Estradiol glucuronide

Chemical compound From Wikipedia, the free encyclopedia

Estradiol glucuronide

Estradiol glucuronide, or estradiol 17β-D-glucuronide, is a conjugated metabolite of estradiol.[1] It is formed from estradiol in the liver by UDP-glucuronyltransferase via attachment of glucuronic acid and is eventually excreted in the urine by the kidneys.[1] It has much higher water solubility than does estradiol.[1] Glucuronides are the most abundant estrogen conjugates.[1]

Quick Facts Names, Identifiers ...
Estradiol glucuronide
Names
IUPAC name
3-Hydroxyestra-1,3,5(10)-trien-17β-yl β-D-glucopyranosiduronic acid
Systematic IUPAC name
(2S,3S,4S,5R,6R)-3,4,5-Trihydroxy-6-{[(1S,3aS,3bR,9bS,11aS)-7-hydroxy-11a-methyl-2,3,3a,3b,4,5,9b,10,11,11a-decahydro-1H-cyclopenta[a]phenanthren-1-yl]oxy}oxane-2-carboxylic acid
Other names
E217βG; 17β-Estradiol 17β-D-glucuronide; Estra-1,3,5(10)-triene-3,17β-diol 17β-D-glucuronoside
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
KEGG
  • InChI=1S/C24H32O8/c1-24-9-8-14-13-5-3-12(25)10-11(13)2-4-15(14)16(24)6-7-17(24)31-23-20(28)18(26)19(27)21(32-23)22(29)30/h3,5,10,14-21,23,25-28H,2,4,6-9H2,1H3,(H,29,30)/t14-,15-,16+,17+,18+,19+,20-,21+,23-,24+/m1/s1
    Key: MTKNDAQYHASLID-QXYWQCSFSA-N
  • C[C@]12CC[C@H]3[C@H]([C@@H]1CC[C@@H]2O[C@H]4[C@@H]([C@H]([C@@H]([C@H](O4)C(=O)O)O)O)O)CCC5=C3C=CC(=C5)O
Properties
C24H32O8
Molar mass 448.512 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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When exogenous estradiol is administered orally, it is subject to extensive first-pass metabolism (95%) in the intestines and liver.[2][3] A single administered dose of estradiol is absorbed 15% as estrone, 25% as estrone sulfate, 25% as estradiol glucuronide, and 25% as estrone glucuronide.[2] Formation of estrogen glucuronide conjugates is particularly important with oral estradiol as the percentage of estrogen glucuronide conjugates in circulation is much higher with oral ingestion than with parenteral estradiol.[2] Estradiol glucuronide can be converted back into estradiol, and a large circulating pool of estrogen glucuronide and sulfate conjugates serves as a long-lasting reservoir of estradiol that effectively extends its elimination half-life of oral estradiol.[2] In demonstration of the importance of first-pass metabolism and the estrogen conjugate reservoir in the pharmacokinetics of estradiol,[2] the elimination half-life of oral estradiol is 13 to 20 hours[4] whereas with intravenous injection its elimination half-life is only about 1 to 2 hours.[5]

Approximately 7% of estradiol is excreted in the urine as estradiol glucuronide.[6]

Estradiol glucuronide is transported into prostate gland, testis, and breast cells by OATP1A2, OATP1B1, OATP1B3, OATP1C1, and OATP3A1.[7] The ABC transporters MRP2, MRP3, MRP4, and BCRP, as well as several other transporters, have been found to transport estradiol glucuronide out of cells.[7][8]

The circulating concentrations of estrogen glucuronides are generally more than 10-fold lower than those of estrone sulfate, the most abundant estrogen conjugate in the circulation.[8]

Estradiol glucuronide has been identified as an agonist of the G protein-coupled estrogen receptor (GPER), a membrane estrogen receptor.[9] This may be involved in estradiol glucuronide-induced cholestasis.[9]

Estrogen glucuronides can be deglucuronidated into the corresponding free estrogens by β-glucuronidase in tissues that express this enzyme, such as the mammary gland.[10] As a result, estrogen glucuronides have estrogenic activity via conversion into estrogens.[10]

Estradiol glucuronide shows about 300-fold lower potency in activating the estrogen receptors relative to estradiol in vitro.[11]

The positional isomer of estradiol glucuronide, estradiol 3-glucuronide, also occurs as a major endogenous metabolite of estradiol, circulating at two-thirds of the levels of estrone sulfate when it reaches its maximal concentrations just before ovulation and during the peak in estradiol levels that occurs at this time.[12]

