Enhancing effect of ethanol on aflatoxin b1-induced DNA-damage in glutathione-depleted rat hepatocytes

The effect of reduced glutathione (GSH) and ethanol on aflatoxin B1 (AFB1)-induced DNA single strand breaks was studied in primary cultured hepatocytes. Buthionine sulfoximine (BSO) which decreased intracellular GSH to 13% of those of the control levels increased DNA fragmentation of AFB1-treated hepatocytes by over 17% of those without BSO. Thus, a decrease in hepatocyte GSH levels increased AFB1-induced DNA damage. Although ethanol in itself did not induce DNA damage, a combination of BSO and ethanol increased the percentage by over 23% of that with BSO only. Ethanol did not affect the amount of GSH, total cytochrome P-450 (P450), glutathione S-transferase (GST) and epoxide hydrolase (EHase) in cultured hepatocytes. However, GSH-depleted rat hepatocytes exposed to ethanol significantly increased the level of P450IIIA, which activates AFB1. The enhancing effects of ethanol in the presence of BSO are probably due to the induction of this isozyme in rat hepatocytes. The GSH-depleted hepatocytes are more susceptible to chemical carcinogens in the presence of ethanol.