Regonyl

Regonyl
Clinical data
Other names	TX-380; NSC-69588; 17α-Ethynyl-5α-androst-2-en-17β-ol 17β-acetate; 17β-Acetoxy-5α,17α-pregn-2-en-20-yne
Identifiers
	IUPAC name [(5S,8R,9S,10S,13S,14S,17R)-17-ethynyl-10,13-dimethyl-1,4,5,6,7,8,9,11,12,14,15,16-dodecahydrocyclopenta[a]phenanthren-17-yl] acetate;
CAS Number	124-85-6;
PubChem CID	159358;
ChemSpider	140149;
UNII	CBY5520366;
KEGG	C15186;
ChEBI	CHEBI:79703;
CompTox Dashboard (EPA)	DTXSID20924673 ;
Chemical and physical data
Formula	C23H32O2
Molar mass	340.507 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES CC(=O)O[C@]1(CC[C@@H]2[C@@]1(CC[C@H]3[C@H]2CC[C@@H]4[C@@]3(CC=CC4)C)C)C#C;
	InChI InChI=1S/C23H32O2/c1-5-23(25-16(2)24)15-12-20-18-10-9-17-8-6-7-13-21(17,3)19(18)11-14-22(20,23)4/h1,6-7,17-20H,8-15H2,2-4H3/t17-,18-,19+,20+,21+,22+,23+/m1/s1; Key:SQRBBVVZRKZEPF-OWNQEUAMSA-N;

Regonyl (developmental code name TX-380), also known as 17α-ethynyl-5α-androst-2-en-17β-ol 17β-acetate, is a steroidal drug described as an antiprogestogen and "antiprolactin" (prolactin inhibitor).^[1]^[2]^[3]^[4]^[5] It was studied for lactation inhibition in bitches.^[4]^[5] It has minimal to no androgenic, estrogenic, or progestogenic activity but is said to strongly inhibit the hypothalamic–pituitary–gonadal axis at central and peripheral levels and to markedly oppose the action of progesterone.^[2]^[3]^[6] However, the antiprogestogenic effects of regonyl do not appear to be due to direct interaction with the progesterone receptor.^[6] The actions of regonyl result in estrus cycle disturbances and impaired ovulation.^[2] Regonyl was proposed for use in humans, for instance in the treatment of gynecological disorders like endometriosis and benign breast disease, and in hormonal contraception.^[2]