Featured Research

from universities, journals, and other organizations

Brain Enzyme May Play Key Role In Controlling Appetite And Weight Gain

Date:
December 16, 2008
Source:
Albert Einstein College of Medicine
Summary:
An enzyme in the hypothalamus appears to regulate feeding behavior. Researchers have found that overactivity of a brain enzyme may play a role in preventing weight gain and obesity.

Injection of active p70 S6K1 virus into mediobasal hypothalamus reduces overeating of high fat diets and obesity.
Credit: Albert Einstein College of Medicine

Researchers at Albert Einstein College of Medicine of Yeshiva University have found that overactivity of a brain enzyme may play a role in preventing weight gain and obesity. The findings were reported in Cell Metabolism.

To understand what drives hunger and causes metabolic disease, many scientists have focused on the hypothalamus, an almond-sized structure located deep within the brain that controls body temperature, hunger, and thirst. Specialized nerve cells in the hypothalamus sense whether the body contains adequate amounts of nutrients and stored body fat. The cells then send out signals telling other parts of the brain to adjust food intake, metabolic rates, and physical activity accordingly — keeping the body's caloric intake in balance with calories burned.

To learn more about these nutrient-sensing pathways and how they go awry in metabolic disorders, researchers at Einstein focused on an enzyme called p70 S6 Kinase 1, or S6K, which plays a role in regulating the growth and proliferation of all cells, including nerve cells.

"It turns out that this enzyme, and the pathway it regulates, is nutrient sensitive — that is, S6K activity increases in the presence of carbohydrates and protein," says the study's principal investigator, Gary J. Schwartz, Ph.D., professor of medicine and neuroscience at Einstein. "This led us to believe that S6K might not only be involved in maintaining the structure and function of individual cells, but also in regulating the energy balance of the whole body."

To test this hypothesis, the researchers injected rats with special viruses that selectively raise or lower S6K activity. The viruses were injected directly into the lower-middle, or mediobasal, portion of the hypothalamus, an area rich in nutrient-sensing nerve cells.

"When we raised the activity of the enzyme, we saw reductions in food intake, in body weight, and in production of peptides [small chains of amino acids] that normally stimulate feeding," says Dr. Schwartz. "When we lowered S6K activity, we saw essentially the opposite response."

The way increased S6K activity reduced the rats' food intake is important, says Dr. Schwartz: reducing the average size of meals rather than changing the number of meals over the course of a day. So the animals apparently were sated faster and therefore ate less at every meal.

In another experiment, the researchers tested whether increased S6K activity would protect against the natural tendency of mammals on a high-fat diet to overeat. People deal with all those calories by putting on extra weight and becoming insensitive to insulin — two of the hallmarks of metabolic syndrome, a group of risk factors that raise the risk of heart disease and type 2 diabetes.

When animals on a high-fat diet were given the S6K-enhancing virus, they overate less and gained weight more slowly than control animals, the researchers report. In addition, the virus-enhanced animals had lower body-fat levels and better glucose tolerance than the control group.

Overall, the study shows that S6K acts as a kind of food-sensing thermostat in mammals, increasing or decreasing feeding behavior and metabolism to maintain a normal energy balance. "These findings show that it may be possible to control obesity and other human metabolic disorders by developing drugs that regulate S6K activity," says Dr. Schwartz.

Clιmence Blouet, Ph.D., a postdoctoral fellow at Einstein, is the lead author of the paper. The other co-author is Hiraku Ono, Ph.D., also a postdoctoral fellow at Einstein.


Story Source:

The above story is based on materials provided by Albert Einstein College of Medicine. Note: Materials may be edited for content and length.


Cite This Page:

Albert Einstein College of Medicine. "Brain Enzyme May Play Key Role In Controlling Appetite And Weight Gain." ScienceDaily. ScienceDaily, 16 December 2008. <www.sciencedaily.com/releases/2008/12/081212141845.htm>.
Albert Einstein College of Medicine. (2008, December 16). Brain Enzyme May Play Key Role In Controlling Appetite And Weight Gain. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2008/12/081212141845.htm
Albert Einstein College of Medicine. "Brain Enzyme May Play Key Role In Controlling Appetite And Weight Gain." ScienceDaily. www.sciencedaily.com/releases/2008/12/081212141845.htm (accessed July 31, 2014).

Share This




More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

House Republicans Vote to Sue Obama Over Healthcare Law

House Republicans Vote to Sue Obama Over Healthcare Law

Reuters - US Online Video (July 31, 2014) — The Republican-led House of Representatives votes to sue President Obama, accusing him of overstepping his executive authority in making changes to the Affordable Care Act. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Despite Health Questions, E-Cigs Are Beneficial: Study

Despite Health Questions, E-Cigs Are Beneficial: Study

Newsy (July 31, 2014) — Citing 81 previous studies, new research out of London suggests the benefits of smoking e-cigarettes instead of regular ones outweighs the risks. Video provided by Newsy
Powered by NewsLook.com
Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) — Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) — Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins