Melatonin receptor 1B

This gene encodes the MT2 protein, one of two high-affinity forms of a receptor for melatonin, the primary hormone secreted by the pineal gland. This gene product is an integral membrane protein that is a G-protein coupled, 7-transmembrane receptor. It is found primarily in the retina and brain; however, this detection requires RT-PCR. It is thought to participate in light-dependent functions in the retina and may be involved in the neurobiological effects of melatonin. == Clinical significance ==

Several studies have identified MTNR1B receptor mutations that are associated with increased average blood sugar level and around a 20 percent elevated risk of developing type 2 diabetes. MTNR1B mRNA is expressed in human islets, and immunocytochemistry confirms that it is primarily localized in beta cells in islets. == Ligands ==

The following MT2R ligands have selectivity over MT1R: • Compound 3d: antagonist with sub-nM affinity • Compound 18f: antagonist and compound 18g partial agonist: sub-nM affinity, >100-fold selectivity over MT1 • Compound 14: antagonist • Compound 13: agonist == See also ==