The luteinizing hormone receptor (LHR) is a member of the subfamily of glycoprotein hormone receptors within the superfamily of G-protein coupled receptor (GPCR)/seven-transmembrane domain receptors. The LH/CG receptor is comprised of two structurally and functionally distinct domains, extracellular N-terminal exodomain and membrane-embedded endodomain. These two domains can separately be expressed and processed, including folding. The exodomain alone has the high-affinity hormone binding site but is not capable of generating hormonal signal. In contrast, the endodomain alone has the site for receptor activation.