芳香烃羟化酶活性与苯并[a]芘中间代谢产物生成关系的研究

100mg香烟烟油,多氯联苯诱导大鼠肝S_9组分中芳香烃羟化酶代谢B[a]P为3-OH-B[a]P的活性分别升高约40,20倍,而代谢B[a] P生成6-OXY-B [a]P自由基产物却仅由多氯联苯诱导的S_9组分作用中才被观察到。

Studies on Relationship between Activities of Aryl Hydrocarbon Hydroxylase and Intermediate Products of Benzo(a)pyrene

In our experiment, polychlorinated biphenyls and cigarette smoke tar were administered intraperitoneally to different groups of rats from which S9 fractions of liver were prepared. The activities of AHH from these S9 fractions were determined by measuring fluorescence of 3-OH-B ( a ) P and found to be about 20 and 40 times higher than that of the control respectively, the latter receiving dimethylsulfoxide alone or no injection. However, after incubating B(a)P with NADPH-cofactors and respective S9 fraction metabolite 6-oxy-B ( a ) P free radical was extracted and detected by means of electron spin resonance ( ESR ) method. We found that free radical signal was only observed in the extractant which was obtained by incubating B ( a ) P with S9 fraction from liver of polychlorinated biphenylstreated rats, but no ESR signal was observed in other extractant. It is clear that B ( a ) P is oxygenated mainly at the C3 position by catalysis of AHH obtained from rats which was pretreated by 100mg cigaratte smoke tar to form 3-OH-B (a ) P, while AHH obtained from rats pretreated with polychlorinated biphenyls not only catalyze B (a) P at C3 position but also at C6 position to form 6-Oxy-B ( a ) P radical.