The glucocorticoid receptor (GR) or nuclear receptor subfamily 3, group C, member 1 is a ligand-activated transcription factor that binds with high affinity to cortisol and other glucocorticoids. The GR is expressed in almost every cell in the body and regulates either directly or indirectly genes controlling a wide variety of processes including the development, metabolism, and immune response of the organism. The GR protein is encoded by gene NR3C1 on chromosome 5 (5q31).

Two isoforms of the human glucocorticoid receptor (hGR) have been described, hGRa and hGRb.Mutations in the hormone-binding domain of the human glucocorticoid receptor alpha (hGRalpha) gene have been detected in a variety of glucocorticoid resistance syndromes.Mutation detection of the human glucocorticoid receptor alpha gene area coding for the hormone-binding domain by denaturing gradient gel electrophoresis.