Reduction and enhancement by phenobarbital of hepatocarcinogenesis induced in the rat by 2-acetylaminofluorene.

The effects of dietary phénobarbital on hepatocarcinogenesis in rats fed 2-acetylaminofluorene (AAF) were studied. The simultaneous feeding of AAF and phénobarbital reduced the hepatocarcinogenic effects of AAF. In contrast, the sequential feeding of AAF and phénobarbital resulted in a significant increase in the incidence of hepatomas. No ill effects were observed in rats fed phénobarbitalalone. AAF and phénobarbitaleach stimulated the proliferation of hepatocytes, but, whereas the effect of AAF was maintained for the duration of exposure, the effect of phénobarbital was short lived. Phénobarbital fed simultaneously with AAF decreased the effect of AAF on liver cell proliferation.