Ethisterone

Ethisterone

Clinical data
Trade names	Etherone, Ethisteron, Luteosterone, Lutocyclin, Lutocylol, Pranone, Progesteron lingvalete, Progestoral, Proluton C, Syngestrotabs, Trosinone
ATC code	G03DC04 (WHO)
Identifiers
IUPAC name (8R,9S,10R,13R,14S,17R)-17-Ethynyl-17-hydroxy-10,13-dimethyl-2,6,7,8,9,11,12,14,15,16-decahydro-1H-cyclopenta[a]phenanthren-3-one
Synonyms	Etisteron, Pregnin, Ethindrone, Ethinyltestosterone, Ethynyltestosterone
CAS Number	434-03-7 N
PubChem (CID)	5284557
ChemSpider	4447612 Y
UNII	Verifiedfields = changed P201BVY1MJ Verifiedfields = changed N
ChEBI	CHEBI:34749 N
ChEMBL	CHEMBL241694 Y
ECHA InfoCard	100.006.452
Chemical and physical data
Formula	C21H28O2
Molar mass	312.446 g/mol
3D model (Jmol)	Interactive image
SMILES O=C4\C=C3/[C@]([C@H]2CC[C@]1([C@@H](CC[C@]1(C#C)O)[C@@H]2CC3)C)(C)CC4
InChI InChI=1S/C21H28O2/c1-4-21(23)12-9-18-16-6-5-14-13-15(22)7-10-19(14,2)17(16)8-11-20(18,21)3/h1,13,16-18,23H,5-12H2,2-3H3/t16-,17+,18+,19+,20+,21+/m1/s1 Y Key:CHNXZKVNWQUJIB-CEGNMAFCSA-N Y
NY (what is this?)

Ethisterone (INN, USAN, BAN) (brand names Pranone, Progestoral, Lutocylol, Proluton C, many others), also known as 17α-ethinyltestosterone, pregneninolone, or anhydrohydroxyprogesterone, is a steroidal progestin with androgenic activity which is derived from testosterone and was introduced for medical use in 1939. It was the second progestogen to be marketed (intramuscular progesterone was introduced as Proluton in 1934) and was both the first orally active progestogen and the first progestin (or synthetic progestogen) to be introduced. Although ethisterone has largely been superseded by newer drugs and is now little used, it continues to be available in some countries. Moreover, the 19-nortestosterone progestins, such as norethisterone, are derived from ethisterone and are widely used as hormonal contraceptives and for other indications.

Ethisterone is described as a relatively weak progestogen, similarly to its analogue dimethisterone.

Based on in vitro research, ethisterone and norethisterone are about equipotent in their EC₅₀ values for the androgen receptor (AR), whereas, conversely, norethisterone shows markedly increased potency relative to ethisterone in terms of its EC₅₀ for the progesterone receptor (PR). As such, there is a considerable separation in the ratios of androgenic and progestogenic activity for ethisterone and norethisterone. Moreover, at the larger dosages in which it is used to achieve equivalent progestogenic effect, ethisterone has strong androgenic effects relative to norethisterone and other 19-nortestosterone progestins, and this has limited its clinical use.