title: Different responses to phenobarbital promotion in the development of gamma-glutamyltranspeptidase-positive foci in the liver of rats initiated with diethylnitrosamine, N-hydroxy-2-acetyl-aminofluorene and aflatoxin B1.
abstract: The promoting activities of phenobarbital (PB) on the development of gamma-glutamyl-transpeptidase-positive (gamma-GT+) foci in rat liver with three different initiating agents were compared in a short-term system (8 weeks). Male F344 rats were initiated by a single application of 200 mg/kg of diethylnitrosamine (DEN), 30 mg/kg of N-hydroxy-2-acetylaminofluorene (N-OH-AAF), 1.0 or 0.5 mg/kg of aflatoxin B1 (AFB1) or the vehicles alone. Two weeks after the initiation, animals were placed on a 0.05% PB diet for 6 weeks. Partial hepatectomy was performed at the end of the third week of the experiment. As a positive control, some animals were fed diet containing 0.06% 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) after the initiation. The number and area of gamma-GT+ foci in the liver were quantified. All three initiators showed a summation effect with 3'-Me-DAB on the appearance of gamma-GT+ foci. Promotion by PB, however, was observed only in DEN-initiated rats and not in N-OH-AAF- or AFB1-initiated rats. It is apparent from the present experimental data that the promoting potential of PB on liver carcinogenesis depends on the initiating agent.
authors.forename: T
authors.initials: T
authors.lastname: Shirai
authors.forename: K
authors.initials: K
authors.lastname: Imaida
authors.forename: M
authors.initials: M
authors.lastname: Ohshima
authors.forename: S
authors.initials: S
authors.lastname: Fukushima
authors.forename: M S
authors.initials: MS
authors.lastname: Lee
authors.forename: C M
authors.initials: CM
authors.lastname: King
authors.forename: N
authors.initials: N
authors.lastname: Ito
mesh_terms: D016604:Aflatoxin B1; D000348:Aflatoxins / Q000633:toxicity*; D000818:Animals; D002273:Carcinogens; D003043:Cocarcinogenesis; D004052:Diethylnitrosamine; D006881:Hydroxyacetylaminofluorene; D008099:Liver / Q000201:enzymology*; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced*; D008297:Male; D010634:Phenobarbital / Q000633:toxicity*; D051381:Rats; D011916:Rats, Inbred F344; D005723:gamma-Glutamyltransferase / Q000032:analysis*
chemical_list: D000348:Aflatoxins; D002273:Carcinogens; D004052:Diethylnitrosamine; D006881:Hydroxyacetylaminofluorene; D016604:Aflatoxin B1; D005723:gamma-Glutamyltransferase; D010634:Phenobarbital