The G protein-coupled estrogen receptor (GPER, nomenclature as agreed by the NC-IUPHAR Subcommittee on [26]) was identified following observations of estrogen-evoked cyclic AMP signalling in breast cancer cells [2], which mirrored differential expression an orphan 7-transmembrane GPR30 [6]. There are both cell-surface and intracellular GPER [29, 34]. Selective agonist/ antagonists for have been...