Disparity Between Fluid Intake and Renal Concentrating Deficit in Dogs With Diabetes Insipidus

Abstract

Dogs with striking diabetes insipidus precipitated by a "hypothalamic puncture" procedure possess considerable residual renal concentrating ability which increases measurably with postoperative time. The question arises as to whether this concentrating ability is due to or is independent of endocrine antidiuretic activity. Pitressin admn. uniformly restored renal concentrating ability to normal even during the stress of osmotic loading. The renal concentrating deficit was not quantitatively sufficient to account for the extremely high rates of water exchange in the dogs observed. It therefore seems apparent that the enhanced thirst in diabetes insipidus is not caused solely by the threat of dehydration resulting from the renal concentrating deficit.