CAS number
Jmol-3D images Image 1
Molecular formula C21H34O2
Molar mass 318.49 g mol−1
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)

Pregnanolone (3α-hydroxy-5β-pregnan-20-one or 3α,5β-tetrahydroprogesterone; sometimes abbreviated as 3α,5β-THP), also known as eltanolone (INN), is an endogenous neurosteroid that is biosynthesized from progesterone.[1] It is a positive allosteric modulator of the GABAA receptor,[1] as well as a negative allosteric modulator of the glycine receptor,[2] and is known to have sedative, anxiolytic, anesthetic, and anticonvulsant effects.[1][3][2] 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.[2][4]

See also


  1. ^ a b c Reddy DS (2003). "Pharmacology of endogenous neuroactive steroids". Crit Rev Neurobiol 15 (3-4): 197–234.  
  2. ^ a b c Jürgen Schüttler; Helmut Schwilden (8 January 2008). Modern Anesthetics. Springer Science & Business Media. pp. 278–.  
  3. ^ Carl P, Høgskilde S, Lang-Jensen T, et al. (October 1994). "Pharmacokinetics and pharmacodynamics of eltanolone (pregnanolone), a new steroid intravenous anaesthetic, in humans". Acta Anaesthesiol Scand 38 (7): 734–41.  
  4. ^ Norman Calvey; Norton Williams (21 January 2009). Principles and Practice of Pharmacology for Anaesthetists. John Wiley & Sons. pp. 110–.