[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 thought to participate in light-dependent functions in the retina and may be involved in the neurobiological effects of melatonin.

[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.

[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.