[Antioxidant system activities and lipid peroxidation in nodal and non-nodal thyroid tissue of patients operated in connection with euthyroid nodular goiter].

The activities of the antioxidant systems (AOS) and lipid peroxidation (LP) were studied in the thyroid (operation material) of patients with euthyroid nodular goiter (in carcinoma, adenoma, colloid goiter tissues as well as in non-nodular adjacent thyroid tissue). Increased activities of superoxide dismutase (SOD, by 101.0 and 125.9%), catalase (by 76.6 and 71.2%), glutathione peroxidase (by 109.6 and 249.2%), glutathione reductase (by 84.6 and 195.9%) and LP aldehyde products (by 148.5 and 120.4%) were found in the adenoma and carcinoma tissues. The increased antioxidant system activity (SOD by 1.62-fold) and LP level by 1.62-1.65--fold in the non-goiter adjacent tissue from these patients indicate toxicity of malignant and non-malignant tumors for the adjacent normal thyroid tissues. Marked activation of oxidative stress (increased SOD activity (by 38.8-40.7%) reduced glutathione (52.4-90.0%) and TBARS concentrations (37.6-52.7%) in the nodal and non-nodal thyroid tissue in patients with multinodular colloid goiter suggest participation of free radical mechanisms in the disturbance of thyrocytes iodine metabolism and development of thyroid nodular pathology.