16α-Hydroxyestrone

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16α-Hydroxyestrone
16α-Hydroxyestrone.svg
Names
IUPAC name
(8R,9S,13S,14S,16R)-3,16-Dihydroxy-13-methyl-7,8,9,11,12,14,15,16-octahydro-6H-cyclopenta[a]phenanthren-17-one
Other names
Hydroxyestrone; 16-Hydroxyestrone
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.164.941 Edit this at Wikidata
UNII
Properties
C18H22O3
Molar mass 286.371 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

16α-Hydroxyestrone (16α-OH-E1), or hydroxyestrone, also known as estra-1,3,5(10)-triene-3,16α-diol-17-one, is an endogenous steroidal estrogen and a major metabolite of estrone, as well as an intermediate in the biosynthesis of estriol.[1][2] It is a potent estrogen similarly to estrone, and it has been suggested that the ratio of 16α-hydroxyestrone to 2-hydroxyestrone, the latter being much less estrogenic in comparison and even antiestrogenic in the presence of more potent estrogens like estradiol, may be involved in the pathophysiology of breast cancer.[1] Conversely, 16α-hydroxyestrone may help to protect against osteoporosis.[1]

In terms of relative binding affinity (RBA) for the rat uterine estrogen receptor, 16α-hydroxyestrone showed 2.8% of the affinity of estradiol.[3] For comparison, estrone had 11% of the affinity and estriol had 10% of the affinity of estradiol.[3] In contrast to other estrogens, the binding of 16α-hydroxyestrone to the estrogen receptor is reported to be covalent and irreversible.[4][5][6][7] 16α-Hydroxyestrone has been reported to have 25% of the vaginal estrogenic potency of estradiol.[3] The maximal uterotrophic and antigonadotropic effect of 16α-hydroxyestrone was equivalent to those of estradiol and estriol, indicating that 16α-hydroxyestrone is a fully effective estrogen.[3][8] However, 16α-hydroxyestrone was much less potent than estradiol or estrone.[8]

The C3 and C16α diacetate ester of 16α-hydroxyestrone, hydroxyestrone diacetate (brand names Colpoginon, Colpormon, Hormobion, and Hormocervix), has been marketed and used medically as an estrogen in Europe.[9][10]

Selected biological properties of endogenous estrogens in rats
Estrogen ER RBA (%) Uterine weight (%) Uterotrophy LH levels (%) SHBG RBA (%)
Control 100 100
Estradiol 100 506 ± 20 +++ 12–19 100
Estrone 11 ± 8 490 ± 22 +++ ? 20
Estriol 10 ± 4 468 ± 30 +++ 8–18 3
Estetrol 0.5 ± 0.2 ? Inactive ? 1
17α-Estradiol 4.2 ± 0.8 ? ? ? ?
2-Hydroxyestradiol 24 ± 7 285 ± 8 +b 31–61 28
2-Methoxyestradiol 0.05 ± 0.04 101 Inactive ? 130
4-Hydroxyestradiol 45 ± 12 ? ? ? ?
4-Methoxyestradiol 1.3 ± 0.2 260 ++ ? 9
4-Fluoroestradiola 180 ± 43 ? +++ ? ?
2-Hydroxyestrone 1.9 ± 0.8 130 ± 9 Inactive 110–142 8
2-Methoxyestrone 0.01 ± 0.00 103 ± 7 Inactive 95–100 120
4-Hydroxyestrone 11 ± 4 351 ++ 21–50 35
4-Methoxyestrone 0.13 ± 0.04 338 ++ 65–92 12
16α-Hydroxyestrone 2.8 ± 1.0 552 ± 42 +++ 7–24 <0.5
2-Hydroxyestriol 0.9 ± 0.3 302 +b ? ?
2-Methoxyestriol 0.01 ± 0.00 ? Inactive ? 4
Notes: Values are mean ± SD or range. ER RBA = Relative binding affinity to estrogen receptors of rat uterine cytosol. Uterine weight = Percentage change in uterine wet weight of ovariectomized rats after 72 hours with continuous administration of 1 μg/hour via subcutaneously implanted osmotic pumps. LH levels = Luteinizing hormone levels relative to baseline of ovariectomized rats after 24 to 72 hours of continuous administration via subcutaneous implant. Footnotes: a = Synthetic (i.e., not endogenous). b = Atypical uterotrophic effect which plateaus within 48 hours (estradiol's uterotrophy continues linearly up to 72 hours). Sources: See template.

See also[edit]

References[edit]

  1. ^ a b c Rakel D (2012). Integrative Medicine. Elsevier Health Sciences. pp. 338–339. ISBN 978-1-4377-1793-8.
  2. ^ Vitamins and Hormones. Academic Press. 7 September 2005. pp. 282–. ISBN 978-0-08-045978-3.
  3. ^ a b c d Fishman J, Martucci C (September 1980). "Biological properties of 16 alpha-hydroxyestrone: implications in estrogen physiology and pathophysiology". J. Clin. Endocrinol. Metab. 51 (3): 611–5. doi:10.1210/jcem-51-3-611. PMID 7190977.
  4. ^ Oettel M, Schillinger E (6 December 2012). Estrogens and Antiestrogens I: Physiology and Mechanisms of Action of Estrogens and Antiestrogens. Springer Science & Business Media. pp. 252–. ISBN 978-3-642-58616-3.
  5. ^ Swaneck GE, Fishman J (November 1988). "Covalent binding of the endogenous estrogen 16 alpha-hydroxyestrone to estradiol receptor in human breast cancer cells: characterization and intranuclear localization". Proc. Natl. Acad. Sci. U.S.A. 85 (21): 7831–5. doi:10.1073/pnas.85.21.7831. PMC 282290. PMID 3186693.
  6. ^ Zhu BT, Conney AH (January 1998). "Functional role of estrogen metabolism in target cells: review and perspectives". Carcinogenesis. 19 (1): 1–27. doi:10.1093/carcin/19.1.1. PMID 9472688.
  7. ^ Kuhl H (2005). "Pharmacology of estrogens and progestogens: influence of different routes of administration" (PDF). Climacteric. 8 Suppl 1: 3–63. doi:10.1080/13697130500148875. PMID 16112947. S2CID 24616324.
  8. ^ a b Velardo, Joseph Thomas (1964). "The Actions of Steroid Hormones on Estradiol-17β in Uterine Growth and Enzymorphology". Hormonal Steroids Biochemistry, Pharmacology, and Therapeutics. pp. 463–490. doi:10.1016/B978-0-12-395506-7.50065-0. ISBN 9780123955067.
  9. ^ Index Nominum 2000: International Drug Directory. Taylor & Francis. January 2000. pp. 1250–. ISBN 978-3-88763-075-1.
  10. ^ Muller NF, Dessing RP, European Society of Clinical Pharmacy (19 June 1998). European Drug Index: European Drug Registrations (Fourth ed.). CRC Press. pp. 289–. ISBN 978-3-7692-2114-5.