Table 1.

Relative binding affinities of ligands to full-length ERα or ERβ

RBA
Ligand ERα ERβ
17β-Estradiol 100 100
4-Hydroxytamoxifen 36 43
Raloxifene 34 76
GW-5638 5 8
STX 4.3E-6 9.0E-6

  • Relative binding affinities (RBA) are expressed as a percentage of the potency of 17β-estradiol. Under the experimental conditions described in Materials and Methods, 17β-estradiol was found to have an IC50 of 5 nm for ERα and 3 nm for ERβ.