MOLECULAR DOSIMETRY OF DNA ADDUCTS IN C3H MICE TREATED WITH BISPHENOL-A DIGLYCIDYLETHER

The formation of a glycidaldehyde-DNA adduct in skin of C3H mice treated with [C-14]bisphenol A diglycidylether has been previously reported and it was assumed that the modification occurred on guanine residues. We were interested in elucidating the structure of this glycidaldehyde-DNA adduct by using a non-radioactive approach. Male C3H mice were treated with a single topical dose of 2 mg bisphenol A diglycidylether in acetone for 48, % or 192 h. An additional two mice were treated with 2 mg glycidaldehyde in acetone for 24 h. Epidermal DNA was isolated and enzymatically digested to nucleoside-3'-monophosphates. Aliquots of the DNA hydrolysates were separated on HPLC using a reverse-phase column with a potassium dihydrogen phosphate/methanol gradient. Fluorescence analysis of the eluent indicated the presence of a fluorescent DNA adduct, which was identified as hydroxymethylethenodeoxyadenosine-3'-monophosphate by comparison with a synthetic reference standard. Amounts of adducts were determined by fluorescence measurements using a calibration curve obtained with the authentic adduct standard. Irrespective of duration of exposure, all DNA hydrolysates of treated mice contained similar amounts of the deoxyadenosine adduct. The alkylation frequency was 0.1-0.8 and 166 adducts/10(6) normal nucleotides for the treatment with bisphenol A diglycidylether and glycidaldehyde respectively. The limit of detection using 500-mu-g DNA samples for analysis was approximately 0.03 adducts/10(6) normal nucleotides.