Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fat hormone acts on brain circuit to curb obesity, diabetes

19.01.2005



New research published in the premier issue of Cell Metabolism finds that a single brain region is sufficient for normal control of blood sugar and activity level by the fat hormone leptin. The same region also exerts significant, though more modest, control over leptin’s effects on body weight. The findings in mice provide insight into potential mechanisms underlying type II diabetes and suggest new avenues for treatment, according to the researchers.

Secreted by fat cells, leptin signals the status of the body’s energy content to the brain and is required for normal body weight and glucose balance. Mice lacking leptin develop obesity, diabetes, and inactivity, among other symptoms.

The new results suggest that leptin signaling acts directly on the brain region known as the hypothalamic arcuate nucleus (ARH) to control insulin and glucose levels in the bloodstream, report Joel Elmquist and Bradford Lowell, both of Beth Israel Deaconess Medical Center and Harvard Medical School, and their colleagues. ARH neurons also mediate the majority, if not all, of the hormone’s action on locomotor activity, they found.



Leptin receptors in the ARH accounted for approximately 22 percent of the hormone’s effects on body weight, the group reports, suggesting that other brain regions are also important to this hormonal function.

"As the incidence of obesity and diabetes continues to rise in industrialized countries, a clear understanding of the cellular and neuroanatomic pathways that control energy and glucose balance is critical to the discovery of new methods to prevent or treat these conditions," Elmquist said. "The current findings definitively demonstrate that the hypothalamic arcuate nucleus is required for normal body weight homeostasis and is sufficient to control leptin’s anti-diabetic actions."

Using a novel technique, the researchers unilaterally re-activated leptin receptors in the ARH of mice in which they had otherwise blocked all leptin receptor activity. The ARH had been proposed as an important site of leptin action.

At 12 weeks of age, mice with restored receptor activity had an approximately 22 percent decline in total body weight due to a reduction in fat mass, compared to those lacking active leptin receptors, they found.

Restoration of leptin signaling also remarkably improved glucose homeostasis in the mice. Eight weeks after the treatment, blood glucose levels in the mice were indistinguishable from normal mice of the same age. The restored mice also exhibited significant increases in locomotor activity compared to leptin-deficient mice. Their activity levels were equivalent to that typical of normal mice.

While earlier studies had shown that leptin acts primarily through its effects on the central nervous system, the findings provide important new details about which brain areas mediate each of the fat hormone’s many actions, the researchers said. The results further suggest that deficits in certain regions of the central nervous system might underlie type II diabetes, Elmquist added.

Roberto Coppari, Masumi Ichinose, Charlotte E. Lee, Abigail E. Pullen, Christopher D. Kenny, Robert A. McGovern, Vinsee Tang, Shun M. Liu, Thomas Ludwig, Streamson C. Chua Jr., Bradford B. Lowell, and Joel K. Elmquist: "The hypothalamic arcuate nucleus: A key site for mediating leptin’s effects on glucose homeostasis and locomotor activity"

Heidi Hardman | EurekAlert!
Further information:
http://www.cellmetabolism.org
http://www.cell.com

More articles from Health and Medicine:

nachricht Satellites, airport visibility readings shed light on troops' exposure to air pollution
09.12.2016 | Veterans Affairs Research Communications

nachricht Oxygen can wake up dormant bacteria for antibiotic attacks
08.12.2016 | Penn State

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: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>