GPR30 Mediates the Fast Effect of Estrogen on Mouse Blastocyst and its Role in Implantation

Our previous work demonstrated that estrogen could rapidly increase intracellular Ca2+ in dormant mouse blastocysts. The purpose of the present study is to investigate the physiological relevance of G protein-coupled receptor 30 (GPR30) in the fast effect of estrogen on mouse blastocyst and in embryo implantation. We used reverse transcription-polymerase chain reaction, immunofluorescence, embryo coculture with Ishikawa uterine epithelial cell line, and embryo transfer technology to detect the expression of GPR30 in mouse embryos and the nongenomic effects of estrogen via GPR30 on blastocyst. We found that GPR30 is expressed in the mouse blastocyst, and its location is mostly consistent with the binding site of estrogen. Both estrogen and GPR30-specific agonist G-1 rapidly increase the intracellular Ca2+ and phospholipase C activation in blastocyst cells, while GPR30-specific antagonist G-15 blocked this effect of estrogen. The pretreatment of G-15 on blastocysts lead to a lower attachment rate and implantation rate. Our data collectively suggested that GPR30 can mediate the fast effect of estrogen on blastocysts and play an important role in embryo implantation.