Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Brain Chemical Boosts Body Heat, Aids in Calorie Burn

07.07.2010
New findings by UT Southwestern Medical Center researchers suggest that an enzyme in the brain known as PI3 kinase might control the increased generation of body heat that helps burn off excess calories after eating a high-fat meal.

The increase in energy expenditure, called a thermogenic response, burns calories even in the absence of exercise, so understanding how it is regulated could aid efforts to combat obesity, said Dr. Joel Elmquist, professor of internal medicine, psychiatry and pharmacology at UT Southwestern and co-senior author of the mouse study, which appears online and in the current issue of Cell Metabolism.

“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,” said Dr. Elmquist, adding that the physical activity levels of the mice with reduced PI3 kinase did not change. “These mice were more susceptible to diet-induced obesity.”

It’s still unclear whether the findings in mice are translatable to humans, because one of the tissues that mediates the thermogenic response is brown adipose tissue, a type of fat uncommon 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. Recent studies have suggested that humans do have brown fat, which may have physiological importance,” Dr. 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.”

Prior research both in mice and in humans has shown that acute exposure to too many calories causes the body to temporarily increase energy expenditure, burning more energy in an effort to use up those excess calories.

For the current study, UT Southwestern researchers generated a type of mouse that has reduced PI3 kinase activity in neurons located in the ventromedial hypothalamus, a small region of the brain known to influence food intake and body weight. The goal was to determine how PI3 kinase signaling in these neurons affects energy balance.

Dr. Yong Xu, instructor of internal medicine at UT Southwestern and co-lead author of the study, said the findings were dramatic but raise many additional questions.

“The animals in this study developed obesity mainly because they didn’t produce enough heat after eating, not because the animals ate more or were less active,” Dr. Xu said. “A better understanding of this pathway in the brain might lead to ways to activate or enhance it, and perhaps result in a way to combat obesity not by prohibiting eating or increasing physical activity, but by generating more energy expenditure.”

The team also found that the neurons in the ventromedial hypothalamus need PI3K in order to mediate the effects of the hormone leptin, which has been shown to activate this pathway and which is known to be a key player in regulating energy use in the body. Other hormones, including estrogen, might also be involved in regulating the system, the researchers said.

The next step, Dr. Elmquist said, is to identify more precisely the relationship between PI3 kinase-expressing neurons and fat-burning, as well as to characterize better the role of leptin and other hormones in the process.

Other UT Southwestern researchers involved in the study were Dr. Makoto Fukuda, instructor of internal medicine; Dr. Laurent Gautron, assistant instructor of internal medicine; Drs. Jong-Woo Sohn and Ki-Woo Kim, postdoctoral research fellows in internal medicine; Charlotte Lee, senior research scientist; Danielle Lauzon, research assistant; Dr. Jeffrey Zigman, assistant professor of internal medicine and psychiatry; Michele Choi, former research assistant in internal medicine; and Dr. Jennifer Hill, co-lead author and former instructor of internal medicine.

Researchers from Harvard Medical School, Beth Israel Deaconess Medical Center, the Dana-Farber Cancer Institute and the University of Toledo also contributed to the study. Dr. Jean Zhao of Harvard and the Dana-Farber Cancer Institute was co-senior author.

The study was funded by the National Institutes of Health, the Canadian Institutes of Health Research, the V Foundation for Cancer Research, the American Diabetes Association and the Richard and Susan Smith Family Foundation.

Visit http://www.utsouthwestern.org/nutrition to learn more about clinical services in nutrition at UT Southwestern.

Kristen Holland Shear | Newswise Science News
Further information:
http://www.utsouthwestern.org/nutrition

More articles from Health and Medicine:

nachricht Why might reading make myopic?
18.07.2018 | Universitätsklinikum Tübingen

nachricht Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>