Reposital vasopressin response test in clinically normal dogs undergoing water diuresis: technique and results

Maximal renal concentrating ability after parenteral administration of repositol antidiuretic hormone was evaluated in 13 clinically normal dogs undergoing water diuresis. Urine specific gravity and osmolarity progressively increased in all dogs and generally attained maximum concentrations after 8 to 12 hours. Urine specific gravity values increased from mean of 1.003 +/- 0.001 mOsm/kg of water to a mean maximal value of 1.042 +/- 0.009 mOsm/kg. Urine osmolarity increased from a mean of 132 mOsm/kg to a mean maximal value of 1,518 +/- 242 mOsm/kg. Water intoxication was observed in all dogs due to continued administration of water after antidiuretic hormone administration.