||Effect of Coadministration of Phenobarbital Sodium on N-Nitrosodiethylamine-Induced Gamma-Glytamyltransferase-Positive Foci and Hepatocellular Carcinoma in Rats.
Pereira, M. A. ;
Herren-Freund, S. L. ;
Britt, A. L. ;
Khoury, M. M. ;
||Health Effects Research Lab., Cincinnati, OH. ;Cincinnati Univ., OH. Coll. of Medicine.
Environmental surveys ;
Laboratory animals ;
Nitrogen organic compounds ;
GGTase-positive foci ;
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
The effect of concurrent administration of phenobarbital on the hepatocarcinogenicity of N-nitrosodiethylamine (diethylnitrosamine; DENA) in rats was investigated by determination of the incidence of gamma-glutamyltransferase (gamma-glutamyltranspeptidase) (GGT)-positive foci and liver tumors. Male outbred Sprague-Dawley rats received either a weekly oral dose of DENA (0.08 mol/kg), phenobarbital sodium (500 ppm) in their drinking water, or DENA and phenobarbital sodium concurrently. After 16 weeks, only the animals treated concurrently with DENA and phenobarbital sodium had GGT-positive foci (3.65 foci/sq cm). At 30 weeks, the group treated with DENA and phenobarbital sodium exhibited more foci (23.6 foci/sq cm) compared to the group that received only DENA (3.08 foci/sq cm). The average size of foci in both of the DENA-treated groups was the same. The tumors in the group that received DENA plus phenobarbital sodium showed a greater incidence of GGT activity compared to the tumors in the DENA group. Under the conditions of this study the incidence of GGT-positive foci did not predict the incidence of hepatocellular carcinomas.