Enhancing effect of vagotomy and pyloroplasty on gastro-intestinal carcinogenesis induced by nitrosamide in hamsters.

The possible promoting effect of vagotomy and pyloroplasty on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced carcinogenesis in the gastrointestinal (GI) tract was studied in Syrian golden hamsters on high fat diet (10% corn oil). After truncal vagotomy and pyloroplasty or sham operation, 50 micrograms/ml of MNNG was given for 4 months in drinking water. Similarly operated or non-operated animals without carcinogen administration served as controls. Spindle cell sarcomas were frequently seen in the MNNG-treated hamsters as well as spindle cell proliferation. After vagotomy and pyloroplasty, a small number of hamsters also developed adenocarcinomas and rosette-forming neurogenic tumors. The tumor development in the glandular stomach or small intestine was significantly increased after truncal vagotomy and pyloroplasty. The data suggest that this operation has an enhancing effect on the MNNG carcinogenesis in the hamster.