Steroid receptors belong to the type I receptors of the nuclear receptor family. Main ligands for steroid receptors are steroids such as corticosteroids, estrogens, androgens, and font-weight: bold; margin: 0px; font-family: Verdana, Arial; font-size: medium;">progestagens.
Steroid receptors are localized in the cytoplasm mostly in complexes with heat shock proteins (HSP). Steroid-like compounds can easily pass the cell membrane due to their lipophilic properties and thus reach the receptors. When the ligand binds to the receptor, the receptor undergoes a conformational change and the heat shock proteins come off. Upon binding the receptors translocate to the nucleus, and bind as homodimers to a specific response element (RE). This leads to activation or repression of gene transcription. Steroid receptors thus act as transcription factors.