Bc. Eke et al., AGE-DEPENDENT DIFFERENTIAL-EFFECTS OF CIGARETTE-SMOKE ON HEPATIC AND PULMONARY XENOBIOTIC-METABOLIZING ENZYMES IN RATS, Archives of toxicology, 71(11), 1997, pp. 696-702
The effects of cigarette smoke (CS) on hepatic and pulmonary monooxyge
nase (MO) activities (aniline 4-hydroxylase, AH; aminopyrine N-demethy
lase, AMND, 7-ethoxyresorufin O-deethylase, EROD; p-nitroanisole O-dem
ethylase, p-NAOD), lipid peroxidation (LP), and reduced glutathione (G
SH) levels and glutathione S-transferase (GST) activities toward sever
al substrates (1-chloro-2,4-dinitrobenzene, CDNB; 1,2-dichloro-4-nitro
benzene, DCNB; ethacrynic acid, EAA; 1,2-epoxy-3-(p-nitrophenoxy)-prop
ane, ENPP) were determined in 20-, 90- and 360-day-old male rats. The
animals were exposed to CS five times a day, with 1 h intervals, for 3
days in a chamber supplied alternatively with smoke and fresh air, an
d were killed 16 h after the last treatments. The hepatic AH activity
increased significantly in 20-day-old rats and remained unaltered in o
lder age groups. The hepatic AMND activity unaltered, significantly in
creased and decreased in 20-, 90 and 360-day-old rats? respectively. T
he pulmonary AH activity increased significantly in 20- and 90-day-old
rats whereas no alteration was noted in 360-day-old rats. CS was inef
fective on pulmonary AMND activity at all ages. CS increased hepatic a
nd pulmonary EROD and p-NAOD activities significantly in all age group
s compared to controls. In liver, LP level was significantly increased
, decreased, and unaltered in 20-, 90- and 360-day-old rats, respectiv
ely. CS increased hepatic GSH level significantly in 90-day-old rats b
ut was not effective in the other age groups. In lung, LP level was in
creased in 90- and 360-day-old rats and unaltered in 20-day-old rats.
CS increased pulmonary GSH level significantly in 90-day-old mts and d
id not have any effect in the other age groups. The hepatic GST activi
ties toward CDNB and DCNB decreased significantly in 360-day-old rats
and were unaltered in the younger age groups. The hepatic GST activity
toward EAA was unaltered, significantly increased and decreased in 20
-, 90- and 360-day-old rats! respectively. The hepatic GST activity to
ward ENPP decreased significantly in 20- and 90-day-old rats but was u
naltered in the oldest group of rats. In 20-day-old rats, the pulmonar
y GST activity toward ENPP increased significantly whereas the other G
ST activities did not alter. In 90-day-old rats, however, CS significa
ntly decreased all the pulmonary CST activities studied. Unaltered DCN
B GST, significant increase in EAA GST and decrease in CDNB and ENPP G
ST activities of lung were noted in 360-day-old rats. These results re
veal that the regulation in rats of hepatic and pulmonary MO and GST a
ctivities are differentially influenced by CS as a function of age.