O6-methylguanine DNA adduct formation and modulation by ethanol in placenta and fetal tissues after exposure of pregnant patas monkeys to N-nitrosodimethylamine.

Perinatal nitrosamine exposures may contribute to childhood cancer risk. To test primate fetal susceptibility to formation of cancer initiation-related DNA adducts from nitrosamines, pregnant patas monkeys were given 1.0 or 0.1 mg/kg N-nitrosodimethylamine. Appreciable levels of the promutagenic O6-methylguanine adduct occurred in placental and fetal liver DNA after both doses and were lower but detectable in other fetal tissues after the higher dose. Coadministered ethanol (1.6 g/kg) reduced adducts in placenta and fetal liver by one-half and increased levels in other fetal tissues to the same degree. Thus, primate placenta and fetal tissues have a significant, ethanol-modulated capacity to activate N-nitrosodimethylamine, supporting implication of nitrosamines in human perinatal carcinogenesis and of alcohol as a modulating factor.