From Our 2010 Archives

Clues for Burning Fat Without Exercise Found in Mice

THURSDAY, July 8 (HealthDay News) -- A brain enzyme that appears to boost body heat in order to burn off excess calories from a high-fat meal has been identified, but because the research was performed in mice, it might not apply to humans.

Learning more about how this enzyme -- PI3 kinase -- boosts calorie burning without exercise (called a thermogenic response) may lead to new ways to fight obesity, according to the research team at the University of Texas Southwestern Medical Center.

"We found that the mice with reduced PI3 kinase activity in specific neurons in the brain gained weight because they were unable to produce this thermogenic response. These mice were more susceptible to diet-induced obesity," study co-senior author Dr. Joel Elmquist, a professor of internal medicine, psychiatry and pharmacology, said in a university news release.

Because the research was conducted in mice, it's unclear whether the findings apply to humans. One of the tissues that plays a role in thermogenic response is brown adipose tissue, a type of fat that isn't common in adult humans.

"Brown adipose tissue is found in babies -- that's why they're so warm -- but it's unclear whether the tissue has the same physiological role in adult humans that it does in rodents," Elmquist said. "What is clear, however, is that specific brain cells and PI3 kinase seem to play a key role in how mice, and potentially humans, respond on a physiological level to a high-fat diet."

The study is published online and in the July 4 print issue of the journal Cell Metabolism.

-- Robert Preidt

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SOURCE: UT Southwestern Medical Center, news release, July 6, 2010