Induction of changes in the pepsinogen content and the pepsinogen isoenzyme pattern of the pyloric mucosa of the rat stomach by short-term administration of stomach carcinogens.

Changes in pepsinogen isoenzyme patterns were examined in the pyloric mucosae of the stomachs of noninbred male Wistar rats after short-term administration of gastric carcinogens. N-Methyl-N-nitro-N-nitrosoquanidine, N-ethyl-N1-nitro-N-nitrosoguanidine, and N-propyl-N-nitro-N-nitrosoguanidine, which induce stomach cancer in rats, decreased the content of pepsinogen isoenzyme 1 )Pg 1), which was separated by poly-acrylamide gel electrophoresis. They also decreased the pepsingoen content of the pyloric mucosa. 4-Nitroguinoline 1-oxide, which induces a low incidence of stomach cancer in rats, rarely decreased the Pg 1 content or the pepsinogen content of the pyloric mucosa, and the incidence of such decreases was not statistically significant. However, diethylnitrosamine and dimethylnitrosamine, which do not induce stomach cancer in rats, did not cause any decrease in pepsinogen content. Ethyl methanesulfonate, a direct-acting carcinogen used as a control, also did not decrease the pepsinogen content.