Rocz Panstw Zakl Hig 1997, 48(3): 229-237

Wpływ permetryny i DDT na aktywność form molekularnych cytochromu P-4501A i 2B w wątrobie szczura
[Effect of permethrin and DDT on the activity of cytochrome P-4501A and 2B molecular forms in rat liver]

G. Kostka, D. Palut, B. Wiadrowska


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 monooxygenasc inducer (induces cyt. P-4502B). Male Wistar rats received permethrin and DDT for ^ days at 24 h intervals in daily oral doses of 1/10, 1/50 and 1/100 LD». 3-mcthylo- cholantrene and phénobarbital 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. Phénobarbital and the highest dose of permethrin (620 mg/kg b.w. x day ') 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 phénobarbital. It should be noted that both pesticides induced only slight increase in O-dealkylation of 7-etoxyresofurin (cyt. P-4501 A-mediated reaction). The present results indicate that permethrin as well as DDT shows the ability to induce the phenobarbital-type of cytochrome P-4502B.

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