N-METHYL-N-NITROSOUREA CONCENTRATION-DEPENDENT, RATHER THAN TOTAL INTAKE-DEPENDENT, INDUCTION OF ADENOCARCINOMAS IN THE GLANDULAR STOMACH OF BALB C MICE/

Citation
T. Yamachika et al., N-METHYL-N-NITROSOUREA CONCENTRATION-DEPENDENT, RATHER THAN TOTAL INTAKE-DEPENDENT, INDUCTION OF ADENOCARCINOMAS IN THE GLANDULAR STOMACH OF BALB C MICE/, Japanese journal of cancer research, 89(4), 1998, pp. 385-391
Citations number
36
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Oncology
ISSN journal
0910-5050
Volume
89
Issue
4
Year of publication
1998
Pages
385 - 391
Database
ISI
SICI code
0910-5050(1998)89:4<385:NCRTTI>2.0.ZU;2-S
Abstract
The influence of the level of carcinogen exposure on histopathological types and cellular differentiation of the induced tumors was examined in 100 male BALB/c mice given N-methyl-N-nitrosourea (MNU) in their d rinking water at 240 ppm on alternate weeks (total exposure: five week s) (group 1), at 120 ppm similarly (total exposure: ten weeks) (group 2), at 60 ppm for 20 weeks continuously (group 3), or at 30 ppm for 40 weeks continuously (group 4), Forty-three differentiated and 17 undif ferentiated type adenocarcinomas were induced. Glandular stomach carci nomas and undifferentiated type lesions were more common in mice treat ed with a high concentration of MNU for a short period than,vith a low concentration of MNU for a long period, even though total measured in take of MNU was smaller (P<0.01). All the induced glandular stomach ca rcinomas, independent of the treatment schedule, consisted entirely of gastric phenotype cells. In conclusion, the induction of glandular st omach cancers and the proportion of undifferentiated type lesions depe nd not on the total quantity, but rather on the concentration of the c arcinogen, while the phenotypic expression of tumor cells is not affec ted by the differences in the administration protocol.