In the present study, we observed SEPP1 induction in human cells stably transfected with the ecdysone inducible system (VgEcR-RXR). Due to VgEcR’s glucocorticoid receptor DNA binding domain, as well as evidence of SEPP1 modulation during development and inflammation, we sought to determine if SEPP1 was regulated by the glucocorticoid receptor or the retinoid X receptor. In addition, evidence exists for changes in plasma selenium levels following glucocorticoid administration, with both increases and decreases noted under different sets of conditions (Peretz et al. 1987; Marano et al. 1990; Watanabe et al. 1997). Although the effect of glucocorticoids on selenium levels has not been fully characterized, it is believed that these changes result from redistribution of selenium between tissue and plasma. It is unknown what role SelP may play in this glucocorticoid-induced selenium redistribution. Therefore, an aim of this study was to examine the glucocorticoid responsiveness of the SEPP1 promoter, and we found that the glucocorticoid receptor (GR) inhibits the expression of SEPP1.
