Osmotic (Mannitol) Diuresis in the Anesthetized Rat Effectiveness of Water Conserving Mechanisms

¹ From the Division of Research, The Cleveland Clinic Foundation, and The Frank E. Bunts Educational Institute, Cleveland, Ohio

During mannitol osmotic diuresis, the rat shows a dependence of urine flow on solute load and a rough proportion between solute load and electrolyte output. In terms of body weight, the rat's renal ability for water conservation during osmotic diuresis is to that of dog and man, respectively, as 6 is to 2.5 and to 1; this ability to conserve water may be a factor in the survival capacity of this species. Mercurial diuresis in the rat, as in other species, is apparently an osmotic diuresis. The procedure permits partial characterization of the mechanisms of action of test materials with renal and urinary effects.