The glucocorticoid receptor (GR) is a nuclear receptor that mediates the cellular effects of glucocorticoid hormones like cortisol. The GR luciferase reporter vector is designed to study the transcriptional activity of this receptor. The vector contains a GR DNA consensus binding site and TA minimal promoter upstream of a firefly luciferase reporter gene, which can specifically report GR activity while maintaining a low basal level of transcription.