title: Remarkable difference in the incidence of liver tumors by N-nitrosodimethylamine in carcinogen-resistant DRH rat and its parental strain Donryu rat.
abstract: The carcinogen-resistant inbred DRH rat strain was developed from the carcinogen-sensitive Donryu rat and showed a remarkably lower incidence of liver tumors than the latter after administration of either 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) or 2-acetylaminofluorene (2-AAF). In the present study, we examined the tolerance of DRH rat to another type of hepatocarcinogen, that is, N-nitrosodimethylamine (DMN). Male DRH and Donryu rats, 3 weeks of age, were given a single i.p. injection of 10 mg/kg body weight DMN and were sacrificed 1 year later. Five of 11 Donryu rats (45%) had macroscopically detectable tumors: 9 liver tumors in 4 rats and 1 urinary bladder tumor in the other rat. On the contrary, no tumors were detectable in the livers or other organs of 10 DRH rats under the same conditions. These results and other circumstantial evidence indicate that the different susceptibility of chemical carcinogenesis between DRH and Donryu rats is independent of individual pathways of metabolic activation of carcinogens.
authors.affiliation: Department of Biochemistry, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yan
authors.forename: K
authors.initials: K
authors.lastname: Higashi
authors.forename: A
authors.initials: A
authors.lastname: Tanimoto
authors.forename: Y
authors.initials: Y
authors.lastname: Fukamachi
authors.forename: H
authors.initials: H
authors.lastname: Itoh
authors.forename: T
authors.initials: T
authors.lastname: Abe
authors.forename: T
authors.initials: T
authors.lastname: Higashi
mesh_terms: D000818:Animals; D002273:Carcinogens; D004128:Dimethylnitrosamine; D004198:Disease Susceptibility; D004361:Drug Tolerance; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity; D004124:p-Dimethylaminoazobenzene
chemical_list: D002273:Carcinogens; D004124:p-Dimethylaminoazobenzene; D004128:Dimethylnitrosamine