A. Kopplin et al., URINARY-EXCRETION OF 3-METHYLADENINE AND 3-ETHYLADENINE AFTER CONTROLLED EXPOSURE TO TOBACCO-SMOKE, Carcinogenesis, 16(11), 1995, pp. 2637-2641
The urinary excretion of the DNA alkylation products 3-methyladenine (
3-MeAde) and 3-ethyladenine (3-EtAde) after controlled exposure to cig
arette smoke over a period of 4 days was determined by competitive rad
ioimmunoassay after separation by HPLC, Twenty-four hour urine samples
were collected from five smokers and five non-smokers, Days 1 and 3 (
control days) were without smoking, on days 2 and 4 smokers consumed 2
4 cigarettes each within 8 h in an unventilated room (45 m(3)) in the
presence of nonsmokers. Average levels of carbon monoxide during expos
ure were 15-20 p.p.m., 2.8-3.5 mg/m(3) of respirable suspended particl
es and 75-86 mu g/m(3) of nicotine, Carboxyhemoglobin levels increased
by 9.0 and 1.8% in smokers and passive smokers respectively. On contr
ol days, urinary excretion of 3-MeAde was similar in smokers and nonsm
okers (4.7-6.2 mu g/24 h), Smoking resulted in a significant increase
(P < 0.01) in 3-MeAde excretion (13.6-14.8 mu g/24 h); no change was o
bserved in the average excretion of 3-MeAde by passive smokers (4.8-4.
9 mu g of 3-MeAde/24 h). Baseline 3-EtAde excretion on control days wa
s similar in smokers and passive smokers (13.7-32.8 ng/24 h). In smoke
rs, the amount of urinary 3-EtAde was increased >5-fold (119.3-138.5 n
g/24 h) on smoking days; no effect on 3-EtAde excretion was observed o
n average in passive smokers (18.0-25.2 ng/24 h), The nature of the DN
A-reactive agent(s) responsible for the increased urinary excretion of
3-alkyladenines, in particular of the sensitive indicator 3-EtAde, re
mains to be determined.