interaction between lithium+ and water balance was studied in nine patients suffering manic-depressive trouble. Nephrogenic diabetes insipidus with polyuria and polydipsia was induced by Li+ in one case only. No trouble was apparent in eight cases. However, the applied method of investigation by lacking, and next, excess of water, vasopressin and ADH tests, measurements of urinary osmolarity and clearances, showed up a trouble of concentration in four cases, improved by ADH. The Li+ frequently (50%) induces a trouble of urinary concentration, without polyuria; it is brought to light only by biological investigations. Its origin is double, nephrogenic, which is the most important, and central by a pituitary component. In the other hand, the change in water metabolism, studied by the same tests, showed us a decrease of the clearance Li+ after lacking of water (deshydratation), and an increase after water surcharge. That result is not concordant, chiefly in regards to the water surcharge, with former experiments. It appears that our method (division by horary periods for measurement of clearance, study of circadian cycle of urinary Li+) permits some observations more precise than global gathering and measurement of clearances. That method also allows to make evident a circadian cycle of renal clearance of Li+, according to, for some part, with the renal movement of water. That remark would also have some consequence on lithium-therapy practice.