[The effect of permethrin and DDT on the activity of cytochrome P-450 1A and 2B molecular forms in rat liver].
The effect of permethrin on relative liver weight (RLW) and the activity of hepatic monooxygenase system related to cytochrome P-4502B and 2A was studies. The effect of permethrin was compared with DDT used as phenobarbital-type of monooxygenase inducer (induces cyt. P-4502B). Male Wistar rats received permethrin and DDT for 4 days at 24 h intervals in daily oral doses of 1/10, 1/50 and 1/100 LD50. 3-methylocholantrene and phenobarbital which served as inducers of cytochrome P-4501A and 2B, respectively and were used as positive controls. The activities of cytochrome(s) P-450 were measured by 7-pentoxy- and 7-etoxyresofurin O-dealkylation by S-9 fraction of rat liver; these two compounds have been shown to be the substrates for reactions mediated by cytochrome P-4502B and 2A. Thus this biochemical procedure permits to determine whether tested compound belongs to one of two main types of inducers of the cytochrome P-450 monoxygenase system. Treatment of rats with both pesticides resulted in significant increase in RLW, to 30 and 15% of control, respectively. In animals treated with permethrin the metabolism of 7-pentoxyresofurin increased in a dose dependent manner. Phenobarbital and the highest dose of permethrin (620 mg/kg b.w. x day-1) induced similar (about 30-fold) increase in O-dealkylation of 7-pentoxyresofurin. DDT stimulated metabolism of 7-pentoxyresofurin to much higher degree as compared with phenobarbital. It should be noted that both pesticides induced only slight increase in O-dealkylation of 7-etoxyresofurin (cyt. P-4501A-mediated reaction). The present results indicate that permethrin as well as DDT shows the ability to induce the phenobarbital-type of cytochrome P-4502B.
Kostka
G
G
Zakład Toksykologii Srodowiskowej, Państwowy Zakład Higieny.
Palut
D
D
Wiadrowska
B
B
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000187:drug effects*; D003634:DDT / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D007306:Insecticides / Q000633:toxicity*; D008099:Liver / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008297:Male; D009929:Organ Size / Q000187:drug effects; D026023:Permethrin; D010634:Phenobarbital / Q000633:toxicity; D011722:Pyrethrins / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar
D007306:Insecticides; D011722:Pyrethrins; D026023:Permethrin; D003577:Cytochrome P-450 Enzyme System; D003634:DDT; D010634:Phenobarbital