OXIDATION OF (+)-7,8-DIHYDROXY-7,8-DIHYDROBENZO[A]PYRENE BY MOUSE KERATINOCYTES - EVIDENCE FOR PEROXYL RADICAL-DEPENDENT AND MONOXYGENASE-DEPENDENT METABOLISM
OXIDATION OF (+)-7,8-DIHYDROXY-7,8-DIHYDROBENZO[A]PYRENE BY MOUSE KERATINOCYTES - EVIDENCE FOR PEROXYL RADICAL-DEPENDENT AND MONOXYGENASE-DEPENDENT METABOLISM
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DOI：
10.1093/carcin/7.12.1957
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发表时间：
1986-12-01
期刊：
影响因子：
4.7
通讯作者：
MARNETT, LJ
中科院分区：
文献类型：
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作者：
ELING, T;CURTIS, J;MARNETT, LJ
用无毛小鼠皮肤角质形成细胞研究了前列腺素H（PGH）合成酶、过氧自由基和细胞色素P-450在7，8-二羟基-7，8-二氢苯并[a]芘（BP-7，8-diol）代谢中的作用。标记的（+）-BP-7，8-二醇在与角质形成细胞孵育后氧化为顺式和反式二醇环氧化物，比例大于4：1，通过h.p.l.c.估计。稳定水解产物的分析。二醇环氧化物的形成依赖于细胞数量和BP-7，8-二醇的浓度。在PGH合成酶底物（20：4）或抑制剂吲哚美辛存在下孵育不会改变总形成或二醇环氧化物的比例。然而，加入过氧自由基依赖性代谢的抑制剂丁基化羟基茴香醚（1 μ M）显著抑制了二羟环氧化物的形成。测定了形成抗二羟环氧化合物和脂质过氧化（以丙二醛计）的时间过程。结果表明，过氧自由基和diolepoxide形成之间的良好的相关性。用细胞色素P-450诱导剂β-萘酮显著改变角质形成细胞对（+）-BP-7，8-二醇的代谢。主要代谢产物为顺式环氧二醇，并显著形成两种未知代谢产物。用BP-7，8-二醇预处理小鼠未诱导芳烃羟化酶活性，但使标记的（+）-BP-7，8-二醇形成的顺式二环己内酯的产率增加1.5倍。我们的研究结果表明，过氧自由基介导的代谢是主要负责（+）-BP-7，8-二醇在对照动物的氧化，而细胞色素P-450系统是主要负责在诱导剂预处理的动物的氧化。
The role of prostaglandin H (PGH) synthase and peroxyl radicals as well as cytochrome P-450 in the metabolism of 7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (BP-7,8-diol) was examined in fresh skin keratinocytes isolated from hairless mice. Labeled (+)-BP-7,8-diol was oxidized after incubation with the keratinocytes to syn- and anti-diolepoxides in greater than a 4:1 ratio as estimated by h.p.l.c. analysis of the stable hydrolysis products. Formation of diolepoxides was dependent on cell number and the concentration of BP-7,8-diol. Incubation in the presence of the PGH synthase substrate, 20:4 or the inhibitor, indomethacin did not alter the total formation or the ratio of diolepoxides. However, the addition of butylated hydroxyanisole (1 .mu.M) an inhibitor of peroxyl radical dependent-metabolism significantly inhibited diolepoxide formation. The time course for the formation of the anti-diolepoxide and lipid peroxidation, measured as malondialdehyde was determined. The results suggest an excellent correlation between peroxyl radical and diolepoxide formation. Pretreatment of mice with the cytochrome P-450 inducer, .beta.-naphthoflavone greatly altered the metabolism of (+)-BP-7,8-diol by keratinocytes. The major metabolite was the syn-diolepoxide with significant formation of two unknown metabolites. Pretreatment of mice with BP-7,8-diol did not induce aryl hydrocarbon hydroxylase activity but did increase the yield of syn-diolexide formed from labeled (+)-BP-7,8-diol by 1.5-fold. Our results suggest that peroxyl radical-mediated metabolism is primarily responsible for the oxidation of (+)-BP-7,8-diol in control animals while the cytochrome P-450 system is primarily responsible for oxidation in animals pretreated with inducers.