CHANGES IN FREE-RADICAL SCAVENGERS AND LIPID PEROXIDE IN THYROID-GLANDS OF VARIOUS THYROID-DISORDERS

To clarify whether the changes of free radicals and its scavengers are induced by thyroid disorders, we measured levels of free radical scav engers and checked O-2 radical generating systems in tile human thyroi d gland. Thyroid specimens from patients with Graves' disease, follicu lar adenoma, and papillary and follicular carcinomas contained signifi cantly higher concentrations of xanthine oxidase (XOD) and gluthathion e peroxidase (GSH-PX), compared to those in the normal thyroid tissue. Catalase concentration was significantly lower in thyroid specimens f rom patients with Graves' disease and significantly lower in thyroid s pecimens from patients with follicular adenoma, compared to those in t he normal thyroid tissue. Cu/Zn superoxide dismutase (Cu/Zn SOD) conce ntration was significantly lower in the specimens from follicular aden oma and papillary carcinoma and Mn SOD concentration was significantly higher in the specimens from papillary carcinoma than those in the no rmal thyroid tissue. The lipid peroxide concentration, expressed as ma londialdehyde (MDA) concentration, was significantly higher in the spe cimens from papillary carcinoma than those in the normal thyroid tissu e. These findings suggest that the levels of free radicals are increas ed and are scavenged and catalyzed in the thyroid of Graves' disease, whereas free radicals and lipid peroxide are not completely scavenged in papillary carcinoma tissues, suggesting that these substances affec t some role in cell function of thyroid tumors.