More information Estrogen, Other names ...
Affinities and estrogenic potencies of estrogen esters and ethers at the estrogen receptors
Estrogen Other names RBATooltip Relative binding affinity (%)a REP (%)b
ER ERα ERβ
Estradiol E2 100 100 100
Estradiol 3-sulfate E2S; E2-3S  ? 0.02 0.04
Estradiol 3-glucuronide E2-3G  ? 0.02 0.09
Estradiol 17β-glucuronide E2-17G  ? 0.002 0.0002
Estradiol benzoate EB; Estradiol 3-benzoate 10 1.1 0.52
Estradiol 17β-acetate E2-17A 31–45 24  ?
Estradiol diacetate EDA; Estradiol 3,17β-diacetate  ? 0.79  ?
Estradiol propionate EP; Estradiol 17β-propionate 19–26 2.6  ?
Estradiol valerate EV; Estradiol 17β-valerate 2–11 0.04–21  ?
Estradiol cypionate EC; Estradiol 17β-cypionate  ?c 4.0  ?
Estradiol palmitate Estradiol 17β-palmitate 0  ?  ?
Estradiol stearate Estradiol 17β-stearate 0  ?  ?
Estrone E1; 17-Ketoestradiol 11 5.3–38 14
Estrone sulfate E1S; Estrone 3-sulfate 2 0.004 0.002
Estrone glucuronide E1G; Estrone 3-glucuronide  ? <0.001 0.0006
Ethinylestradiol EE; 17α-Ethynylestradiol 100 17–150 129
Mestranol EE 3-methyl ether 1 1.3–8.2 0.16
Quinestrol EE 3-cyclopentyl ether  ? 0.37  ?
Footnotes: a = Relative binding affinities (RBAs) were determined via in-vitro displacement of labeled estradiol from estrogen receptors (ERs) generally of rodent uterine cytosol. Estrogen esters are variably hydrolyzed into estrogens in these systems (shorter ester chain length -> greater rate of hydrolysis) and the ER RBAs of the esters decrease strongly when hydrolysis is prevented. b = Relative estrogenic potencies (REPs) were calculated from half-maximal effective concentrations (EC50) that were determined via in-vitro β‐galactosidase (β-gal) and green fluorescent protein (GFP) production assays in yeast expressing human ERα and human ERβ. Both mammalian cells and yeast have the capacity to hydrolyze estrogen esters. c = The affinities of estradiol cypionate for the ERs are similar to those of estradiol valerate and estradiol benzoate (figure). Sources: See template page.
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More information Estrogen, Structure ...
Structural properties of selected estradiol esters
EstrogenStructureEster(s)Relative
mol. weight
Relative
E2 contentb
log Pc
Position(s)Moiet(ies)TypeLengtha
Estradiol
1.001.004.0
Estradiol acetate
C3Ethanoic acidStraight-chain fatty acid21.150.874.2
Estradiol benzoate
C3Benzoic acidAromatic fatty acid– (~4–5)1.380.724.7
Estradiol dipropionate
C3, C17βPropanoic acid (×2)Straight-chain fatty acid3 (×2)1.410.714.9
Estradiol valerate
C17βPentanoic acidStraight-chain fatty acid51.310.765.6–6.3
Estradiol benzoate butyrate
C3, C17βBenzoic acid, butyric acidMixed fatty acid– (~6, 2)1.640.616.3
Estradiol cypionate
C17βCyclopentylpropanoic acidCyclic fatty acid– (~6)1.460.696.9
Estradiol enanthate
C17βHeptanoic acidStraight-chain fatty acid71.410.716.7–7.3
Estradiol dienanthate
C3, C17βHeptanoic acid (×2)Straight-chain fatty acid7 (×2)1.820.558.1–10.4
Estradiol undecylate
C17βUndecanoic acidStraight-chain fatty acid111.620.629.2–9.8
Estradiol stearate
C17βOctadecanoic acidStraight-chain fatty acid181.980.5112.2–12.4
Estradiol distearate
C3, C17βOctadecanoic acid (×2)Straight-chain fatty acid18 (×2)2.960.3420.2
Estradiol sulfate
C3Sulfuric acidWater-soluble conjugate1.290.770.3–3.8
Estradiol glucuronide
C17βGlucuronic acidWater-soluble conjugate1.650.612.1–2.7
Estramustine phosphated
C3, C17βNormustine, phosphoric acidWater-soluble conjugate1.910.522.9–5.0
Polyestradiol phosphatee
C3–C17βPhosphoric acidWater-soluble conjugate1.23f0.81f2.9g
Footnotes: a = Length of ester in carbon atoms for straight-chain fatty acids or approximate length of ester in carbon atoms for aromatic or cyclic fatty acids. b = Relative estradiol content by weight (i.e., relative estrogenic exposure). c = Experimental or predicted octanol/water partition coefficient (i.e., lipophilicity/hydrophobicity). Retrieved from PubChem, ChemSpider, and DrugBank. d = Also known as estradiol normustine phosphate. e = Polymer of estradiol phosphate (~13 repeat units). f = Relative molecular weight or estradiol content per repeat unit. g = log P of repeat unit (i.e., estradiol phosphate). Sources: See individual articles.
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References

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