[Study of the localization and the concentration of superoxide dismutase in various thyroid disorders]

The localization of Cu/Zn and Mn superoxide dismutase (SOD), which catalyzes the dismutation of superoxide radicals (O2-) to O2 and H2O2, in various thyroid disorders was studied by an immunohistochemical technique in 20% formalin fixed paraffin embedded thin sections using anti-human Cu/Zn and Mn-SOD antibodies. The concentrations of both SODs in those tissues were also measured by a sandwich enzyme immunoassay technique. Cu/Zn SOD was immunocytochemically stained in most of papillary carcinoma, and some of other disorders. In the normal follicular cells it localized in the perinuclear cytoplasm, whereas in the tumor or hyperplastic cells it was in the cytoplasm homogeneously. Mn SOD was strongly stained in papillary carcinoma and papillary growing cells in adenoma and Graves' disease. The concentrations of Cu/Zn and Mn SOD in every thyroid disorder were higher than those in normal thyroid, and it was much higher in the malignant tumors. The ratio of the concentration of Mn SOD against Cu/Zn SOD in the tissues was higher only in papillary carcinoma compared with that in normal thyroid. In conclusion, SOD seems to be relating to the cell proliferation and differentiation in the thyroid since both SODs increased in tumors and hyperplastic disorders, and Cu/Zn SOD changed its localization and Mn SOD existed predominantly in papillary carcinoma or papillary growing cells.