17α-Ethynyl-3α-androstanediol


17α-Ethynyl-3α-androstanediol, also known as 17α-ethynyl-5α-androstane-3α,17β-diol, is a synthetic androstane steroid and a 17α-substituted derivative of 3α-androstanediol which was never marketed. It was under development for the treatment of prostate cancer but was discontinued.
17α-Ethynyl-3α-androstanediol itself shows very low affinity for steroid receptors, including the,,,, and, and its mechanism of action is not well-characterized. It produces 5α-dihydroethisterone, a ligand of several steroid hormone receptors, and 17α-ethynyl-3β-androstanediol, an estrogen, as active metabolites. These metabolites may contribute importantly to the biological activity of 17α-ethynyl-3α-androstanediol, with 17α-ethynyl-3α-androstanediol potentially serving as a prodrug.
Analogues of 17α-ethynyl-3α-androstanediol include 17α-ethynyl-3β-androstanediol, ethinylandrostenediol, ethandrostate, ethinylestradiol, ethisterone, and 5α-dihydroethisterone.