Mar. 1, 2002 MANHATTAN - When something is broken, you may first have to find out how it functions properly to fix it. A Kansas State University researcher is using that idea to see what is wrong or different in animals with diabetes versus those that are normal.
Thomas Schermerhorn, assistant professor of clinical sciences, is involved in research that may be applied to diabetes in dogs and cats, as well as humans.
"We know what goes wrong in diabetes, but we don't know why it goes wrong. Our approach looks at what is normal and compares that to an abnormal cell to find out where the problem is," Schermerhorn said.
Schermerhorn's research focuses on the functions of the beta cell, the cell in the pancreas that secretes insulin. There are thousands of beta cells, each one with tiny granules containing small amounts of insulin. The granules go to the cell membrane and stay there until receiving the proper stimulus, Schermerhorn said.
"Each granule has a tiny amount of insulin, each one secreting insulin resulting in a normal response after eating a meal. This lowers blood sugar and keeps it under control," Schermerhorn said.
The beta cells Schermerhorn studies are altered so they are capable of reproducing outside the body yet can still secrete insulin. These cells act exactly like beta cells that live inside normal animals and humans, Schermerhorn said.
Schermerhorn began by looking at inhibitors of insulin and found that once the beta cell was stimulated to secrete insulin, it could then be modified by inhibitors. The inhibitors tend to decrease cell response to glucose, the principal nutrient in a diet that stimulates secretion.
Norepinephrine, an inhibitor sometimes called noradrenaline, can inhibit secretion profoundly and has direct effects on the proteins in the final stage of granule release, Schermerhorn said.
"Norepinephrine somehow alters or impairs three crucial proteins from coming together. This either disables the granule from being secreted, or prevents the granule from coming to the membrane and forming a protein complex," Schermerhorn said.
Diabetes is the second most common endocrine problem of older cats and one of the top three endocrine problems of older dogs.
Weight loss, excessive water consumption and excessive urination are common symptoms in dogs or cats indicating they may need to be tested for diabetes, Schermerhorn said.
"Usually, the dog or cat maintains an excellent appetite although they do not gain weight, but instead they may lose weight," Schermerhorn said.
"We're hoping to use a physiological approach to learn about beta cell function and provide a basis for the study of abnormal beta cell function that might contribute to the development of diabetes," Schermerhorn said.
Schermerhorn's research is in collaboration with Geoffrey Sharp, department of molecular medicine in the College of Veterinary Medicine at Cornell University, and Philine Wangemann, department of anatomy and physiology at K-State's College of Veterinary Medicine.
The research project is funded by a grant from the National Institute of Diabetes, Digestive and Kidney Diseases of the National Institutes of Health.
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