Disrupted sleep patterns seem to contribute to the risk of obesity and diabetes, according to numerous studies. Researchers have theorized that disrupted circadian rhythms throw off various hormonal processes in the body that contribute to disease.
This theory is looking stronger all the time, and the mounting evidence bolsters the argument that people should care about their sleep habits. Researchers at UT Southwestern Medical Center in Dallas have found that mice with defective copies of two genes involved in circadian rhythms develop abnormalities in their pancreatic cells that eventually cause problems with the release of insulin.
One gene, the CLOCK gene, operates in many parts of the body to control circadian processes. The other gene, BMAL1, works with the CLOCK protein. In the study, scientists engineered some mice to have defective CLOCK genes in the pancreas and some to lack the BMAL1 gene. They found that mice with the mutant CLOCK gene were defective in releasing insulin. These mice were prone to obesity and other health problems related to liver and metabolic function. The mice lacking the BMAL1 gene in their pancreas had normal body weight and normal circadian patterns but had abnormal blood sugar levels.
The study shows that disruption of these genes only in the pancreas causes early signs of diabetes.
"These results indicate that disruption of the daily clock may contribute to diabetes by impairing the pancreas' ability to deliver insulin," a co-author of the paper, Dr. Joseph Takahashi, said in a news release.
The study was released this week in the journal Nature.