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]
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]
| 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
- ^ a b c d e f g h 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.
- ^ a b c d e John A. Thomas (6 December 2012). Drugs, Athletes, and Physical Performance. Springer Science & Business Media. pp. 29–. ISBN 978-1-4684-5499-4.
- ^ a b c William Llewellyn (2011). Anabolics. Molecular Nutrition Llc. pp. 464–. ISBN 978-0-9828280-1-4.
- ^ 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.
Recent Comments