Biological half-life and organ distribution of [3H]1-deamino-8-D-arginine-vasopressin in the rat.

The biological half-life of synthetic, radiochemically pure, biologically active [3H]1-deamino-8-D-arginine-vasopressin (dDAVP) in rats was found to be 5.33 +/- 0.28 (S.E.M.) min in the initial, transitional, fast phase and 56.28 +/- 3.27 min in the second, slow phase. The substance accumulated to the greatest extent in the kidney and small intestine and only slightly in the adenohypophysis. The results have suggested that the extended biological half-life may play a role in the more marked and longer antidiuretic effect of dDAVP. The explanation of the poor accumulation in the adenohypophysis may be that dDAVP does not possess an effect similar to that of corticotrophin releasing factor.