16α-Hydroxyestrone

Chemical compound From Wikipedia, the free encyclopedia

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]

Quick facts Names, Identifiers ...
16α-Hydroxyestrone
Names
IUPAC name
3,16α-Dihydroxyestra-1,3,5(10)-trien-17-one
Systematic IUPAC name
(2R,3aS,3bR,9bS,11aS)-2,7-Dihydroxy-11a-methyl-2,3,3a,3b,4,5,9b,10,11,11a-decahydro-1H-cyclopenta[a]phenanthren-1-one
Other names
Hydroxyestrone; 16-Hydroxyestrone
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.164.941 Edit this at Wikidata
UNII
  • InChI=1S/C18H22O3/c1-18-7-6-13-12-5-3-11(19)8-10(12)2-4-14(13)15(18)9-16(20)17(18)21/h3,5,8,13-16,19-20H,2,4,6-7,9H2,1H3/t13-,14-,15+,16-,18+/m1/s1
  • Oc1ccc2[C@H]3CC[C@]4(C)C([C@@]6C[C@H]4[C@@H]3CCc2c1)=O.O6
Properties
C18H22O3
Molar mass 286.371 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 Â°C [77 Â°F], 100 kPa).
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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]

More information Estrogen, ERTooltip Estrogen receptor RBATooltip relative binding affinity (%) ...
Selected biological properties of endogenous estrogens in rats
EstrogenERTooltip Estrogen receptor RBATooltip relative binding affinity (%)Uterine weight (%)UterotrophyLHTooltip Luteinizing hormone levels (%)SHBGTooltip Sex hormone-binding globulin RBATooltip relative binding affinity (%)
Control–100–100–
Estradiol (E2)100506 ± 20+++12–19100
Estrone (E1)11 ± 8490 ± 22+++?20
Estriol (E3)10 ± 4468 ± 30+++8–183
Estetrol (E4)0.5 ± 0.2?Inactive?1
17α-Estradiol4.2 ± 0.8????
2-Hydroxyestradiol24 ± 7285 ± 8+b31–6128
2-Methoxyestradiol0.05 ± 0.04101Inactive?130
4-Hydroxyestradiol45 ± 12????
4-Methoxyestradiol1.3 ± 0.2260++?9
4-Fluoroestradiola180 ± 43?+++??
2-Hydroxyestrone1.9 ± 0.8130 ± 9Inactive110–1428
2-Methoxyestrone0.01 ± 0.00103 ± 7Inactive95–100120
4-Hydroxyestrone11 ± 4351++21–5035
4-Methoxyestrone0.13 ± 0.04338++65–9212
16α-Hydroxyestrone2.8 ± 1.0552 ± 42+++7–24<0.5
2-Hydroxyestriol0.9 ± 0.3302+b??
2-Methoxyestriol0.01 ± 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 Î¼g/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: [11][12][13][14][15][16][17][18][19]
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