THYROID-STIMULATING HORMONE AND SELENIUM SUPPLY INTERACT TO REGULATE SELENOENZYME GENE-EXPRESSION IN THYROID-CELLS (FRTL-5) IN CULTURE

In the absence of a sodium selenite supplement, FRTL-5 cells showed a reduced activity of cytosolic glutathione peroxidase (cGSH-Px), a mark er of selenium status, indicating the cells were Se-deficient, Se-defi cient cells showed a 65% reduction in cGSH-Px mRNA abundance but littl e change in abundance of either phospholipid hydroperoxide glutathione peroxidase or type 1 deiodinase (IDI) mRNA. In Se-replete cells incre ased thyroid stimulating hormone (TSH) caused a small decrease in IDI abundance but in Se-deficient cells TSH caused a large increase. The r esults indicate an interaction between TSH and Se status in the regula tion of thyroid selenoenzyme synthesis. (C) 1998 Federation of Europea n Biochemical Societies.