EFFECTS OF DEOXYCORTICOSTERONE ACETATE AND CORTISONE ON THE EXCRETION OF HYPOTONIC SALINE BY ADRENALECTOMIZED RATS

Abstract

SUMMARY The response to loads of hypotonic saline has been investigated in intact and in adrenalectomized rats treated with deoxycorticosterone acetate, with cortisone acetate and with both steroids. The response of untreated adrenalectomized animals was also studied. Intact rats excreted more water than sodium during the 5 hr after loading with hypotonic saline. There was a reduction of the proportion of water reabsorbed in the renal tubules, but the proportion of sodium reabsorbed was unaltered. Adrenalectomized rats, either with or without deoxycorticosterone treatment, did not show this diuretic response, and there was evidence that sodium was lost from the body cells. Rats in these two groups reabsorbed a smaller proportion of sodium in their renal tubules than intactrats. Adrenalectomized rats treated with cortisone showed partial restoration of the ability to excrete water, but the renal loss of sodium was greater than in intact animals. Treatment of adrenalectomized rats with both cortisone and deoxycorticosterone restored water excretion to normal values, but excessive amounts of sodium were lost. In neither group which received cortisone was there any indication of loss of cell sodium. The response of rats in the group receiving both steroids was not a normal water diuresis because the animals were unable to excrete water without loss of sodium. It appeared unlikely that there was excessive antidiuretic hormone activity in the rats receiving cortisone and that some factor other than reduction of pituitary antidiuretic hormone secretion was essential for normal water diuresis.