Type 2 diabetes mellitus is a chronic disease that affects the lives of millions. A type 2 diabetic is unable to properly produce insulin, a hormone that helps glucose enter the cells. As a result, there are high levels of glucose in the bloodstream, which can lead to heart disease, kidney and nerve damage and loss of eyesight. It is well known that some individuals are genetically prone to the disease, and studies have shown that a disrupted sleep/ wake cycle can increase an individual’s chance of developing diabetes. Insulin is secreted in a predictable daily (i.e., circadian) pattern from the pancreas, and a functional biological clock is necessary for proper insulin release. In addition, studies have shown that diabetes affects some the genes which regulate the circadian rhythm, such as period, clock, and bmal1. Given that there is a relationship between circadian rhythms and diabetes, this study investigates the selectively bred TALLYHO/Jng (TH) mice which develop type 2 diabetes at ten weeks of age, mimicking human diabetes symptoms such as hyperglycemia, hyperinsulinemia, obesity, and enlargement of the islets of Langerhans in the pancreas. Eight male TH mice running-wheel turn activity was observed under constant darkness for the course of several weeks. Their free running rhythms were observed pre-and-post onset of diabetes. TH displayed less activity but more frequent bouts per day than the wild type mouse C57BL/6J. TH mice with access to a running-wheel were significantly lighter when compared to studies done by Kim et al, 2006 and Steward et al, 2010, in which TH mice did not have access to running-wheels. Since there is such a weight difference among the mice from different studies, the blood glucose levels were measured for running and non-running mice. Access to running-wheel cage shows to cause long term reduction of diabetes symptoms.
Circadian Rhythms Using a Non-Insulin-Dependent Type-2 Diabetes Mellitus Mouse Model.
Undergraduate Review, 10, 12-18.
Available at: http://vc.bridgew.edu/undergrad_rev/vol10/iss1/8
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