Estriol

Estriol
Names
	IUPAC name Estra-1,3,5(10)-triene-3,16α,17β-triol
	Systematic IUPAC name (1R,2R,3aS,3bR,9bS,11aS)-11a-Methyl-2,3,3a,3b,4,5,9b,10,11,11a-decahydro-1H-cyclopenta[a]phenanthrene-1,2,7-triol
	Other names Oestriol; E3; Estratriol; Theelol; Trihydroxyestrin; Trihydroxyoestrin; 16α-Hydroxyestradiol
Identifiers
CAS Number	50-27-1; 1306-04-3;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:27974;
ChEMBL	ChEMBL193482;
ChemSpider	5553;
ECHA InfoCard	100.000.021
KEGG	C05141;
PubChem CID	5756;
UNII	FB33469R8E;
CompTox Dashboard (EPA)	DTXSID9022366 ;
	InChI InChI=1S/C18H24O3/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/h3,5,8,13-17,19-21H,2,4,6-7,9H2,1H3/t13-,14-,15+,16-,17+,18+/m1/s1 Key: PROQIPRRNZUXQM-ZXXIGWHRSA-N;
	SMILES C[C@]12CC[C@H]3[C@H]([C@@H]1C[C@H]([C@@H]2O)O)CCC4=C3C=CC(=C4)O;
Properties
Chemical formula	C18H24O3
Molar mass	288.387 g/mol
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Estriol (E3), also spelled oestriol, is a steroid, a weak estrogen, and a minor female sex hormone.^[1]^[2] It is one of three major endogenous estrogens, the others being estradiol and estrone.^[1] Levels of estriol in women who are not pregnant are almost undetectable.^[3] However, during pregnancy, estriol is synthesized in very high quantities by the placenta and is the most produced estrogen in the body by far,^[3]^[4] although circulating levels of estriol are similar to those of other estrogens due to a relatively high rate of metabolism and excretion.^[4]^[5] Relative to estradiol, both estriol and estrone have far weaker activity as estrogens.^[1]

In addition to its role as a natural hormone, estriol is used as a medication, for instance in menopausal hormone therapy; for information on estriol as a medication, see the estriol (medication) article.

^ ^a ^b ^c Kuhl H (August 2005). "Pharmacology of estrogens and progestogens: influence of different routes of administration". Climacteric. 8 (Suppl 1): 3–63. doi:10.1080/13697130500148875. PMID 16112947. S2CID 24616324.
^ Puri (1 January 2005). Textbook Of Biochemistry. Elsevier India. pp. 793–. ISBN 978-81-8147-844-3.
^ ^a ^b Strauss JF, Barbieri RL (13 September 2013). Yen and Jaffe's Reproductive Endocrinology. Elsevier Health Sciences. pp. 256–. ISBN 978-1-4557-2758-2.
^ ^a ^b H. Maurice Goodman (14 March 2003). Basic Medical Endocrinology. Academic Press. pp. 436–. ISBN 978-0-08-048836-3.
^ Cite error: The named reference (Prof.)2001 was invoked but never defined (see the help page).

[pmid16112947-1] Kuhl H (August 2005). "Pharmacology of estrogens and progestogens: influence of different routes of administration". Climacteric. 8 (Suppl 1): 3–63. doi:10.1080/13697130500148875. PMID 16112947. S2CID 24616324.

[Puri2005-2] Puri (1 January 2005). Textbook Of Biochemistry. Elsevier India. pp. 793–. ISBN 978-81-8147-844-3.

[IIIBarbieri2013-3] Strauss JF, Barbieri RL (13 September 2013). Yen and Jaffe's Reproductive Endocrinology. Elsevier Health Sciences. pp. 256–. ISBN 978-1-4557-2758-2.

[Goodman2003-4] H. Maurice Goodman (14 March 2003). Basic Medical Endocrinology. Academic Press. pp. 436–. ISBN 978-0-08-048836-3.

[(Prof.)2001-5] Cite error: The named reference (Prof.)2001 was invoked but never defined (see the help page).

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