Compound

16alpha,17beta-estriol

A hydroxylated metabolite of estradiol or estrone that has a hydroxyl group at C3, 16-alpha, and 17-beta position. Estriol is a major urinary estrogen. During pregnancy, a large amount of estriol is produced by the placenta. Isomers with inversion of the hydroxyl group or groups are called epiestriol.

Definition from MeSH (D004964), National Library of Medicine, read 2026-09-23. NLM revises MeSH; this copy may not reflect its current record.

CHEBI:27974ChEBI

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Structure

2D depiction · 3D model shown

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A generated conformer of 16alpha,17beta-estriol — one low-energy arrangement PubChem computed, not a measured structure. Hydrogens are not drawn; the formula counts them.

Class: Organic compound
Formula: C18H24O3
Mass: 288.387 g/mol
Charge: 0
InChIKey: PROQIPRRNZUXQM-ZXXIGWHRSA-N
SMILES: [H][C@@]12CCc3cc(O)ccc3[C@@]1([H])CC[C@]1(C)[C@@H](O)[C@H](O)C[C@@]21[H]
Look it up: ChEBI PubChem By InChIKey

Identity from ChEBI, geometry from PubChem. Not evidence.

What it touches on the way

Mechanistic reach

6 entities

6 entities reached.

0 reported hops6 assembled from the scaffold

What the reference databases state

Regulatory determinations

LiverTox likelihood score ALiverTox
LiverTox Likelihood Score A — well known, well described and well reported to cause liver injury. Chapter: "Dimethyl Fumarate". Source: LiverTox Master List (NBK571102).
The document·Public Domain (NLM/NIH)·Transcribed, not assessed

Statements

12 statements

12 statements · 2 reference databases · Subject: 16alpha,17beta-estriol · Sources: Human-GEM, Rhea

Order

16alpha-hydroxyestrone is converted to 16alpha,17beta-estriolCompoundHuman-GEM MAR11369Inferred only
16alpha,17beta-estriol is converted to 16alpha,17beta-estriol 16-O-(beta-D-glucuronate)CompoundHuman-GEM MAR07984Inferred only
16alpha,17beta-estriol is converted to 16alpha,17beta-estriol 16-O-(beta-D-glucuronate)CompoundRhea RHEA:52472Inferred only
16alpha,17beta-estriol is converted to 16alpha,17beta-estriol 3-O-(beta-D-glucuronate)CompoundRhea RHEA:52468Inferred only
17beta-estradiol is converted to 16alpha,17beta-estriolCompoundHuman-GEM MAR11368Inferred only
16alpha,17beta-estriol is metabolised by UGT1A1ProteinHuman-GEM MAR07984Inferred only
16alpha,17beta-estriol is metabolised by UGT1A10ProteinRhea RHEA:52468Inferred only
16alpha,17beta-estriol is metabolised by UGT1A10ProteinHuman-GEM MAR07984Inferred only
16alpha,17beta-estriol is metabolised by UGT1A8ProteinHuman-GEM MAR07984Inferred only
16alpha,17beta-estriol is metabolised by UGT2B28ProteinHuman-GEM MAR07984Inferred only
16alpha,17beta-estriol is metabolised by UGT2B4ProteinHuman-GEM MAR07984Inferred only
16alpha,17beta-estriol is metabolised by UGT2B7ProteinRhea RHEA:52472Inferred only

Reactions

10 reactions

16alpha,17beta-estriol16alpha,17beta-estriol
Reaction pageReversibleBalancedcytosol, endoplasmic reticulum
Human-GEM MAR07983CC BY 4.0Reference data
16alpha,17beta-estriol+UDP-alpha-D-glucuronate16alpha,17beta-estriol 16-O-(beta-D-glucuronate)+UDP
Catalysed by UGT2B28 or UGT2B4 or UGT1A1 or UGT1A8 or UGT1A10
Reaction pageLeft to rightBalancedEC 2.4.1.17endoplasmic reticulum
Human-GEM MAR07984CC BY 4.0Reference data
16alpha,17beta-estriol16alpha,17beta-estriol
Reaction pageReversibleBalancedcytosol, extracellular space
Human-GEM MAR09176CC BY 4.0Reference data
16alpha,17beta-estriol
Reaction pageReversibleBalance undeterminableextracellular space
Human-GEM MAR09452CC BY 4.0Reference data
ATP+16alpha,17beta-estriol+waterADP+16alpha,17beta-estriol+proton+phosphate(3-)
Reaction pageLeft to rightBalancedcytosol, extracellular space
Human-GEM MAR10425CC BY 4.0Reference data
17beta-estradiol+proton+NADPH(4-)+dioxygen16alpha,17beta-estriol+water+NADP(3-)
Reaction pageLeft to rightBalancedendoplasmic reticulum
Human-GEM MAR11368CC BY 4.0Reference data
16alpha-hydroxyestrone+proton+NADH(2-)16alpha,17beta-estriol+NAD(+)
Reaction pageLeft to rightBalancedEC 6.2.1.2endoplasmic reticulum
Human-GEM MAR11369CC BY 4.0Reference data
17beta-estradiol+reduced [NADPH--hemoprotein reductase]+dioxygen16alpha,17beta-estriol+oxidized [NADPH--hemoprotein reductase]+water+hydron
Catalysed by CYP3A4 or CYP2C8
Reaction pageLeft to rightBalance undeterminable
Rhea RHEA:47332CC BY 4.0Reference data
16alpha,17beta-estriol+UDP-alpha-D-glucuronate16alpha,17beta-estriol 3-O-(beta-D-glucuronate)+UDP+hydron
Catalysed by UGT1A10
Reaction pageLeft to rightBalanced
Rhea RHEA:52468CC BY 4.0Reference data
16alpha,17beta-estriol+UDP-alpha-D-glucuronate16alpha,17beta-estriol 16-O-(beta-D-glucuronate)+UDP+hydron
Catalysed by UGT2B7
Reaction pageLeft to rightBalanced
Rhea RHEA:52472CC BY 4.0Reference data

Other names

15 names

Resolves to: 16alpha,17beta-estriol

Also called: (16alpha,17beta)-estra-1,3,5(10)-triene-3,16,17-triol(16α,17β)-estra-1,3,5(10)-triene-3,16,17-triol1,3,5(10)-Estratriene-3,16-alpha,17beta-triol16alpha-hydroxyestradiol16α-hydroxyestradiol3,16alpha,17beta-trihydroxy-Delta(1,3,5)-estratriene3,16α,17β-trihydroxy-Δ1,3,5-estratrieneestra-1,3,5(10)-triene-3,16,17-triolESTRIOLoestriolST 18:3;O3trihydroxyestrin
Systematic name: estra-1,3,5(10)-triene-3,16alpha,17beta-triolestra-1,3,5(10)-triene-3,16α,17β-triol
Sold as: Estriel