saralasin and Polyuria

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.

Topics: Animals; Chlorothiazide; Creatinine; Diabetes Insipidus; Drinking; Drug Interactions; Eating; Female; Osmolar Concentration; Polyuria; Propranolol; Rats; Renin; Saralasin

Acute renal artery stenosis in hydropenic dogs caused a contralateral increase in urine volume and free water clearance without change in glomerular filtration, renal blood flow, or osmolar clearance. The increase in urine volume was not dependent on the development of hypertension since it occurred in animals pretreated with trimethaphan but was dependent upon angiotensin since it was presented with angiotensin blockade with Saralasin. The effect was not caused by angiotensin inhibiting antidiuretic hormone release since the polyuria occurred in hypophysectomized animals receiving a constant infusion of 10 muU/kg per min of aqueous Pitressin. Since the rise in urine volume was associated with an increase in renal vein prostaglandin E concentration and was prevented by pretreatment with indomethacin (5 mg/kg) the results suggest that the rise in plasma angiotensin after renal artery stenosis causes an increase in contralateral prostaglandin E synthesis with resultant antagonism to antidiuretic hormone at the collecting tubule.

Topics: Animals; Blood Pressure; Dogs; Glomerular Filtration Rate; Indomethacin; Polyuria; Prostaglandins E; Renal Artery Obstruction; Renin; Saralasin; Sodium; Trimethaphan; Vasopressins