Dissociation of antipolyuric action and increase in plasma renin activity caused by chlorothiazide in Brattleboro rats.

The previous finding that chlorothiazide (about 250 mg/day) induces a sustained reduction in the polyuria of homozygous Brattleboro (BB) female rats, as well as an increase to about 250% of plasma renin activity was confirmed. Disruption of the renin-angiotensin system by either the angiotensin antagonist saralasin or the beta-blocking agent propranolol does not interfere with chlorothiazide antidiuresis. Each inhibitor reduces BB polyuria on its own, an effect which, however, may be explained by a possible interference with thirst.