Cell kinetics of gastric carcinoma and other gastric lesions in rats by N-methyl-N'-nitro-N-nitrosoguanidine with or without Tween 60.

Male Wistar rats were divided into three groups for studying the chronic effect of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), in continuous dose of 50 mg/L in drinking water, or 50 mg/L MNNG and 0.4% Tween 60 in drinking water. From the 2nd to 50th week after the administration of MNNG, every 3 or 5 rats were sacrificed and autopsied after the intraperitoneal injection of 1 muCi 3-H-thymidine/g body weight at 2- or 3-week intervals. The resected stomachs were studied morphologically and autoradiographically. Six cases of experimental gastric cancer were produced that fulfilled Stewart's criteria. Autoradiographically, there was no significant different in the flash labeling index in the normal antral mucosa, in the non-pathologic antral mucosa, and in the cancerous lesion, but generation time and DNA synthesizing time of the cancerous lesion were 2 or 3 times longer than those of the glandular stomach of normal rats reported by Galjaard. They were also longer than those of the non-pathologic antral mucosa of rats treated with MNNG. These experiments results were discussed, comparing with cell kinetics of the gastrointestinal tracts in man.