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 receptors¹. 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 activation².

For many years, LHR was thought to be localized strictly to gonadal cells. In the testes, the LHR is thought to be restricted to Leydig cells. In the ovary, expression of the LHR occurs in theca cells, interstitial cells, differentiated granulosa cells, and luteal cells³. There is increasing evidence that LHR may be present in extragonadal tissues such as:  uterus, female reproductive tract tissues, sperm, seminal vesicles, prostate, skin, breast cell lines, lactating mammary gland, adrenals, neural retina, neuroendocrine cells, and brain⁴.

Mutations in the LH receptor have a strong impact on the male phenotype. Activating mutations of the LH receptor leads to male-limited pseudoprecocious puberty, whereas inactivating mutations result in male pseudohermaphroditism⁴.