The Characteristics of Renal Hypoperfusion in Dogs with Acute and Chronic Reductions in Glomerular Filtration Rate as Disclosed by the Pattern of Water and Solute Excretion after Hypotonic Saline Infusions *

Under ordinary circumstances the elaboration of a dilute urine is dependent upon suppression of the secretion of antidiuretic hormone (ADH). Even when ADH secretion is maximally sup- pressed, however, a concentrated urine may be formed. Berliner and Davidson (1), del Greco and de Wardener (2), and Kleeman, Maxwell, and Rockney (3) have demonstrated that a reduction in glomerular filtrationi rate (GFR) can result in the excretion of hypertonic urine in the absence of ADH activity.