Effect of Desoxycorticosterone on Distribution of Water and on Electrolyte Excretion During Enforced Hydration in the Dog and Rat

Abstract

Enforced hydration was produced in dogs and rats by simultaneous administration of Pitressin and of water loads totaling 15% or more of body weight in the dogs and 19% in the rats. The effect of desoxycorticosterone on the distribution of the added water was determined in the dogs by means of bromide and antipyrine spaces and chloride balance. In both species the modifying effect of DCA on the natriuresis and chloruresis of enforced hydration was studied. In the normal dog, the retained water load was distributed evenly throughout total body water. Addition of DCA to the water loading and Pitressin regimen resulted in a disproportionate expansion of the chloride space and in the production of edema. In the dog, DCA appears to exert a direct effect on the distribution of a water load which can be demonstrated in the absence of electrolyte retention. Edema was not noted with DCA administration to rats subjected to the water loading-Pitressin regimen, suggesting a species difference with respect to this action of the hormone. In both the dog and rat, the natriuresis and chloruresis associated with overexpansion of body fluid volume produced by water loading was neither inhibited nor enhanced by the administration of DCA. In certain of the dogs receiving DCA, the timing of the natriuretic and chloruretic response differed from that seen in normal animals but the deviations were neither consistent nor reproducible.