Record Display for the EPA National Library Catalog


OLS Field Name OLS Field Data
Main Title Initiation/Promotion Bioassay in Rat Liver: Use of Gamma Glutamyltranspeptidase-Positive Foci to Indicate Carcinogenic Activity.
Author Pereira, M. A. ; Herren-Freund, S. L. ; Britt, A. L. ; Khoury, M. M. ;
CORP Author Cincinnati Univ., OH. Coll. of Medicine.;Health Effects Research Lab., Research Triangle Park, NC.
Year Published 1982
Report Number EPA-68-03-2870; EPA/600/J-82/436;
Stock Number PB84-244110
Additional Subjects Toxicology ; Bioassay ; Liver ; Carcinogens ; Laboratory animals ; Rats ; Environmental surveys ; Reprints ; Biological indicators ; Traspeptidase/glutamyl ; Cancer
Library Call Number Additional Info Location Last
NTIS  PB84-244110 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 06/23/1988
Collation 12p
Gamma Glutamyltranspeptidase (GGTase)-positive foci have been used to indicate activity in an initiation/promotion bioassay in rat liver. This rat liver foci bioassay has been proposed for inclusion in tier 2 of a three tier decision tree approach to carcinogenesis testing where it would function to confirm carcinogenic activity. The assay was sensitive to hepatocarcinogens and some non-hepatocarcinogens and was able to distinguish between tumor initiators and tumor promoters. The induction of GGTase-positive foci by methylating agents was associated with the formation of O sup 6 methylguanine and not N-7 methylguanine, which would indicate a mutagenic origin for the foci. The foci once induced did not regress over the life time of the animal. Zonal induction of GGTase activity was induced by some promoters which confounded the scoring of foci incidence. The results to date indicate that the rat liver foci bioassay warrants further validation for inclusion in tier 2 and emphasizes the need to demonstrate the predictive and precursor relationship of GGTase-positive foci to cancer. (Copyright (c) 1982 by the Society of Toxicologic Pathologists)