Efficiency of Osmotic Concentration after Combined Treatment with Vasopressin and Blockage of Prostaglandin Synthesis

We performed a complex functional study of the effects of prostaglandin synthesis blockage with diclofenac on manifestation of the hydroosmotic effect of vasopressin V2-receptor agonist desmopressin in the kidneys of Wistar rats with normal synthesis of endogenous vasopressin and homozygous Brattleboro rats with hereditary impaired synthesis of neurohypophyseal hormone vasopressin. Blockage of prostaglandin synthesis led to more pronounced increase in urine osmolality in Brattleboro rats than in Wistar rats due to elevation of not only urine but also sodium gradient at the expense of elimination of the inhibitory effect of prostaglandins on sodium reabsorption and membrane permeability for urine. During combined treatment, the effects of the hormone predominated: the increase in urine osmolality in Wistar and Brattleboro rats did not differ from that after desmopressin administration.