Potential Use of Luminol-Dependent Chemiluminescence for Estimation of Free Radicals Produced in Hepatic Microsomes and Reconstituted Cytochrome P-450 Systems

摘要

The evaluation of luminol-dependent chemiluminescence(CL)for determination of free radicals generated during the oxidative reactions of microsomal enzymes in microsomes and reconstituted systms has been studied.The results indicated that the CL not only depended on NADPH induction but also on intact cytochrome P-450 enzymes.The light emission signal was strongly scavended by SOD with inhibition rate of 93%.A concentration of 24μmol·L^-1 cadmium acetate and 2.5μmol·L^-1 mercuric chloride also inhibited the signal significantly as compared with the control.The study of CL in detecting free radicals formed by biotransformation of 44 xenobiotics suggested that some of the compounds known as free radicals producing agents by bioactivation increased the light emission in cytochroe P-450 enzyme system,such as carbon tetrachloride,chloroform,tetrachloroethylene etc.,the others forming toxic metabolites by biotransformation induced the CL in some cases,such as carbon disulfide,benzene,methyldursban,methylparathion etc.or decreased the light emission,such as parathion,aniline and polychlorinated byphenyls tc.,and still others whose toxic effects have no relationship with their biotransformation had no influence or an inhibitory effect on the CL,such as aminopyrine,TOCP,and acrylamide.CL in the cytochrome P-450 enzyme system remained unchanged during the biotransformation of carcinogens such as diethylitrosamine,dipropylitrosamine and benzo(a)pyrene as compared with the control.However,3-methylcholanthrene and dimethylnitrosamine had an enhancing effect on the CL,while 2acetylaminofluorene and 2-aminoanthracene showed an inhibition to the signals.