Androgen receptor (UniProt P15207; also known as Dihydrotestosterone receptor, Nuclear receptor subfamily 3 group C member 4) is encoded by the Ar (also known as Andr, Nr3c4, Tfm) gene (Gene ID 24208) in rat species. Androgen receptor (AR) is a hormone-activated transcription regulator that plays important roles in normal prostate development and function, as well as in malignant prostate transformation. The binding of an androgenic hormone (testosterone or dihydrotestosterone) induces a conformational change in AR, resulting in its dissociation from heat schock proteins and subsequent translocation from the cytosol to nucleus, where it dimerizes and mediates either transcription activation or repression in a target gene-specific manner. The androgen insensitivity syndrome (AIS) or testicular feminization (TFM) is caused by a mutation of the androgen receptor gene located on the X chromosome.