17-Epiestriol is an estrogen metabolite and a selective estrogen receptor ( ER ) β agonist. 17-epiestriol inhibits the mRNA and protein expression of the vascular cell adhesion molecule VCAM-1 induced by tumor necrosis factor α (TNFα). 17-epiestriol also inhibits TNFα-induced VCAM-1 expression and prevents NF-κB migration to the nucleus. 17-Epiestriol also induces the mRNA and protein expression of endothelial nitric oxide synthase.