Melatonin receptor 1B, also known as MTNR1B, is a protein that in humans is encoded by the MTNR1B gene. [5] [6]
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. [5] Besides the brain and retina this receptor is expressed on the bone forming cells where it regulates their function in depositing bone. [7]
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. [8] [9] [10] MTNR1B mRNA is expressed in human islets, and immunocytochemistry confirms that it is primarily localized in beta cells in islets. [9]
The following MT2R ligands have selectivity over MT1R:
This article incorporates text from the United States National Library of Medicine, which is in the public domain.