Effect of a defined diet in liquid form on gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats.

The effect of ad libitum feeding of a defined diet in liquid form on the incidence of gastric adenocarcinomas induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was investigated in Wistar rats. Fresh defined diet was supplied once every 24 h from 2 weeks before oral administration of MNNG to the end of the experiment in week 52. Oral administration of the defined diet resulted in significant decrease in the incidence of gastric cancers in experimental week 52. It also caused a significant increase in the incidence of atypical glandular hyperplasia, which is a precursor of gastric cancer. Furthermore, administration of the defined diet for 30 and 52 weeks also resulted in significant decrease in the serum gastrin level and the marked gastric mucosal hypoplasia. These findings indicate that the defined diet in liquid form inhibited the development of gastric cancers and that this effect may have been related to its effect in decreasing proliferation of cells in the antral mucosa.