Clock genes, pancreatic function, and diabetes

• Disruption of circadian rhythms is associated with glucose intolerance and diabetes.
• The endocrine pancreas has an intrinsic self-sustained clock.
• Clock genes play important roles in the pancreatic β cell function.
• Alterations in pancreatic clock gene expression impair insulin secretion.

Circadian physiology is responsible for the temporal regulation of metabolism to optimize energy homeostasis throughout the day. Disturbances in the light/dark cycle, sleep/wake schedule, or feeding/activity behavior can affect the circadian function of the clocks located in the brain and peripheral tissues. These alterations have been associated with impaired glucose tolerance and type 2 diabetes. Animal models with molecular manipulation of clock genes and genetic studies in humans also support these links. It has been demonstrated that the endocrine pancreas has an intrinsic self-sustained clock, and recent studies have revealed an important role of clock genes in pancreatic β cells, glucose homeostasis, and diabetes.