Protection by oral phenylalanine against gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats.

The effect of oral administration of L-phenylalanine on the incidence and histology of gastric adenocarcinomas induced by N-methyl-N'-nitro-N-nitrosoguanidine was investigated in inbred Wistar rats. Oral administration of 6% phenylalanine after 25 weeks of treatment with the carcinogen significantly reduced the incidence and number of adenocarcinomas of the glandular stomach at experimental week 52. Oral administration of high dose phenylalanine significantly increased the basal serum gastrin level and significantly decreased the norepinephrine concentration in the antral portion of the gastric wall, as well as the labelling indices of antral mucosa. These findings indicate that orally administered phenylalanine inhibits the development of gastric cancers.