Quantification of 7-(2-hydroxyethyl)guanine (7-HEG) adduct in DNA of l
ivers and lymphocytes of male Sprague-Dawley rats exposed to 300 ppm e
thene by inhalation (12 h a day for three consecutive days) was perfor
med to evaluate the potential of ethene to produce DNA adducts in thes
e tissues. The persistence of 7-HEG in livers and lymphocytes was stud
ied in rats sacrificed 0, 1, 5, and 20 days after the last exposure, D
NA samples from control and treated animals were analysed for 7-HEG an
d 7-methylguanine (7-MG) adducts by thin-layer chromatography (TLC) co
mbined with a high pressure liquid chromatography (HPLC) assay, After
a 8-day exposure to ethene, 7-HEG accumulated to a similar extent in l
iver and lymphocytes, with the mean adduct level of 7.0 +/- 0.7 adduct
s per 10(7) nucleotides in liver and 7.4 +/- 0.7 adducts per 10(7) nuc
leotides in lymphocytes of rats sacrificed immediately after cessation
of exposure. The approximate half-life of 7-HEG was 5 days in liver a
nd 3 days in lymphocytes, which is consistent with the loss of adduct
primarily by spontaneous depurination. In addition, the background lev
els of 7-HEG and 7-MG were determined in the liver and lymphocytes fro
m the control rats.