2-Aminofluorene-DNA adducts in mouse urinary bladder: effect of age, sex and acetylator phenotype

Abstract

Formation of urinary bladder DNA-2-aminofluorene adducts in inbred and acetylator congenic mice was measured 3 h after a 60 mg/kg dose of the arylamine carcinogen. The sensitivity of 32P-postlabeling with HPLC analysis permitted quantitation of adducts in individual mouse bladders. Acetylator phenotype was a significant determinant of DNA damage in female mice as slow acetylators had higher levels of bladder DNA adducts than rapids. This correlation is the reverse of that seen with hepatic DNA. Age was also a significant determinant of DNA damage as older mice (20-23 weeks) formed more bladder DNA adducts than young (7 week) mice. The age-related increase in bladder adduct formation was seen in both sexes of all mouse lines. Male B6 mice exposed to 2-aminofluorene at 20-23 weeks of age showed a 26-fold higher level of bladder DNA adducts than males exposed at 7 weeks. In addition to the large increase in total adduct level, the older male B6 mice produced significant amounts of an unidentified, early-eluting adduct peak that had chromatographic properties similar to an aminofluorene-DNA adduct produced through peroxidative activation. These results indicate that age, sex and acetylator phenotype are all important determinants of aromatic amine-bladder DNA adduct formation in mice.