Etiocholanolone is an androgenically inactive metabolite of testosterone and androstenedione and the 5β epimer of androsterone .1,2 It increases the frequency of long channel openings and potentiates GABA-induced chloride currents in HEK293 cells expressing rat α1β2γ2L subunit-containing GABAA receptors when used at a concentration of 10 ?M.3 Etiocholanolone is protective against seizures induced by 6 Hz electroshock or pentylenetetrazol (PTZ; ED50s = 76.9 and 139 mg/kg, respectively).4 It is also pyretic in an IL-1-dependent manner, inducing increases in body temperature in rhesus macaques but not squirrel monkeys that lack testosterone and androstenedione metabolizing enzymes.5
1.Chouinard, S., Yueh, M.-F., Tukey, R.H., et al.Inactivation by UDP-glucuronosyltransferase enzymes: The end of androgen signalingJ. Steroid. Biochem. Mol. Biol.109(3-5)247-253(2008) 2.Baulieu, E.-E., and Mauvais-Jarvis, P.Studies on testosterone metabolismJ. Biol. Chem.239(5)1569-1577(1964) 3.Li, P., Bracamontes, J., Katona, B.W., et al.Natural and enantiomeric etiocholanolone interact with distinct sites on the rat α1β2γ2L GABAA receptorMol. Pharmacol.71(6)1582-1590(2007) 4.Kaminski, R.M., Marini, H., Kim, W.-J., et al.Anticonvulsant activity of androsterone and etiocholanoloneEpilepsia46(6)819-827(2005) 5.Steinetz, B.G., Randolph, C., Werner, R., et al.Pyrogenicity of etiocholanolone and interleukin-1 in new and old world monkeysProc. Soc. Exp. Biol. Med.217(4)435-438(1998)