Marmots can teach us about obesity

Jun 02, 2010

A nutrient that's common to all living things can make hibernating marmots hungry - a breakthrough that could help scientists understand human obesity and eating disorders, according to a new study by a Colorado State University biologist.

The study appears in the current issue of the .

Professor Greg Florant discovered he could slowly release a molecule called AICAR into yellow-bellied marmots that activates a neurological pathway driving food intake and stimulates appetite. The pathway, which shuts down during hibernation, relies on an important balance between two energy molecules - ATP and AMP. The lower the ratio between the two cellular molecules, the lower the energy in the cell and the more the appetite is stimulated.

Without this artificial stimulation, awake, hibernating marmots do not eat - even when researchers place food in front of them.

"The experimental group started to feed because they thought they had this energy deficit," Florant said. "Then when the pumps dispensing the molecule finally stopped, the animals went right back into hibernation. That suggests to us that the animals are still sensing energy levels within cells during the hibernation period."

Tissue samples taken from marmots in Florant's lab allow researchers to identify biochemical processes and genes that are active during hibernation - as opposed to genes that are active when they're feeding or engaging in other behaviors.

The American Physiological Society has called hibernators such as marmots, bears, woodchucks, hedgehogs and lemurs "medical marvels" because they can turn off their appetites and slow their breathing to a point that would be lethal to other animals.

Marmots typically hibernate for as many as six or seven months.

"You can't eat if you're asleep," Florant said. "We've discovered that perhaps nutrients within the brain, such as , can alter the food intake pathway, which normally shuts down when marmots hibernate. The perceived drop in energy nutrients (i.e. low ATP) makes the animals think they've got an energy deficit and want to eat."

Florant said he'll conduct additional research this summer to determine whether the reverse is true: Can he stop the animals from eating when they're not hibernating?

His team will also identify neurons in the particular areas of the hypothalamus that are involved in food intake in animals. The hypothalamus is one of the master regulator areas of the brain and controls such activities as , sex and temperature regulation.

"We know which neurons are driving this process," he said. "We're just trying to identify them within the marmot and distinguish what's different about the neurons in a marmot compared to a rat or other animal that does not go into hibernation."

Explore further: Noted researchers warn that biomedical research system in US is unsustainable

More information: The full paper is available at http://jeb.biologists.org/cgi/reprint/213/12/2031.

Provided by Colorado State University

4.8 /5 (4 votes)

Related Stories

Climate change might affect hibernation

Feb 05, 2008

A U.S. study suggested global warning and its associated environmental changes could affect the survival of hibernating species, such as ground squirrels.

Marmots are returned to the Dolomites

Jun 05, 2006

Twenty pairs of marmots -- Europe's version of the U.S.'s groundhog -- have been reintroduced into Italy's National Park of the Belluno Dolomites.

Breaks in hibernation help fight bugs

Aug 16, 2006

U.S. scientists say a habit in some animals to periodically awake during hibernation might be an evolutionary mechanism to fight bacterial infection.

Appetite – it’s a brain thing

Sep 07, 2006

The regulation of body weight and energy balance in animals depends on the central nervous system capacity to read the body’s metabolic state and respond accordingly. But how does the brain process and integrate information ...

Japanese scientists study hibernation

Apr 07, 2006

Japanese researchers say their discovery of a possible hibernation hormone in certain animals' brains may unlock the mystery behind that dormant state.

Scientists study excess fat in chickens

Jan 30, 2008

Obesity is a problem for many American consumers—and now even chickens are getting fat. As a result,scientists have been looking for ways to help growers efficiently produce chickens of optimal weight while minimizing excess ...

Recommended for you

Deadly human pathogen Cryptococcus fully sequenced

8 hours ago

Within each strand of DNA lies the blueprint for building an organism, along with the keys to its evolution and survival. These genetic instructions can give valuable insight into why pathogens like Cryptococcus ne ...

User comments : 0

More news stories

Deadly human pathogen Cryptococcus fully sequenced

Within each strand of DNA lies the blueprint for building an organism, along with the keys to its evolution and survival. These genetic instructions can give valuable insight into why pathogens like Cryptococcus ne ...

Biologists help solve fungi mysteries

(Phys.org) —A new genetic analysis revealing the previously unknown biodiversity and distribution of thousands of fungi in North America might also reveal a previously underappreciated contributor to climate ...

Better thermal-imaging lens from waste sulfur

Sulfur left over from refining fossil fuels can be transformed into cheap, lightweight, plastic lenses for infrared devices, including night-vision goggles, a University of Arizona-led international team ...

Hackathon team's GoogolPlex gives Siri extra powers

(Phys.org) —Four freshmen at the University of Pennsylvania have taken Apple's personal assistant Siri to behave as a graduate-level executive assistant which, when asked, is capable of adjusting the temperature ...

Chronic inflammation linked to 'high-grade' prostate cancer

Men who show signs of chronic inflammation in non-cancerous prostate tissue may have nearly twice the risk of actually having prostate cancer than those with no inflammation, according to results of a new study led by researchers ...