DDAVP (1-desamino-8-D-arginine-vasopressin) treatment of lithium-induced polyuria in the rat.

The antidiuretic responses of arginine vasopressin (AVP) and 1-desamino-8-D-arginine vasopressin (DDAVP) were studied in rats with marked lithium-polyuria (about 100 ml/100 g/24 h) induced by administration of lithium to the diet for 3-4 months. The hormones were infused i.v. and s.c. at a constant rate for 7 days using implantable osmotic minipumps. Body weight, food consumption and urine volume and osmolality were recorded daily. Whereas supramaximal doses of AVP only had little effect on spontaneous urine flow and osmolality, DDAVP (0.1 microgram/h i.v. or 1 microgram/H s.c.) restored urine volume and osmolality to near-normal values. Although the mechanism of the antidiuresis evoked by DDAVP was not investigated the ability of this compound to reverse AVP-resistant polyuria may be due to its specificity and high intrinsic activity in stimulating the vasopressin receptor. The reversibility of lithium-induced impairment of renal concentrating ability caused by excessive hormonal stimulation is not immediately compatible with the recent hypothesis that lithium-polyuria may reflect irreversible structural kidney damage.