17β-estradiol stimulates arachidonate release from human amnion-like WISH cells through a rapid mechanism involving a membrane receptor

17beta-Estradiol (17beta- E-2) greatly and dose-dependently stimulates [H-3]arachidonic acid (AA) release from the human amnion-like Wistar Institute Susan Hayflick (WISH) cells. This action is abolished by the phospholipase A(2) inhibitor AA-COCF3, significantly reduced by the estrogen receptor (ER) antagonist ICI 182,780, and uninfluenced by cycloheximide. The estradiol-BSA conjugate E(2)coBSA, which binds putative membrane ERs and is unable to enter the cell, also highly stimulates [H-3] AA release from WISH cells, although to a lesser extent compared with 17beta-E-2. The fluorescent conjugate E(2)coBSA-FITC specifically binds to the surface of a subset of intact WISH cells, and labeling intensity appears dose and time dependent. Cell permeabilization results in a dense intracellular staining, mainly in the peripheral cytoplasm. H-150, an antibody against the N terminus of human ERbeta, also labels the plasma membrane of intact WISH cells and the cytoplasm of permeabilized cells. Almost no labeling is observed using ER-21, an antibody against the N terminus of human ERalpha. RT-PCR evidences the presence of mRNA for ERbeta, not for ERalpha. Our data suggest that 17beta-E-2 stimulates [H-3]AA release from WISH cells through an apparently nongenomic pathway and interaction with membrane binding sites. These last are, at least in part, similar if not identical to ERbeta.