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Effects of vitamin E and selenium on antioxidant defense in rat heart
Author(s) -
Scholz R. W.,
Minicucci L. A.,
Reddy C. C.
Publication year - 1997
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549700203451
Subject(s) - tbars , lipid peroxidation , mitochondrion , glutathione , vitamin e , chemistry , glutathione peroxidase , antioxidant , endocrinology , glutathione disulfide , cytosol , biochemistry , selenium deficiency , medicine , selenium , biology , enzyme , organic chemistry
Heart mitochondria, isolated from rats fed diets deficient or supplemented with vitamin E (E) and/or selenium (Se), were subjected to time‐course assays of lipid peroxidation stimulated by ascorbate/ADP/Fe3+. Mitochondria depleted of α‐tocopherol (α‐TH) peroxided rapidly as assessed by formation of thiobarbituric acid reactive substances (TBARS). Formation of TBARS was strongly inhibited in mitochondria from rats fed diets supplemented with E. Selenium deficiency, reduced glutathione (GSH), glutathione disulfide (GSSG) or GSH + GSSG did not affect the course of lipid peroxidation in mitochondria from rats supplemented or deficient in E. Combined E and Se deficiency resulted in significantly lower total (oxidized + reduced) mitochondrial coenzyme Q‐9 (CoQ‐9) concentration compared with control rats supplemented with dietary E and Se. Time‐course changes in mitochondrial α‐TH and total CoQ‐9 during oxidizing conditions were minor in +E rats. Total CoQ‐9 was reduced substantially, however, during the course of lipid peroxidation in mitochondria depleted of α‐TH. Selenium‐dependent glutathione peroxidase (Se‐GSHPx) activity was reduced by approximately 96% in heart cytosol, and to a somewhat lesser extent in mitochondria, by dietary Se deficiency. Non‐Se GSHPx activity was not detected in heart cytosol but was detected in very small amounts in heart mitochondria. Glutathione S‐transferase activity of heart cytosol was decreased in E and/or Se deficiency. The results of these experiments indicate that membrane α‐TH was most effective in inhibiting lipid peroxidation in heart mitochondria.