STUDIES ON THE RENAL CONCENTRATING MECHANISM. V. EFFECT OF DIURETIC AGENTS *

Abstract

The effect of osmotic (mannitol, urea, saline), mercurial, ammonium chloride-potentiated mercurial, chlorothiazide, and acetazoleamide diuresis on renal concentrating ability was determined in 6 hydropenic young men. There was no consistent difference between the response of the concentrating mechanism to mannitol, urea, and saline diuresis at low rates of urine flow. A marked decrease in concentrating ability was seen during mercaptomerin diuresis as compared with mannitol diuresis at the same urine flows. Meralluride diuresis was associated with a similar decrease in 2 of 3 subjects studied. When mercaptomerin action was potentiated by prior administration of ammonium chloride, there was greater apparent impairment of concentrating ability than with mercaptomerin alone. This impairment indicates that mercurial diuretic agents act at the renal concentrating site as well as on the proximal tubule. Acetazoleamide was also found to cause a decrease in renal concentrating ability while chlorothiazide had little effect.