LOCALIZATION OF CU ZN AND MN SUPEROXIDE-DISMUTASE IN VARIOUS THYROID-DISORDERS/

The intracellular localization of Cu/Zn- and Mn-superoxide dismutases (SOD), which catalyze the dismutation of superoxide radicals (O-2(-)) to O-2 and H2O2, was studied in the thyroid tissue of various thyroid disorders by an immunohistochemical technique. The concentrations of b oth SODs in those tissues were measured also by a sandwich enzyme immu noassay technique. Copper/zinc-SOD in thyroid tissues were identified by immunocytochemical staining in most cases of papillary carcinoma an d in some cases of other thyroid disorders. In normal follicular cells this enzyme is localized in the perinuclear cytoplasm, whereas in thy roid tumor or hyperplastic follicular cells it exists homogenously in cytoplasm. Manganese-SOD stained strongly in papillary carcinoma and p apillary-growing cells in the thyroid tissue of adenoma and Graves' di sease. The concentrations of Cu/Zn- and Mn-SOD in thyroid tumor tissue s and hyperplastic follicular disorders were significantly higher than those in normal thyroid tissue when they were compared as a function of protein or deoxyribonucleic acid contents. The ratio of Mn-SOD to C u/Zn-SOD was significantly higher only in papillary carcinoma, except for other thyroid disorders, as compared with that in the normal thyro id. In conclusion, SOD seems to be related to cell proliferation and d ifferentiation in the thyroid follicular cell because Cu/Zn-SOD change s its localization in tumor and hyperplastic follicular cells. and bec ause the Mn-SOD concentration is increased in papillary carcinoma or p apillary-growing cells.