Enhancement by prolonged administration of caerulein of experimental carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in rat stomach.

The effect of caerulein on the incidence and histology of gastric adenocarcinomas induced by N-methyl-N'-nitro-N-nitrosoguanidine was investigated in inbred Wistar rats. Prolonged alternate-day administration of caerulein at 10 micrograms/kg body weight after treatment with the carcinogen for 20 weeks significantly increased the incidence and number of adenocarcinomas of the glandular stomach. Histological examination showed that treatment with caerulein had no influence on the histology of induced adenocarcinomas. Furthermore, administration of caerulein resulted in a significant increase in the bromodeoxyuridine-labeling indices of the antral mucosa but did not influence the bromodeoxyuridine-labeling indices of the fundic mucosa and the carcinomas. These findings indicate that caerulein enhances gastric carcinogenesis and that the effect may be related to the promoting effect of caerulein on cell proliferation in the antral mucosa.