Featured Research

from universities, journals, and other organizations

Obesity creates wimpy rats

Date:
May 10, 2011
Source:
Penn State
Summary:
Obesity appears to impair normal muscle function in rats, an observation that could have significant implications for humans, according to new research.

Obesity appears to impair normal muscle function in rats, an observation that could have significant implications for humans, according to Penn State researchers.

"Our findings demonstrate that obesity involves more than accumulating excess fat and carrying excess weight," said Rudolf J. Schilder, American Physiological Society postdoctoral fellow in physiological genomics, Penn State College of Medicine. "We show that, during the development of obesity, skeletal muscles fail to adjust their molecular composition appropriately to the increasing body weight. Consequently, the muscles of obese mammals are not properly 'tuned' to the higher body weight they carry."

Schilder and his colleagues examined whether normal mammalian skeletal muscle perceives the amount of weight it is carrying, and whether it makes physiological adjustments to compensate for more or less weight. They theorized that this ability of muscle may be affected in obesity, as obese mammals typically suffer from reduced mobility and muscle function.

The study, published in a recent issue of the Journal of Experimental Biology, used both healthy and genetically obese rats to determine how the expression of troponin T -- a gene that codes for a protein essential to muscle function -- varied as rats gained weight.

The research shows that the regulation of troponin T expression in a way appropriate for given body weights is impaired in obese rats.

"These results may explain why muscle strength and locomotion are impaired in obese humans, and hence perhaps why it is so difficult to lose excess weight and recover from obesity," said Schilder.

The researchers first demonstrated that troponin T expression varied with body weight during normal growth. Then they artificially increased the body weight of one group of rats by 30 percent using a custom-made weighted vest. Externally applied weight caused a shift in the muscle troponin T expression, matching that of animals whose actual body weight was 30 percent higher. In contrast, troponin T expression did not respond to a similar increase in body weight in the obese rats.

Troponin T expression was examined in the muscles from a total of 68 rats. Nine were genetically obese, 19 were weight loaded and the rest of the rats served as controls. The weight-loaded rats wore the vests for five days.

"Our study is likely to stimulate a quest to determine the pathways and mechanisms that sense body weight and control muscle molecular composition, as this could ultimately provide new therapeutic approaches to alleviate these obesity-associated problems," said Schilder.

Also working on this research were Scot R. Kimball, professor of cellular and molecular physiology; Leonard S. Jefferson, Evan Pugh Professor of cellular and molecular physiology and chair, both at Penn State College of Medicine; and James H. Marden, professor of biology, Penn State Eberly College of Science.

The National Institutes of Health, the National Science Foundation and the American Physiological Society supported this research.


Story Source:

The above story is based on materials provided by Penn State. Note: Materials may be edited for content and length.


Journal Reference:

  1. R. J. Schilder, S. R. Kimball, J. H. Marden, L. S. Jefferson. Body weight-dependent troponin T alternative splicing is evolutionarily conserved from insects to mammals and is partially impaired in skeletal muscle of obese rats. Journal of Experimental Biology, 2011; 214 (9): 1523 DOI: 10.1242/jeb.051763

Cite This Page:

Penn State. "Obesity creates wimpy rats." ScienceDaily. ScienceDaily, 10 May 2011. <www.sciencedaily.com/releases/2011/05/110509122728.htm>.
Penn State. (2011, May 10). Obesity creates wimpy rats. ScienceDaily. Retrieved August 30, 2014 from www.sciencedaily.com/releases/2011/05/110509122728.htm
Penn State. "Obesity creates wimpy rats." ScienceDaily. www.sciencedaily.com/releases/2011/05/110509122728.htm (accessed August 30, 2014).

Share This




More Health & Medicine News

Saturday, August 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

We've Got Mites Living In Our Faces And So Do You

We've Got Mites Living In Our Faces And So Do You

Newsy (Aug. 30, 2014) A new study suggests 100 percent of adult humans (those over 18 years of age) have Demodex mites living in their faces. Video provided by Newsy
Powered by NewsLook.com
Liberia Continues Fight Against Ebola

Liberia Continues Fight Against Ebola

AFP (Aug. 30, 2014) Authorities in Liberia try to stem the spread of the Ebola epidemic by raising awareness and setting up sanitation units for people to wash their hands. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
California Passes 'yes-Means-Yes' Campus Sexual Assault Bill

California Passes 'yes-Means-Yes' Campus Sexual Assault Bill

Reuters - US Online Video (Aug. 30, 2014) California lawmakers pass a bill requiring universities to adopt "affirmative consent" language in their definitions of consensual sex, part of a nationwide drive to curb sexual assault on campuses. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
3 Things To Know About The Ebola Outbreak's Progression

3 Things To Know About The Ebola Outbreak's Progression

Newsy (Aug. 29, 2014) Here are three things you need to know about the deadly Ebola outbreak's progression this week. 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:
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