In vitro activity: Estradiol induces new dendritic spines and synapses on hippocampal CA1 pyramidal cells. Estradiol treatment resulted in a 46% increase in NMDA receptor binding. Estradiol treatment increases NMDA receptor binding in parallel with dendritic spine and synapse density. Estradiol treatment results in increased sensitivity of CA1 pyramidal cells to NMDA receptor-mediated synaptic input and that this increase is well correlated with the estradiol-induced increase in dendritic spine density in the apical dendritic tree of these cells. 17 beta-estradiol is found to reduce Ba2+ entry reversibly via Ca2+ channels in acutely dissociated and cultured neostriatal neurons. 17 alpha-Estradiol also reduces Ba2+ currents but is significantly less effective than 17 beta-estradiol in rat neostriatal neurons. 17 beta-estradiol exerts a dose-dependent inhibition of IL-1-, TNF-, and IL-1 and TNF-induced production of bioassayable IL-6. Estradiol inhibits both TNF-induced IL-6 production and osteoclast development in primary bone cell cultures derived from neonatal murine calvaria.

Cell Assay: With treatment of estradiol, ERβ-specific effects on gene expression have been investigated in three different cell lines lacking expression of endogenous ERα and ERβ, namely U2OS (25), HEK293 (26), and　Hs578T (23) cells. 17 genes of the 76   ERβ-regulated genes were commonly regulated by both ERα and ERβ, suggesting that the transcriptional effects of estradiol via ERα or ERβ are largely distinct in U2OS cells. 95 and 61  genes were identified as ERβ-regulated genes in Hs578T cells and HEK293 cells in a 24-h estradiol treatment, respectively. Only three genes (PTGER4, ENPP2, and DKK1)　commonly regulated in both HEK293 and Hs578T cells, suggesting that ERβ evokes distinct gene responses in different　types of target cells. By using estradiol, new roles of ERβ signaling was established, including protective functions in the epithelial-mesenchymal transition,as well as regulation of cell proliferation in the colon.