Pregnanolone

Pregnanolone, also known as eltanolone (INN), as well as 3α,5β-tetrahydroprogesterone (3α,5β-THP) or 3α-hydroxy-5β-pregnan-20-one, is an endogenous neurosteroid that is biosynthesized from progesterone. It is a positive allosteric modulator of the GABA_A receptor, as well as a negative allosteric modulator of the glycine receptor, and is known to have sedative, anxiolytic, anesthetic, and anticonvulsant effects. It was investigated for clinical use as a general anesthetic, but produced unwanted side effects such as convulsions on occasion, and for that reason was never marketed.