EFFECT OF COADMINISTRATION OF PHENOBARBITAL SODIUM ON N-NITROSODIETHYLAMINE-INDUCED GAMMA-GLYTAMYLTRANSFERASE-POSITIVE FOCI AND HEPATOCELLULAR-CARCINOMA IN RATS

  • 1 January 1984
    • journal article
    • research article
    • Vol. 72  (3) , 741-744
Abstract
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 wk, only the animals treated concurrently with DENA and phenobarbital sodium had GGT-positive foci (3.65 foci/cm2). At 30 wk, the group treated with DENA and phenobarbital sodium exhibited more foci (23.6 foci/cm2) compared to the group that received only DENA (3.08 foci/cm2). 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 to this study the incidence of GGT-positive foci did not predict the incidence of hepatocellular carcinomas.