Effects of Deoxycorticosterone Acetate in Unilaterally Nephrectomized Dogs with Renal Artery Constriction

Abstract

The response to the chronic daily administration of 25 mg/day of deoxycortico-costerone acetate (DCA) was studied before and following renal artery constriction in unilaterally nephrectomized dogs. Both before and after constriction of the renal artery there was an initial period of Na retention which lasted 1-5 days but all animals escaped from the Na-retaining action of DCA. Glomerular filtration rate (GFR) and renal plasma flow (RPF) as measured in the post-absorptive state were reduced in 7 of the 8 dogs with renal artery constriction, and a subsequent rise in renal function was not detected during DCA injection. Also, the normal postprandial rise in GFR failed to occur during DCA administration to dogs with renal artery constriction. Fractional urine collections revealed a normal pattern of renal Na excretion during DCA administration to dogs with renal artery stenosis in that most of the Na ingested with the meal was excreted during the postprandial period. The present data demonstrate, therefore, that reduced GFR and RPF and other renal hemodynamic alterations secondary to renal artery constriction failed to block the renal "escape" from DCA. By exclusion, the available evidence suggests the possibility that a humoral agent provokes the unusual responsiveness of the renal tubules to DCA in experimental animals and in certain patients who show this phenomenon.