G-protein coupled receptor 78 (GPR78) was identified based on homology to other GPCR family members. The GPR78 gene encodes an orphan receptor protein that is 363 amino acids in length and contains the typical seven transmembrane domain found in GPCRs. The protein is widely expressed in the mammalian brain including the pituitary and is also found in the placenta. While a ligand for GPR78 has yet to be identified, its expression pattern suggests a potential role in hormone and stress regulation as well as during pregnancy.
