Albano E, Cheeseman K H, Tomasi A, Carini R, Dianzani M U, Slater T F
Biochem Pharmacol. 1986 Nov 15;35(22):3955-60. doi: 10.1016/0006-2952(86)90010-9.
Spin traps are increasingly employed in the detection of free radicals in biological systems, including liver microsomes and isolated hepatocytes. Two spin traps phenyl-t-butyl nitrone (PBN) and 4-pyridyl-l-oxide-t-butyl nitrone (4-POBN) have been tested for their effects on hepatocyte viability and mixed-function oxidase activity. High concentration of PBN but not of 4-POBN proved to moderately affect liver cell integrity, without interfering with intracellular ATP or cytochrome P-450 content. PBN also decreased hepatocyte GSH content, probably as the result of its metabolism to benzaldehyde. The two spin traps were found to inhibit aminopyrine demethylase and ethoxycoumarin deethylase activity in hepatocytes and microsomes. At low concentrations (1-5 mM) PBN enhanced aniline hydroxylase while high concentrations of the spin trap inhibited this activity. The inhibition of the monooxygenase system was not caused by damage of microsomal enzymes, but rather by competition with other substrates for the binding to the haemoprotein. The effects of spin traps on mixed function oxidase systems should be taken into account when evaluating the results of spin trapping experiments.
自旋捕获剂越来越多地用于检测生物系统中的自由基，包括肝微粒体和分离的肝细胞。已经测试了两种自旋捕获剂苯基叔丁基硝酮（PBN）和4-吡啶基-1-氧化物-叔丁基硝酮（4-POBN）对肝细胞活力和混合功能氧化酶活性的影响。结果表明，高浓度的PBN（而非4-POBN）会对肝细胞完整性产生中度影响，但不会干扰细胞内ATP或细胞色素P-450的含量。PBN还会降低肝细胞谷胱甘肽（GSH）含量，这可能是其代谢为苯甲醛的结果。研究发现这两种自旋捕获剂会抑制肝细胞和微粒体中的氨基比林脱甲基酶和乙氧基香豆素脱乙基酶活性。在低浓度（1-5 mM）时，PBN会增强苯胺羟化酶活性，而高浓度的自旋捕获剂则会抑制该活性。单加氧酶系统的抑制并非由微粒体酶的损伤引起，而是由于与其他底物竞争与血红素蛋白的结合。在评估自旋捕获实验结果时，应考虑自旋捕获剂对混合功能氧化酶系统的影响。
