AL 082D06 (D06) exhibits specific binding to the glucocorticoid receptor (GR) with high affinity in the nanomolar range. It reduces transcriptional activation in a dose-dependent manner from the MMTV:Luc reporter when stimulated with DEX at half-maximal concentrations. AL 082D06 antagonizes activity across various glucocorticoid-responsive promoter-reporter systems, including the 3-kb TAT promoter and simpler promoters with glucocorticoid response element (GRE) sequences. It competes for binding with 3H-Dex on GR expressed in baculovirus systems, also showing nanomolar affinity. AL 082D06 does not bind to other intracellular receptors like AR, ER, PR, and MR in binding assays with affinities exceeding 2500 nM. Furthermore, it does not activate progesterone, androgen, mineralocorticoid, retinoid, glucocorticoid, or estrogen receptors, demonstrating high efficacy in antagonizing GR activity compared to its much weaker effects on other steroid receptors^[1].