K. Pina et D. Segerback, P-32 POSTLABELING OF DNA-ADDUCTS FORMED BY ALLYL GLYCIDYL ETHER IN-VITRO AND IN-VIVO, Carcinogenesis, 18(8), 1997, pp. 1457-1462
P-32-Postlabelling analysis of allyl glycidyl ether-treated DNA after
adduct enrichment on anion-exchange cartridges revealed two major and
one minor DNA adducts, The major adducts were shown to originate from
alkylation at N-7-guanine and N-1-adenine, respectively, while the min
or adduct was at N-3-cytosine. In addition, rearrangement products of
the l-adenine and 3-cytosine adducts to N-6-adenine and 3-uracil were
indicated, The relative amounts of adenine, cytosine and uracil produc
ts appeared to be dependent upon conditions (in particular pH) during
sample processing and analysis, When nuclease P1 was used for adduct e
nrichment the adenine, cytosine and uracil adducts, but not the 7-guan
ine adduct, were detected, The labelling efficiency of the 7-guanine a
dduct standard was 40-45%. Total recovery of this adduct from allyl gl
ycidyl ether-modified DNA was 9-12%, The labelling efficiency of the l
-adenine adduct standard was 78-82%, Total recovery of this adduct fro
m DNA was similar to 20% when using anion-exchange chromatography for
adduct enrichment and 30-34% when using nuclease P1, Preliminary analy
sis of DNA from mice treated with allyl glycidyl ether indicated 57 ti
mes higher level of the 7-guanine adduct, per unit dose, in skin DNA (
120 per 10(8) normal nucleotides) after topical application when compa
red to liver DNA after i,p. administration, The l-adenine adduct could
not be quantified in liver DNA (due to an interfering background prod
uct present in untreated animals) and the level of the 3-cytosine addu
ct was below the detection limit of the method. After topical applicat
ion the level of the 1 adenine adduct in skin DNA was similar to 30 pe
r 10(8), using either column or nuclease P1 enrichment, The 3-cytosine
adduct was detected in skin, but was not quantified.