Organ Circadian Clock?

New research shows that each of our organs contains cells with their own circadian-clock genes that help bodily processes operate with maximum efficiency at certain times of day. Each organ operates on its own internal clock, producing enzymes and molecules at different levels depending on the time of day; the brain works to make sure all the clocks are synchronized. Dyssynchrony between the brain and the rest of the organs, or between individual organs, can lead to problems. For example, if the pancreas is out of sync with the liver, insulin production may be too low or too high

In 2005, a team demonstrated that mice with a mutation to a clock gene in the brain's "suprachiasmatic nucleus," the region thought responsible for synchronizing circadian rhythm across the body, had a disrupted feeding pattern.

The mice ate more at all hours of the day, rather than primarily in the evening, when they are typically awake. These mutant mice were obese and had a number of metabolic problems. The researchers found that their behavior influenced the clock genes. Eating a high-fat diet appeared to change the circadian-clock genes in a part of the brain, the liver, and in fat tissue.

Other researchers have looked at the effect of clock genes on the liver. Steve Kay, dean of the biological-sciences division at the University of California, and his colleagues showed that a particular clock gene shuts down excess glucose production in the liver.

A team from the University of Pennsylvania, led by medicine and genetics professor Mitch Lazar, recently found a clock-gene mechanism that reduces the production of fat in the liver at certain times of the day. Such findings suggest manipulating these clock genes could have implications for diabetes or fatty liver disease.

In a case where the rhythm of a particular organ is out of sync with other organs, realignment is more difficult. It may not possible for an individual to control by changing their behaviors, but opens up the possibility of novel ways of treating disease.

I thought this was interesting because it never occurred to me before that individual organs had their own cycles of sleep-wake. This could be used advantageously in many fields if more was known about how each organ functioned at certain times.

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