GPR30 is a transmembrane intracellular estrogen receptor (Revankar et al. 2005). Progestin inhibits growth in breast cancer cells through GPR30. GPR30 has been reported in brain, breast carcinoma, blood, bone marrow, CNS, heart, liver, lung, lymph node, placenta, and spleen. ESTs have been isolated from B-cell/lung/testis, brain, ganglion, heart/melanocyte/uterus, kidney, tonsil, liver/spleen, placenta, and prostate libraries. Ligands: Estrogen (Revankar et al. 2005). Caution: Rat GPR30 is also known as GPR41 and HIA-R.