Humans divide their daily behavior into activities (wakefulness) and resting phases (sleep), which differ widely in their metabolic needs. In this context, the circadian cycle has evolved as an autonomous timing system that aligns behavioral patterns with the solar system and supports the body’s functions and coordinating metabolism. Learn more about the topic below.
Metabolism and circadian cycle
Metabolism is the network of biochemical reactions that organisms employ to transform molecules in order to generate structural energy and construction. The fundamental principles of metabolic regulation are highly conserved in all life forms, and metabolic control transcends all aspects of cellular physiology, from the beginning of life to its end. Gross changes in cellular destination as they happen during development and growth, tumorigenesis or aging are accompanied by total rebinding of cellular metabolism. In addition, discrepancies between metabolic requirements and the metabolic capacity of an organism are associated with a wide variety of pathologies, including metabolic syndrome and type 2 diabetes.
How does circadian cycle control occur?
Circadian control is exercised at all levels, from control of cellular metabolism, to the coordination of organ function in the homeotase of blood nutrients and regulation of sleep-wake cycles in the brain. However, not only does the circadian system impose rhythm in metabolic processes, metabolic signals, and states strongly feed the circadian system. In other words, metabolism is not a mere result of circadian regulation, but also provides important information for the circadian clock. This input-output feedback has become essential for adjusting physiology.
Rhythmic regulation of metabolism is present in most organs. Generally, the circadian clock regulates some of the main physiological functions of each organ. For example, in the kidney, the circadian clock modulates blood flow, glomerular filtration rate and excretion of ions and water, controlled to a large degree by the rhythmic expression of membrane transport proteins. In the pancreas, excretion of insulin and glucagon is under circadian control. Equally important is rhythmic synthesis and excretion of hormones and other active molecules in peripheral tissues, conducting metabolic programs. In addition, the gastrointestinal tract exercises all metabolic and endocrine functions in close collaboration with the microbiome, whose composition also follows daytime rhitmicity in sync with the host clock.
Clinical practice
To achieve circadian control of the entire organism, each cell in the body has its own circadian cycle. Therefore, it is controlled by the master clock and gives ritmicity to individual cells and organs. It is important to emphasize that metabolic regulation is not a mere function of circadian system output. Thus, it is a sign of nutrient levels, energy and redox back to cell clocks to enhance circadian rhythm and adapt to the specific needs of the tissue. Thus, there are multiple systemic and molecular mechanisms that connect the circadian clock with metabolism at all levels, from cellular organelles to the whole organism.
referencesBody
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Article: Metabolism and circadian cycle
– Reinke H, Asher G. Crosstalk between metabolism and circadian clocks. Nat Rev Mol Cell Biol
. 2019;20(4):227-241. Doi:10.1038/s41580-018-0096-9
