title: [The influence of castration on the induction of gastric adenocarcinoma by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in Wistar rats].
abstract: Six-week old non-castrated and castrated Wistar rats of both sexes, 20 in each group, received a continuous dose of 83 micrograms/ml MNNG in drinking water for 32 weeks. All animals were autopsied at the 52nd week for pathological examination. The incidence of the gastric adenocarcinoma was 31.6-50.0%, and no significant differences were obtained statistically between different MNNG-treated groups. No tumor was found in the control group. Quantitative and qualitative studies of the intramucosal cyst (IC) showed that the ICs might be classified into simple and dysplastic. The former was subdivided into 5 groups and the commonest type was fundic cyst (81%). In MNNG-treated groups, the number of fundic cysts was decreased; nevertheless, the neck cell cysts were increased in number markedly. The number of dysplastic cysts in the MNNG-treated groups was significantly increased and this important precancerous lesion was closely related with the genesis of gastric adenocarcinoma.
authors.forename: R F
authors.initials: RF
authors.lastname: Zhang
mesh_terms: D000230:Adenocarcinoma / Q000139:chemically induced / Q000473:pathology*; D000818:Animals; D002369:Castration; D005260:Female; D008297:Male; D008769:Methylnitronitrosoguanidine; D051381:Rats; D011919:Rats, Inbred Strains; D013274:Stomach Neoplasms / Q000139:chemically induced / Q000473:pathology*
chemical_list: D008769:Methylnitronitrosoguanidine