Groundhogs May Teach People More About Diabetes and Obesity Than About the Weather

The groundhog is known for its mythic contribution to the field of weather prediction, but researchers at Colorado State University believe the marmots might hold the key to a possible treatment for diabetes.

Gregory Florant, professor of biology at Colorado State, said that groundhogs double their body mass before hibernation each year. This profound weight-gain puts the animals in a state of hyperinsulinemia, a sign of insulin resistance that precedes the development of type 2 diabetes in humans, particularly obese humans. However, unlike people, the marmots do not develop diabetes because they stop eating for seven months and burn their body fat as they hibernate. Florant believes that understanding this process can potentially lead to a diabetes treatment for humans.

"When groundhogs hibernate, something switches off the marmot’s appetite and their brains no longer identify starvation as stressful," said Florant. "Identifying the genes that regulate a groundhog’s appetite during hibernation may be an important step toward identifying a diabetes treatment for humans."

Determining how marmots turn off their appetites is the subject of a study being conducted by Florant and Colorado State biochemist Scott Summers who are funded by the National Institute of Diabetic Digestive and Kidney Diseases, a division of the National Institutes of Health.

Tissue samples taken from the 20 sleeping groundhogs in Florant’s lab are allowing the researchers to identify which genes are active when the groundhog is feeding and which ones are active when hibernating. The tissue samples will also be used to identify the biochemical processes that take place in the groundhog’s fat and muscles before and during hibernation, allowing the researchers to understand how insulin resistance develops in groundhogs and how that might relate to humans.

In previous research, Summers identified the chemical ceramide, produced by fat stored in the body, as a substance that perhaps accounts for the development of insulin resistance in humans.

By studying the groundhog tissue samples, Summers will be able to test his hypothesis that ceramide causes insulin resistance. If proven correct, medications could be developed to prevent ceramide accumulation in the body, lessening or even preventing insulin resistance, and providing new treatments for type 2 diabetes.

Diabetes and obesity affects about 16 million Americans and accounts for approximately 15 percent of all health-care expenditures and totals more than $45 billion in direct medical costs each year in the United States. Eighty percent of type 2 diabetics are also obese. Type 2 diabetes is the most common form of the disease, affecting 90 percent to 95 percent of all diabetics. Although children with the disease typically have type 1 diabetes, the rate of type 2 diabetes and obesity is rapidly rising among young people.