Modulation of aflatoxin B1-induced glutathione S-transferase placental form positive hepatic foci by pretreatment of rats with phenobarbital and buthionine sulfoximine.

Induction of glutathione S-transferase placental form (GST-P) positive hepatic foci has been examined by immunohistochemical analysis in young male Fischer rats 3 weeks after a single i.p. injection of aflatoxin B1 (AFB1). Pretreatment of rats with L-buthionine sulfoximine (BSO), a GSH depleter, at a dose of 4 mmol/kg body wt 4 and 2 h before 1.0 mg AFB1 treatment enhanced both the number of AFB1-induced hepatic foci and the area occupied by these foci by approximately 400 and 575% above their respective controls without affecting the mean diameter of these foci. Pretreatment of rats with 0.1% phenobarbital (PB) in their drinking water for 1 week before AFB1 (1 mg) treatment, inhibited AFB1-induced foci almost completely. However, the number of AFB1-induced foci in PB-pretreated rats was not significantly increased by BSO pretreatment.