Monday, April 25, 2005

Circadian rhythm and health

I am interested in health matters related to a good night's sleep.

A new report shows that researchers at Northwestern University and the Howard Hughes Medical Institute noticed during studies molecular and behavioral changes in mice that they believe applies to humans. The mice they are interested in have problems with their circadian systems. When there are changes in body fat and metabolic activity in people like there were in the mice, it is called metabolic syndrome, a complex medical problem which can lead to cardiovascular disease and type 2 diabetes.

The study was reported in a press release on www.eurekalert.org by the scientists. They said the mice have defective Clock genes that control daily rhythms in the brain and throughout the body, including sleeping and eating.

The circadian-challenged mice developed high cholesterol, high triglycerides, high blood sugar, low insulin, bloated fat cells, and lipid-engorged liver cells, the report says. The tricky part comes when the researchers determine the relationship to weight gain, as they found some of these changes appeared to be independent of this factor.

The researchers, reporting in Science Magazine's Scienceexpress at www.sciencemag.org/scienceexpress/recent.shtml found changes in the key proteins in the hypothalamic region of the brain that manages feeding, energy balance, and sleep-wake regulation. They believe that the metabolic changes are caused more directly by misregulated genes in various tissues normally controlled by the Clock gene, rather than by the effects of the weight gain.

So where will this new knowledge take researcher Joseph Bass next? Quoting from his press statement, "It's like an orchestra," said Bass. "The tissues important in metabolism have to be conducted properly. But in the Clock mutant, each tissue plays to its own beat, which creates cacophony at the biological level that sets up the animal for obesity and metabolic disregulation."

More study needed.....

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