Alteration of rat liver microsomal monooxygenase activities by gasoline treatment.
Previous work has shown an increase in rat liver enzyme activities after chronic exposure to gasoline vapor. In the present study, male Sprague-Dawley rats were pretreated with unleaded gasoline at 1 and 5 ml/kg, i.p., and selected hepatic microsomal monooxygenase activities were determined at 18, 48, and 72 h. At 18 h, moderate increases were observed in P450 content (1.3-fold), cytochrome c-reductase activity (1.25-fold), and in N-nitrosodimethylamine demethylation rate (1.25- to 1.6-fold). Pentoxyresorufin dealkylase activity (an activity displayed primarily by P450IIB1) was significantly elevated at 18 and 48 h (30- to 60-fold), and ethoxyresorufin dealkylase activity (an activity displayed by P450 IA1) was elevated (2- to 4-fold). Immunoblot analysis revealed no change in P450IIE1 at these time points, but an elevation in P450IIB1 in agreement with the pentoxyresorufin dealkylase activity measurements.
Brady
J F
JF
Department of Chemical Biology and Pharmacognosy, College of Pharmacy, Rutgers University, Piscataway, NJ 08855.
Xiao
F
F
Gapac
J M
JM
Ning
S M
SM
Yang
C S
CS
D000818:Animals; D019363:Cytochrome P-450 CYP1A1; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis; D005742:Gasoline / Q000633:toxicity*; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects* / Q000201:enzymology; D009245:NADH Dehydrogenase / Q000032:analysis; D010088:Oxidoreductases / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains
D005742:Gasoline; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; D019363:Cytochrome P-450 CYP1A1; D009245:NADH Dehydrogenase