Biological Clocks: Nature, Organization and Interactions

Abstract

Probably few domains of medical research have experienced so much interest within such short time frame as the identification and functioning of biological clocks. While circadian clocks are the best-known, very recent research has shown that biological clocks are numerous, closely interacting and, very importantly, that some are conserved from primitive organisms. While the central coordinator is located in the suprachiasmatic nucleus and mainly sensitive to light/darkness, also multiple peripheral clocks exist, which are sensitive to food and local metabolism and involved in both metabolism and vascular physiology work. The whole system works in a remarkably coordinated manner, although peripheral clocks can also work independently from the central clock. It can be seen how hormonal profiles vary physiologically over a 24h period and how disturbances in these processes can deregulate the system and the metabolic homeostasis. Many genes have just been identified, which largely help to understand functioning of the system and how de-synchronization (due in particular to modern lifestyle) can easily perturb it. The fact that essentially all factors known to be causally involved in the cardiometabolic syndrome (insulin resistance, vascular dysfunction) are involved strongly supports the key role clocks and their dysfunction may play in the present worldwide burden of this pathology. In particular it is impressive to note that simply changes in clock synchronization can induce these disorders, without necessarily invoking overeating and/or sedentarity usually considered as culprits.




J Endocrinol Metab. 2011;1(4):159-165
doi: https://doi.org/10.4021/jem44w