EFFECT OF ESTROGENS ON THE OXIDATIVE DAMAGE-INDUCED BY FERRYLMYOGLOBIN

The effect of estrogens, including estrone (E-1), estradiol-17 beta (E -2), estriol (E-3) and 2-hydroxyestradiol (2-OH-E-2), on the oxidative damage induced by ferrylmyoglobin (ferrylMb) was investigated. These estrogens inhibited lipid peroxidation induced by ferrylMb. The abilit y of 2-OH-E-2 to inhibit lipid peroxidation was much greater than the other estrogens. Furthermore, 2-OH-E-2 trapped 2,2'-azobis- (2-amidino propane)-dihydrochloride peroxyl radicals more rapidly, and among thes e estrogens only 2-OH-E-2 reacted with 2,2-diphenyl-1-picrylhydrazyl. These results suggest that the ability of 2-OH-E-2 to inhibit lipid pe roxidation is becaCTuse it scavenges lipid peroxyl and carbon-centered radicals. Estrogens, except for 2-OH-E-2, partially prevented the ina ctivation of alcohol dehydrogenase (ADH) induced by ferrylMb. Of inter est, however, the exposure of sulfhydryl (SH) enzymes to ferrylMb in t he presence of 2-OH-E-2 dramatically increased the inhibition of the e nzyme activity. Ascorbic acid (ASA) and reduced glutathione (GSH) stro ngly inhibited the inactivation of ADH induced by ferrylMb in the pres ence of 2-OH-E-2. During the reaction of ferrylMb with ASA or GSH in t he presence of 2-OH-E-2, large amounts of oxymyoglobin were formed, su ggesting the involvement of the semiquinone from 2-OH-E-2 in the reduc tion of metmyoglobin. Presumably, the semiquinone formed from 2-OH-E-2 oxidizes the SH group of enzymes to facilitate the rapid inactivation of the SH enzymes induced by ferrylMb. (C) 1998 Elsevier Science Ltd. All rights reserved.