Influence of pyridoxal 5'-phosphate on ethanol-induced changes in histamine catabolism in the guinea pig.

In guinea pigs, chronic intragastric administration of a 20% ethanol solution for 18 days (in increasing doses from 5 to 10 g/kg/day) leads, on the 18th day, to an enhancement of histamine level in the liver and the small intestine by up to 170% and 180% respectively. In these tissues the rate of histamine oxidative catabolism was depressed by about 20%. Histamine N-methyltransferase activity, as well as the level of acetylhistamine were not affected. Pyridoxal 5'-phosphate (2 mg/animal/day) tended to normalize both histamine levels and the rate of histamine oxidative catabolism.