The biological actions of estrogens are mediated by estrogen binding to one of two specific
estrogen receptors (ERs) ERα and ERβ, which belong to the nuclear receptor superfamily, a
family of ligand-regulated transcription factors. ERα and ERβ are products of different genes
and exhibit tissue-and cell-type specific expression. The characterization of mice lacking
ERα, or ERβ, or both has revealed that both receptor subtypes have overlapping but also
unique roles in estrogen-dependent action in vivo. Additionally, ERα and ERβ have different …