Clock genes and metabolic disease

1 Department of Medicine, Division of Endocrinology, Metabolism, and Molecular Medicine; and ; 2 Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois Submitted 1 July 2009 ; accepted in final form 30 July 2009 The circadian system is a key integrator of behavior and metabolism that synchronizes physiological processes with the rotation of the Earth on its axis. In mammals, the clock is present not only within the central pacemaker neurons of the hypothalamus, but also within extra-suprachiasmatic nucleus (SCN) regions of brain and nearly all peripheral tissues. Recent evidence suggests that the complex feedback networks that encompass both the circadian and metabolic systems are intimately intertwined and that disruption of either system leads to reciprocal disturbances in the other. We anticipate that improved understanding of the interconnections between the circadian and metabolic networks will open new windows on the treatment of sleep and metabolic disorders, including diabetes mellitus and obesity. metabolic syndrome; circadian rhythms; sirtuins; sleep disorders; diabetes mellitus Address for reprint requests and other correspondence: J. Bass, Northwestern Univ., Pancoe-ENH Pavilion Rm. 4405, 2200 Campus Dr., Evanston, IL 60208 (e-mail: j-bass{at}northwestern.edu ).