Featured Research

from universities, journals, and other organizations

Overproducing Leptin Receptors In Fat Cells May Be Key To Halting Weight Gain

Date:
December 2, 2005
Source:
UT Southwestern Medical Center
Summary:
A new study by researchers at UT Southwestern Medical Center suggests that when fat cells increase in size -- as they do during the development of obesity -- the cells progressively lose receptors for the hormone leptin, a powerful stimulus for fat burning.

Dr. Roger Unger, UT Southwestern researcher, is the senior author of a new obesity study in the Proceedings of the National Academy of Sciences.
Credit: Image courtesy of UT Southwestern Medical Center

A new study by researchers at UT Southwestern Medical Center suggests that when fat cells increase in size -- as they do during the development of obesity -- the cells progressively lose receptors for the hormone leptin, a powerful stimulus for fat burning. Leptin, a hormone produced by the body's fat cells and involved in the regulation of body weight, was first discovered in 1994. It was thought leptin itself would be a key to curing obesity in humans, but the hypothesis did not readily translate into weight loss in obese people. Using mouse models, UT Southwestern researchers have now shown that if enough receptors are present on the fat cells, it is impossible for the cells to store fat and obesity would be blocked.

Related Articles


The new findings, appearing in an upcoming issue of the Proceedings of the National Academy of Sciences and currently available online, bring researchers a step closer to understanding obesity in humans, said Dr. Roger Unger, director of the Touchstone Diabetes Research Center at UT Southwestern and senior author of the study.

"We now think that people with naturally high levels of leptin receptors may not gain weight as rapidly over time as people who have low levels of leptin receptors," said Dr. Unger. "It could explain why some people can eat more and do not gain weight." To test this hypothesis, the UT Southwestern researchers used genetically modified rats in which the leptin receptor remained present in large quantities even during marked overfeeding. In normal mice, the high-fat diet caused massive obesity with enlargement of fat cells to almost three times their normal size. In mice with the forced overexpression of the leptin receptor on their fat cells no obesity occurred, even though they too were fed high-fat, highly caloric diets.

"The fat-storing function of the fat cells requires the disappearance of the leptin receptor," Dr. Unger said. "This is done in order to block the action of the leptin fat cells produce."

May-Yun Wang, lead investigator and instructor of internal medicine at UT Southwestern, said the transgenic mice's high levels of leptin receptors caused all surplus calories to be burned rather than stored.

"They were overfed tremendously and did not get obese. Our control animals were fed the same diet and gained an enormous amount of weight," Dr. Wang said. "If we could prevent the disappearance of leptin receptors in people who overeat, they would likely not gain weight after overeating."

In terms of evolution, researchers reasoned that the ability of leptin receptors to disappear during overeating provided fat cells with a vital mechanism to defend against famine by efficiently storing calories whenever nutrients were abundant. On the other hand, overweight and obese humans, like rodents, have high levels of leptin and low numbers of receptors, Dr. Unger said. The inverse relationship between high leptin and its receptor may explain the failure of most obesity treatment with leptin. The common pattern is a modest weight loss followed by regaining the weight, which may be a function of declining leptin receptor levels.

Currently 50 million Americans suffer from metabolic syndrome -- a disease associated with obesity and encompassing coronary artery disease and type 2 diabetes.

"If we had a pharmacologic way of manipulating the expression of the leptin receptor we might be able to control obesity," Dr. Unger said. "However, by far the best treatment for obesity will always be caloric restriction and regular exercise." Researchers Lelio Orci and Mariella Ravazzola at the University of Geneva Medical School in Switzerland also contributed to the study.



Story Source:

The above story is based on materials provided by UT Southwestern Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

UT Southwestern Medical Center. "Overproducing Leptin Receptors In Fat Cells May Be Key To Halting Weight Gain." ScienceDaily. ScienceDaily, 2 December 2005. <www.sciencedaily.com/releases/2005/12/051202132406.htm>.
UT Southwestern Medical Center. (2005, December 2). Overproducing Leptin Receptors In Fat Cells May Be Key To Halting Weight Gain. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2005/12/051202132406.htm
UT Southwestern Medical Center. "Overproducing Leptin Receptors In Fat Cells May Be Key To Halting Weight Gain." ScienceDaily. www.sciencedaily.com/releases/2005/12/051202132406.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Pet Dogs to Be Used in Anti-Ageing Trial

Pet Dogs to Be Used in Anti-Ageing Trial

Reuters - Innovations Video Online (Nov. 26, 2014) Researchers in the United States are preparing to discover whether a drug commonly used in human organ transplants can extend the lifespan and health quality of pet dogs. Video provided by Reuters
Powered by NewsLook.com
Today's Prostheses Are More Capable Than Ever

Today's Prostheses Are More Capable Than Ever

Newsy (Nov. 26, 2014) Advances in prosthetics are making replacement body parts stronger and more lifelike than they’ve ever been. Video provided by Newsy
Powered by NewsLook.com
From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

Newsy (Nov. 25, 2014) The US FDA is announcing new calorie rules on Tuesday that will require everywhere from theaters to vending machines to include calorie counts. Video provided by Newsy
Powered by NewsLook.com
Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Newsy (Nov. 25, 2014) Need another reason to eat yogurt every day? Researchers now say it could reduce a person's risk of developing type 2 diabetes. Video provided by Newsy
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:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

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