5α-Dihydronandrolone

5α-Dihydronandrolone (also known as 5α-DHN, dihydronandrolone, DHN, 5α-dihydro-19-nortestosterone, or 5α-estran-17β-ol-3-one) is a naturally occurring anabolic–androgenic steroid (AAS) and a 5α-reduced derivative of nandrolone (19-nortestosterone).[1] It is a major metabolite of nandrolone and is formed from it by the actions of the enzyme 5α-reductase analogously to the formation of dihydrotestosterone (DHT) from testosterone.[1][2]

5α-Dihydronandrolone

Clinical data
Other names	Dihydronandrolone; DHN; 5α-DHN; 5α-Dihydro-19-nortestosterone; 5α-Estran-17β-ol-3-one; 19-nor-5α-androstan-17β-ol-3-one
Identifiers
IUPAC name (5S,8R,9R,10S,13S,14S,17S)-17-Hydroxy-13-methyl-2,4,5,6,7,8,9,10,11,12,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3-one
CAS Number	1434-85-1
PubChem CID	94202
ChemSpider	85015
UNII	I0V6O3097Q
ChEMBL	ChEMBL3137999
CompTox Dashboard (EPA)	DTXSID60931866
Chemical and physical data
Formula	C18H28O2
Molar mass	276.420 g·mol^−1
3D model (JSmol)	Interactive image
SMILES C[C@]12CC[C@H]3[C@H]([C@@H]1CC[C@@H]2O)CC[C@@H]4[C@@H]3CCC(=O)C4
InChI InChI=1S/C18H28O2/c1-18-9-8-14-13-5-3-12(19)10-11(13)2-4-15(14)16(18)6-7-17(18)20/h11,13-17,20H,2-10H2,1H3/t11-,13-,14+,15+,16-,17-,18-/m0/s1 Key:RHVBIEJVJWNXBU-PNOKGRBDSA-N

When testosterone is 5α-reduced into DHT, which is a much more potent AAS in comparison, its effects are potentiated on a local level.[1][2] The tissues in which this occurs (i.e., the tissues that express 5α-reductase) are referred to as "androgenic" tissues and include the skin, hair follicles, and prostate gland, among others.[1] The conversion of testosterone into DHT is an important factor in the etiology of a variety of androgen-dependent conditions, including acne, excessive facial/body hair growth, scalp hair loss, prostate enlargement, and prostate cancer.[1] Unlike the case of testosterone and DHT, 5α-DHN is a much weaker agonist of the androgen receptor (AR) than is nandrolone.[1][2][3][4] For this reason, instead of local potentiation in androgenic tissues, there is a local inactivation when nandrolone is converted into 5α-DHN by 5α-reductase in these tissues.[1][2][3] This is thought to be largely or completely responsible for the exceptionally high ratio of anabolic to androgenic effects seen with nandrolone.[1][2]

The combination of nandrolone with a 5α-reductase inhibitor like finasteride or dutasteride will block the conversion of nandrolone into 5α-DHN and, unlike with testosterone and various other AAS, thereby considerably increase the propensity of nandrolone for producing androgenic side effects.[3]

Relative affinities of nandrolone and related steroids at the androgen receptor

Compound	rAR (%)	hAR (%)
Testosterone	38	38
5α-Dihydrotestosterone	77	100
Nandrolone	75	92
5α-Dihydronandrolone	35	50
Ethylestrenol	ND	2
Norethandrolone	ND	22
5α-Dihydronorethandrolone	ND	14
Metribolone	100	110
Sources: See template.

See also

• 19-Norandrosterone
• 19-Noretiocholanolone
• 5α-Dihydronorethandrolone
• 5α-Dihydronorethisterone
• 5α-Dihydrolevonorgestrel
• 5α-Dihydroethisterone

References

1. Kicman AT (June 2008). "Pharmacology of anabolic steroids". British Journal of Pharmacology. 154 (3): 502–21. doi:10.1038/bjp.2008.165. PMC 2439524. PMID 18500378.
2. John A. Thomas (6 December 2012). Drugs, Athletes, and Physical Performance. Springer Science & Business Media. pp. 29–. ISBN 978-1-4684-5499-4.
3. William Llewellyn (2011). Anabolics. Molecular Nutrition Llc. pp. 464–. ISBN 978-0-9828280-1-4.
4. Bergink EW, Janssen PS, Turpijn EW, van der Vies J (June 1985). "Comparison of the receptor binding properties of nandrolone and testosterone under in vitro and in vivo conditions". J. Steroid Biochem. 22 (6): 831–6. doi:10.1016/0022-4731(85)90293-6. PMID 4021486.