Receptor for glucocorticoids (GC). Has a dual mode of action: as a transcription factor that binds to glucocorticoid response elements (GRE), both for nuclear and mitochondrial DNA, and as a modulator of other transcription factors. Affects inflammatory responses, cellular proliferation and differentiation in target tissues. Involved in chromatin remodeling. Plays a role in rapid mRNA degradation by binding to the 5' UTR of target mRNAs and interacting with PNRC2 in a ligand-dependent manner which recruits the RNA helicase UPF1 and the mRNA-decapping enzyme DCP1A, leading to RNA decay. Could act as a coactivator for STAT5-dependent transcription upon growth hormone (GH) stimulation and could reveal an essential role of hepatic GR in the control of body growth.[Isoform Alpha]: Has transcriptional activation and repression activity. Mediates glucocorticoid-induced apoptosis. Promotes accurate chromosome segregation during mitosis. May act as a tumor suppressor. May play a negative role in adipogenesis through the regulation of lipolytic and antilipogenic gene expression.[Isoform Beta]: Acts as a dominant negative inhibitor of isoform Alpha. Has intrinsic transcriptional activity independent of isoform Alpha when both isoforms are coexpressed. Loses this transcription modulator function on its own. Has no hormone-binding activity. May play a role in controlling glucose metabolism by maintaining insulin sensitivity. Reduces hepatic gluconeogenesis through down-regulation of PEPCK in an isoform Alpha-dependent manner. Directly regulates STAT1 expression in isoform Alpha-independent manner.[Isoform Alpha-2]: Has lower transcriptional activation activity than isoform Alpha. Exerts a dominant negative effect on isoform Alpha trans-repression mechanism.[Isoform GR-P]: Increases activity of isoform Alpha.