17α-Alkylated anabolic steroid
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A 17α-alkylated anabolic steroid is a synthetic anabolic–androgenic steroid (AAS) that features an alkyl group, specifically a methyl or ethyl group, at the C17α position. Unlike many other AAS, 17α-alkylated AAS are orally active and do not require intramuscular injection. However, they uniquely possess a high potential for hepatotoxicity, which simultaneously limits their use. In addition, some have a high risk of gynecomastia due to uniquely high estrogenic activity, although this does not apply to 17α-alkylated AAS that are also 4,5α-reduced or 19-demethylated (i.e., that are also dihydrotestosterone (DHT) or nandrolone derivatives, respectively). The prototypical example of a 17α-alkylated AAS is methyltestosterone (17α-methyltestosterone).
Structure-activity relationships
Extension of the C17α alkyl chain longer than an ethyl group abolishes androgenic activity and converts the drug into an antiandrogen, as in topterone (17α-propyltestosterone) and allylestrenol (17α-allyl-3-deketo-19-nortestosterone) (an extended-chain variant of ethylestrenol). Conversely, replacement of the C17α alkyl group with an ethynyl group greatly reduces but does not abolish androgenic activity, as in ethisterone (17α-ethynyltestosterone) and norethisterone (17α-ethynyl-19-nortestosterone).{{cite journal|last1=Saunders|first1=Francis J.|last2=Drill|first2=Victor A.|title=The Myotrophic and Androgenic Effects of 17-Ethyl-19-Nortestosterone and Related Compounds|journal=Endocrinology|volume=58|issue=5|year=1956|pages=567–572|issn=0013-7227|doi=10.1210/endo-58-5-567|pmid=13317831}} Similarly to extension of the C17α alkyl chain, extension of the C17α ethynyl chain abolishes androgenic activity, as with dimethisterone (6α,21-dimethylethisterone). Dienogest, which is antiandrogenic, features extension of the C17α chain in the form of a cyanomethyl group at the C17α position.
List of 17α-alkylated AAS
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; Testosterone derivatives
- Marketed
- Bolasterone
- Calusterone
- Chlorodehydromethyltestosterone (CDMT)
- Fluoxymesterone
- Formebolone
- Metandienone (methandrostenolone)
- Methandriol (methylandrostenediol)
- Methyltestosterone
- Oxymesterone
- Penmesterol (penmestrol)
- Tiomesterone
- Never marketed
- Chlorodehydromethylandrostenediol (CDMA)
- Chloromethylandrostenediol (CMA)
- Enestebol
- Ethyltestosterone
- Hydroxystenozole
- Methylclostebol (chloromethyltestosterone)
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; Dihydrotestosterone derivatives
- Marketed
- Androisoxazole
- Furazabol
- Mebolazine (dimethazine, dymethazine)
- Mestanolone (methylandrostanolone)
- Oxandrolone
- Oxymetholone
- Stanozolol
- Never marketed
- Desoxymethyltestosterone (DMT)
- Methasterone (methyldrostanolone)
- Methyl-1-testosterone (methyl-δ1-DHT)
- Methylepitiostanol
- Methylstenbolone
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; Nandrolone (19-nortestosterone) derivatives
- Marketed
- Ethylestrenol (ethylnandrol)
- Mibolerone
- Norethandrolone (ethylnandrolone, ethylestrenolone)
- Normethandrone (methylestrenolone, normethisterone)
- Propetandrol (propethandrol)
- Never marketed
- Bolenol (ethylnorandrostenol)
- Dimethyltrienolone
- Ethyldienolone
- Methyldienolone
- Methylhydroxynandrolone
- Metribolone (methyltrienolone)
- Norboletone (norbolethone)
- Tetrahydrogestrinone (THG)
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See also
References
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{{Androgens and antiandrogens}}
{{Androgen receptor modulators}}