RESUMO
AIM: To investigate the effect of glucocorticoid receptor beta(GR?) on the transcriptional activation function of glucocorticoid receptor alpha(GR?) and elucidate the biological significance of glucocorticoid receptor beta. METHODS: GR? (pRSH-GR?) and GR? responsive reporter gene cat (pMMTV-cat) were cotransfected into human osteosarcoma cell line (HOS-8603). Transient transfectants were treated with dexamethasone and the activity of cat was determined by the method of ELISA. The expression p21 messenger RNA was detected by the method of reverse transcription-polymerase chain reaction. RESULTS: GR? repressed the expression of reporter gene-cat in a dose-dependent manner. The expression of messenger RNA of p21, an endogenous target gene of GR?, was also inhibited by GR?. CONCLUSION: GR? can inhibit the transcriptional activation function of GR?. GR? may be an endogenous inhibitor of GR?.