Figure 3.

Melatonin receptors are involved in the regulation of glucose metabolism. Evidence from in vitro and in vivo studies has demonstrated that signaling through melatonin receptors interacts with many facets of glucose metabolism. Within pancreatic islets, melatonin receptors are coupled to signaling pathways, which exert an inhibitory effect on insulin secretion from β-cells and a stimulatory effect on glucagon secretion from α-cells. In peripheral tissues, melatonin receptors appear to positively regulate glucose uptake within skeletal muscle and adipose tissue, and negatively regulate nocturnal glucose production by the liver.