METABOLISM OF 14C-HISTAMINE IN DOMESTIC ANIMALS

It has been suggested that increased in vivo formation of histamine might he of importance in the pathogenesis of some diseases in ruminants. However, little is known about the degradation of i.v. injected histamine in these species. In the present study isotope dilution technique and paper chromatography were used to examine urinary 14C‐metabolites subsequent to i.v. injection of 14C‐histamine to the goat. During the first week after administration, 80–90 per cent of the activity was found in urine, and about 1 per cent in feces. Known metabolites accounted for 91 –108 per cent of the urinary radioactivity. Oxidative deamination of histamine to imidazoleacetic acid and its riboside seemed to be the only pathway of quantitative importance for histamine degradation in the goat. Paper chromatography revealed that histaminol (4(5)‐imidazolyl‐ethane‐2‐ol) is a metabolite of histamine in the goat accounting for about 2 %of the urinary radioactivity. 14C‐histaminol is formed when liver or kidney homogenates are incubated with 14C‐histamine. © 1969 Scandinavian Physiological Society