Effect of taurocholic acid feeding on methyl-nitro-N-nitroso-guanidine induced gastric tumors.

Bile reflux is generally accepted as a causative factor of gastric cancer after partial gastrectomy. The present study was designed to evaluate the promotion, by the per oral administration of taurocholic acid, of methyl-N-nitro-N'-nitrosoguanidine (MNNG)-induced gastric carcinogenesis. MNNG (83 mg/l) was given in the drinking water to half the male Wistar rats during 12 weeks while the other half served as controls. After this treatment half of the MNNG-treated animals and half of the controls were placed under a diet containing 0.2% of taurocholic acid while the other animals received the standard diet. At the 40th week after initiation of MNNG, surviving animals were killed. Their stomachs and their duodenums were observed for macro and microscopic examination. Macroscopically there were 7 animals bearing gastric tumors in the MNNG group and 15 in the MNNG + bile group (P less than 0.05). Microscopically there were 7 animals with severe antral dysplasia in the MNNG group, 7 rats with fundic dysplasia and 18 with severe antral dysplasia in the MNNG + bile group. Both groups developed an identical number of duodenal tumors which were invasive adenocarcinomas or angiosarcomas. In this experiment taurocholic acid significantly promoted gastric carcinogenesis. It is postulated that surgical techniques inducing duodenal reflux in the stomach may produced a 'high risk' group of patients in which a long and careful follow-up is required.