Effect of renal papillectomy on ability of the hamster to concentrate urine

¹ Department of Pharmacology, State University of New York Upstate Medical Center, Syracuse, New York

The effect of surgical removal of the distal portion of the renal papilla was evaluated by subjecting three groups of animals— 1) bilateral papillectomy, 2) unilateral papillectomy with nephrectomy; 3) normal controls—to regimens producing hydration and dehydration. Bilateral sham operations caused no significant effect. The animals were placed in metabolism cages and given carrots alone (hydrating diet), pellets alone (dehydrating diet), and pellets and water ad libitum (normal diet). There were no differences in urine osmolality on carrots alone. During progressive dehydration, the more marked the dehydration the greater the difference in urine osmolality between control and papillectomized animals. On the normal diet, the papillectomized animals consistently excreted twice the volume of a more dilute urine than the controls. Water loads were excreted more rapidly by the papillectomized groups. Simultaneous administration of a 6% oral water load and 100 mU of vasopressin intramuscularly showed that papillectomy reduces the response to an antidiuretic hormone. The results are consistent with the countercurrent hypothesis.