How the liver dances to a day/night rhythm

Following the day-night cycle, the liver has its own metabolic rhythm. Using cutting-edge proteomics, scientists at EPFL and Nestlé Institute of Health Sciences have now identified over 500 liver proteins that change in abundance over the course of the day in the cell nucleus, opening a new dimension of metabolism. Biological processes occurring in our bodies are far from static, but instead the rhythm of most of them is dictated by an internal, 24-hour biological metronome called the 'circadian clock'. During each day-night cycle, many physiological processes follow oscillatory waves orchestrated by this clock, allowing them to adapt and anticipate the body's demands at a given time of day. EPFL scientists have now used cutting-edge proteomics to monitor the temporal accumulation of over 5,000 different proteins in the nucleus of mouse liver cells, and have identified over 500 that are connected to the 24-hours cycle. The study, published in Cell Metabolism , is the first in this field in terms of scale and resolution, and has significant implications regarding our understanding of the interconnections between rhythmic metabolism and nutrition. Biology is affected by time Our bodies follow the day-night, or 'diurnal', cycle, by finely tuning metabolic processes to time of day - this is why we can sleep for hours without going hungry through the night but can barely stand eight hours after breakfast, or why jet lag can sometimes cause digestive problems.