Determination and Occurrence of Free and Conjugated Histamine in Urine of Sheep

1. By modifying the method of Duriér & Pernow (1956) the urinary excretion of free and conjugated histamine was examined in 11 healthy adult sheep.
2. The mean excretion of free histamine was 9.8 ± 9.0 (s) µg base/24 hrs. (uncorrected for losses during extraction). When individual means were used, the range was: 2.1–34.2 µg base/24 hrs. The intraindividual variations were of the same order as the interindividual variations.
3. The mean excretion of conjugated histamine was equivalent to 15.1 ± 9.9 (s) µg histamine base/24 hrs. In all animals the ratio conjugated/free histamine was above 1. The interindividual as well as the intraindividual variation for conjugated histamine was of the same order as for free histamine.