Figure 2.

The suprachiasmatic nucleus (SCN) generates endogenous biological rhythms, ensuring that internal physiology is synchronized with the external environment. Under normal conditions, rhythms in glucose and insulin, bile acids, lipids and drug enzymes contribute to homeostatic control of liver physiology. Under conditions of circadian disruption, including shift work, perturbations in these physiological rhythms result in desynchronized timing between SCN and the periphery and are associated with diabetes, obesity, and other symptoms of metabolic syndrome.