Repair of O6-methylguanine in rat liver DNA is enhanced by pretreatment with single or multiple doses of aflatoxin B1.

Pretreatment of rats by the repeated administration of certain alkylating carcinogens has been shown to stimulate the removal of O6-alkylguanine from hepatic DNA. Prolonged feeding with the aromatic amide 2-acetylaminofluorene has a similar effect. In this report, aflatoxin B1, an agent from another chemically distinct class of carcinogen, is shown to be capable of stimulating the repair of O6-methylguanine in hepatic DNA. The sensitivity of this system is shown by the fact that this repair response can be fully stimulated as early as 1 day after treatment with a single dose.