The formation of a novel free radical metabolite from CCl4 in the perfused rat liver and in vivo.
The formation of a novel free radical metabolite from CCl4 in the perfused rat liver and in vivo.
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DOI：
10.1016/s0021-9258(17)38535-6
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发表时间：
1986-04
期刊：
影响因子：
--
通讯作者：
H. Connor;R. Thurman;M. Galizi;R. Mason
中科院分区：
文献类型：
--
作者：
H. Connor;R. Thurman;M. Galizi;R. Mason
电子自旋共振光谱已被用来监测自由基CCl 4代谢过程中形成的灌注肝脏苯巴比妥治疗的大鼠。同时用自旋捕获苯基N-叔丁基硝酮和12 CCl 4或13 CCl 4灌注肝脏。分析灌注液样品和灌注液和肝脏样品的CHCl 3：CH 3OH浸提液中活性自由基的苯基N-叔丁基硝酮自由基加合物。在有机萃取物中，超精细耦合常数和13 C同位素效应中观察到的ESR光谱表明存在的三氯甲基自由基的自由基加合物。令人惊讶的是，在水性肝灌注液中观察到比苯基N-叔丁基硝酮/CCl.3自由基加合物更强约两个数量级的额外自由基信号。此加合物也检测到ESR在大鼠尿液中2小时后，胃内除了自旋陷阱和四氯化碳。这种自由基加合物具有与二氧化碳阴离子自由基（CO2-）的自由基加合物相同的超精细耦合常数和13 C同位素效应。的耦合常数的pH依赖性的分析产生的CO2-的pK α为2.8。自由基加合物在灌注的肝脏中或化学地形成。四氯化碳被细胞色素P-450还原脱卤转化为CCl.3。三氯甲基自由基与氧反应形成三氯甲基过氧自由基，CCl 3 OO.，其可转化为COCl然后被捕获。这种自由基加合物会水解成羧酸形式，这是光谱检测。或者，二氧化碳阴离子自由基可以通过完全脱氯形成，然后与自旋捕集器反应得到CO2-。自由基加合物。
Electron spin resonance spectroscopy has been used to monitor free radicals formed during CCl4 metabolism by perfused livers from phenobarbital-treated rats. Livers were perfused simultaneously with the spin trap phenyl N-t-butylnitrone and with either 12CCl4 or 13CCl4. Perfusate samples and CHCl3:CH3OH extracts of perfusate and liver samples were analyzed for phenyl N-t-butylnitrone radical adducts of reactive free radicals. In the organic extracts, hyperfine coupling constants and 13C isotope effects observed in the ESR spectra indicated the presence of the radical adduct of the trichloromethyl radical. Surprisingly, an additional free radical signal about two orders of magnitude more intense than that of the phenyl N-t-butylnitrone/CCl.3 radical adduct was observed in the aqueous liver perfusate. This adduct was also detected by ESR in rat urine 2 h after intragastric addition of spin trap and CCl4. This radical adduct had hyperfine coupling constants and 13C isotope effects identical with the radical adduct of the carbon dioxide anion radical (CO2-.). Analysis of the pH dependence of the coupling constants yielded a pK alpha of 2.8 for the CO2-. radical adduct formed either in the perfused liver or chemically. Carbon tetrachloride is converted into CCl.3 by cytochrome P-450 through a reductive dehalogenation. The trichloromethyl free radical reacts with oxygen to form the trichloromethyl peroxyl radical, CCl3OO., which may be converted into .COCl and then trapped. This radical adduct would hydrolyze to the carboxylic acid form, which is detected spectroscopically. Alternatively, the carbon dioxide anion free radical could form through complete dechlorination and then react with the spin trap to give the CO2-. radical adduct directly.