| The focus of my research is to develop an understanding of the
underlying complications of obesity and diabetes. Birds are a natural model of insulin resistance
syndrome as they have very high blood sugar levels, which can be 5-7 times that of a mammal of
comparable body mass, and are resistant to insulin-mediated glucose uptake into tissues. What is most
intriguing, however, is that they do not exhibit the adverse complications associated with oxidative
stress observed in mammals with high blood sugar. The lack of responsiveness to insulin may be
attributable to the demonstrated lack of an insulin-responsive glucose transporter in avian tissues.
This transporter is typically upregulated in mammals after a meal, or during exercise, to increase
the amount of glucose taken up by the tissue. The use of fatty acids by birds has also been studied
and appears to be their primary source of energy, despite their high blood sugar levels. In mammals,
increased utilization of this substrate can lead to insulin resistance and may also have played a
similar role in birds throughout evolution. As a result of their remarkable ability to prevent high
blood sugar-induced oxidative stress, birds have been regarded as a unique model of aging. Studies
are currently underway to examine the levels of oxidative stress in the vasculature of birds as
increases in mammals result in impaired vascular reactivity. These ongoing studies on avian glucose
handling pathways may offer insight into novel therapies for human pathologies associated with high
blood glucose concentrations. |
