17α-Epiestriol, or simply 17-epiestriol, also known as 16α-hydroxy-17α-estradiol or estra-1,3,5(10)-triene-3,16α,17α-triol, is a minor and weak endogenousestrogen, and the 17α-epimer of estriol (which is 16α-hydroxy-17β-estradiol).[1][2][3] It is formed from 16α-hydroxyestrone.[4][5] In contrast to other endogenous estrogens like estradiol, 17α-epiestriol is a selective agonist of the ERβ.[6] It is described as a relatively weak estrogen, which is in accordance with its relatively low affinity for the ERα.[7] 17α-Epiestriol has been found to be approximately 400-fold more potent than estradiol in inhibiting tumor necrosis factor α (TNFα)-induced vascular cell adhesion molecule 1 (VCAM-1) expressionin vitro.[8]
More information Compound, PRTooltip Progesterone receptor ...
Relative affinities (%) of 17α-epiestriol and related steroids[9][10][11][12]
Values are percentages (%). Reference ligands (100%) were progesterone for the PRTooltip progesterone receptor, testosterone for the ARTooltip androgen receptor, E2 for the ERTooltip estrogen receptor, DEXATooltip dexamethasone for the GRTooltip glucocorticoid receptor, aldosterone for the MRTooltip mineralocorticoid receptor, DHTTooltip dihydrotestosterone for SHBGTooltip sex hormone-binding globulin, and cortisol for CBGTooltip Corticosteroid-binding globulin.