Effect of hexavalent chromium on drug-metabolizing enzymes in male domesticated rabbits.
We studied the effect of chromium on the drug-metabolizing enzymes (DME) in male New Zealand white rabbits, Oryctolagus cuniculus, with and without pretreatment with phenobarbitone (PB) and promethazine (PM). The activities of cytochrome P-450 (183%), aniline hydroxylase (ANH, 265%), acetanilide hydroxylase (ACH, 160%), benzphetamine demethylase (BD, 112%), aminopyrine demethylase (AD, 97%), N,N,-dimethyl aniline demethylase (DAD, 72%), and cytochrome-c-reductase (100%) were increased after PB treatment. The activities of cytochrome b5 and N,N,-dimethyl aniline N-oxide (DAO) were, however, decreased 79% and 47%, respectively. Most of the DME remained unaffected after PM treatment except for the increase in ANH (55%), ACH (56%), and BD (16%). Potassium dichromate administered to rabbits at a dose of 8 mg/kg body weight/day for 5 days resulted in an increase in the activities of ANH (108%), BD (76%), AD (25%), and DAD (49%), while that of cytochrome b5 and DAO were inhibited 81 and 77%, respectively. There was no effect on the activities of cytochrome P-450, ACH, and cytochrome-c-reductase. Chromium, administered to PB-pretreated animals decreased the activities of ANH (41%), ACH (35%), BD (34%), AD (30%), DAD (51%), cytochrome-c-reductase (72%), and DAO (62%). Other enzymes remained unaffected. When administered to PM-pretreated animals, the activities of ANH, BD, AD, and DAD increased 34, 69, 24 and 54%, respectively, whereas activities of cytochrome b5 and DAO were decreased 96 and 68%, respectively. All other DME remained unaffected.
Anjum
F
F
Department of Zoology, University of the Punjab, Lahore, Pakistan.
Shakoori
A R
AR
Gorrod
J W
JW
D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000187:drug effects*; D002857:Chromium / Q000493:pharmacokinetics / Q000633:toxicity*; D015786:Cytochromes b5 / Q000187:drug effects; D007527:Isoenzymes / Q000187:drug effects; D008297:Male; D010089:Oxidoreductases, N-Demethylating / Q000187:drug effects*; D010105:Oxygenases / Q000187:drug effects; D011817:Rabbits
D007527:Isoenzymes; D002857:Chromium; C074702:chromium hexavalent ion; D015786:Cytochromes b5; D010105:Oxygenases; C020066:dimethylaniline monooxygenase (N-oxide forming); D001189:Aryl Hydrocarbon Hydroxylases; D010089:Oxidoreductases, N-Demethylating