LGR4, also known as leucine-rich repeat-containing G protein-coupled receptor 4, is a G protein-coupled receptors (GPCRs). GPCRs are membrane bound proteins that play key roles in a variety of physiologic functions. Members of the leucine-rich GPCR (LGR) family, such as GPR48, have multiple N-terminal leucine-rich repeats (LRRs) and a 7-transmembrane domain. LGR4 is an orphan GPCR reported to be expressed in steroidogenic tissues such as placenta, ovary, testis, adrenal, pancreas, prostate, and thyroid, as well as in spinal cord, stomach, heart, and kidney.