title: Enhancement of dimethylnitrosamine-initiated hepatocarcinogenesis in hamsters by subsequent administration of carbon tetrachloride but not phenobarbital or p,p'-dichlorodiphenyltrichloroethane.
abstract: The effect of phenobarbital (PB), p,p'-dichlorodiphenyltrichloroethane (DDT) or carbon tetrachloride (CCl4) on dimethylnitrosamine (DMN)-induced hepatocarcinogenesis in Syrian golden hamsters was examined. Hamsters were given a single injection of DMN (6 mg/kg body wt) followed by either PB or DDT in the diet or repeated CCl4 gavage for 30 weeks. The numbers of both altered liver cell foci and hepatocellular neoplasms in the hamsters given 0.1 ml CCl4, i.g. once every 2 weeks after the DMN were significantly higher than in the animals given DMN alone. PB or DDT (500 p.p.m. in the diet) after DMN did not produce a significantly higher incidence of altered foci or hepatocellular neoplasms compared to DMN alone. Thus, an enhancing effect of CCl4 on DMN-induced hepatocarcinogenesis in the hamster was demonstrated, but neither PB or DDT--both liver neoplasm promoters in rats and mice--displayed promoting activity under the conditions of study.
authors.forename: T
authors.initials: T
authors.lastname: Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Mori
authors.forename: G M
authors.initials: GM
authors.lastname: Williams
mesh_terms: D000818:Animals; D002251:Carbon Tetrachloride / Q000633:toxicity*; D003043:Cocarcinogenesis; D006224:Cricetinae; D003634:DDT / Q000633:toxicity*; D004128:Dimethylnitrosamine; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced* / Q000473:pathology; D008297:Male; D008647:Mesocricetus; D010634:Phenobarbital / Q000633:toxicity*; D013045:Species Specificity
chemical_list: D003634:DDT; D002251:Carbon Tetrachloride; D004128:Dimethylnitrosamine; D010634:Phenobarbital