Estradiol 3-glucuronide

Estradiol 3-glucuronide (E2-3G), also known as 17β-estradiol 3-(β-D-glucuronide), is a naturally occurring and endogenous estrogen conjugate.^[1] It is specifically the C3 glucuronide conjugate of estradiol, the major estrogen in the body.^[1] It is formed from estradiol in the liver by UDP-glucuronosyltransferase via attachment of glucuronic acid and is eventually excreted in urine and bile.^[2][3] Similarly to estrogen sulfates like estrone sulfate, estrogen glucuronides have much higher water solubility than do unconjugated estrogens like estradiol.^[3]

Estradiol 3-glucuronide

Names
IUPAC name 17β-Hydroxyestra-1,3,5(10)-trien-3-yl β-D-glucopyranosiduronic acid
Systematic IUPAC name (2S,3S,4S,5R,6S)-3,4,5-Trihydroxy-6-{[(1S,3aS,3bR,9bS,11aS)-1-hydroxy-11a-methyl-2,3,3a,3b,4,5,9b,10,11,11a-decahydro-1H-cyclopenta[a]phenanthren-7-yl]oxy}oxane-2-carboxylic acid
Other names E2-3G; 17β-Estradiol 3-(β-D-glucuronide)
Identifiers
CAS Number	15270-30-1
3D model (JSmol)	Interactive image
ChEBI	CHEBI:36489
ChEMBL	ChEMBL2074591
ChemSpider	389587
KEGG	C05503
PubChem CID	440713
CompTox Dashboard (EPA)	DTXSID60934579
InChI InChI=1S/C24H32O8/c1-24-9-8-14-13-5-3-12(10-11(13)2-4-15(14)16(24)6-7-17(24)25)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: MUOHJTRCBBDUOW-QXYWQCSFSA-N
SMILES C[C@]12CC[C@H]3[C@H]([C@@H]1CC[C@@H]2O)CCC4=C3C=CC(=C4)O[C@H]5[C@@H]([C@H]([C@@H]([C@H](O5)C(=O)O)O)O)O
Properties
Chemical formula	C24H32O8
Molar mass	448.512 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Estrogen glucuronides can be deconjugated into the corresponding free estrogens by β-glucuronidase in tissues that express this enzyme, such as the mammary gland.^[2] As a result, estrogen glucuronides have estrogenic activity via conversion into estrogens.^[2]

Estradiol 3-glucuronide is a positional isomer of estradiol 17β-glucuronide.

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• t
• e

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.

See also

• Catechol estrogen
• Estradiol sulfate
• Estriol glucuronide
• Estriol sulfate
• Estrogen conjugate
• Lipoidal estradiol