Conjugation of 1-naphthol in the gastric mucosa of guinea pigs

1-Naphthol was conjugated in tissue pieces of the gastric wall to naphthol glucuronide (85%) and naphthol sulfate (15%). There was no regioselectivity in different parts of the stomach. In separated gastric mucosal cell populations, the activities of both transferases were highest in the mucous cell fraction (apparent V max of glucuronidation: 0.83 nmol/mg protein/min; apparent V max of sulfation: 0.11) with only little, or no activity in chief cells and parietal cells. Immunohistochemically glucuronosyltransferase 1 was predominantly localized in surface mucous cells. In conclusion, the gastric mucosa is an important organ for phase II biotransformation.