Promotion by neurotensin of gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats.

The effects of neurotensin on the incidence and histology of gastric cancers induced by N-methyl-N'-nitro-N-nitrosoguanidine were investigated in Wistar rats. Rats were given 100 or 200 micrograms per kg of body weight of neurotensin s.c. every other day in depot form after 25 wk of p.o. treatment with the carcinogen. Prolonged alternate-day administration of neurotensin at 200 micrograms per kg of body weight resulted in a significant increase in the incidence of gastric cancers of the glandular stomach by Wk 52. However, it did not influence the histological appearance of the gastric cancers. Furthermore, it caused a significant increase in the labeling indices of the epithelial cells of the antrum and of gastric cancers. In contrast, the administration of neurotensin at 100 micrograms per kg of body weight had a slight, but not significant, influence on the development of gastric cancers. These findings indicate that neurotensin promotes gastric carcinogenesis, and that this effect may be related to its effect in increasing proliferation of epithelial cells in the antral mucosa and in gastric cancers.