Featured Research

from universities, journals, and other organizations

Bears And Hibernation: New Insights Into Metabolism In Extreme Conditions

Date:
May 16, 2008
Source:
University of Barcelona
Summary:
Due to their ability to produce a potent inhibitor of protein degradation, hibernating bears do not lose muscle mass after long periods of hibernation. The team researched for the first time the physiological reasons for an effect that is well known to the scientific community -- the fact that hibernating bears do not lose muscle tissue, only fat. The team studied the physiological response of muscle cells of laboratory rats grown with hibernating bear plasma outside the period of hibernation.

Hibernating bears do not lose muscle mass after long periods of hibernation due to their ability to produce a potent inhibitor of protein degradation, researchers have found.
Credit: iStockphoto/Roger Branch

Due to their ability to produce a potent inhibitor of protein degradation, hibernating bears do not lose muscle mass after long periods of hibernation. This is the main conclusion of the study directed by Professor Josep M. Argilés and co-written by Francisco J. López-Soriano, Gemma Fuster, Sílvia Busquets and Vanessa Almendro of the Cancer Research Group at the Biochemistry and Molecular Biology Department of the University of Barcelona (UB).

Related Articles


The team researches for the first time the physiological reasons for an effect that is well known to the scientific community – the fact that hibernating bears do not lose muscle tissue, only fat. In the experiment, the team studied the physiological response of muscle cells of laboratory rats grown with hibernating bear plasma outside the period of hibernation (from the Ursus arctos in the Aran Valley in the Pyrenees, a protected species since 1973). In the presence of hibernating bear plasma, the proteolytic rate in the rat muscle fell by 40%. "This suggests that the plasma of hibernating bears contains a factor that regulates protein breakdown, blocking this process in the organism," explains Argilés, Professor of Biochemistry and Molecular Biology at the Faculty of Biology.

Why study bears as a physiological model? Hibernation is a characteristic feature of the life cycle of this large mammal and, in the case of the Pyrenean bear, usually lasts from the second half of November until March or April. During hibernation, bears may go for up to three months without food or drink, and reduce their metabolism to adapt to these extreme conditions. What is more, bears have a relatively stable metabolism and conserve their body temperature in these situations.

In general, the destruction of muscle tissue (cachexia) is a sign of metabolic stress, and in humans is associated with pathologies such as cancer or AIDS or with long periods of malnutrition, immobilization and microgravity. The main channels of protein breakdown in cells are lysosomes and proteasomes, which are responsible for approximately 80% of the proteolytic activity. But the mechanisms of protein breakdown are still not well understood. "Compared with our knowledge of protein synthesis, we know very little about the processes of breakdown, especially about regulation. This possible inhibitory effect of hibernating bear plasma may regulate proteolysis in a natural way, which may have a series of implications for treatment," notes Argilés.

In 1993, the Cancer Research Group at the Biochemistry and Molecular Biology Department at the UB was the first to describe the ubiquitin-proteasome system, the proteolytic system involved in muscle mass loss in pathological situations. This system – an enzyme cascade – is the main cell pathway for protein turnover and also participates in key cellular processes such as the cell cycle, DNA repair, and so on. Years after this first discovery, the same team of scientists at the UB has again broken new ground in detecting a possible natural inhibitor of the cellular mechanisms involved in protein metabolism.

The experts are continuing their research to identify the factor that provokes the antiproteolytic effect, a discovery that would open up possibilities for future strategies for treating cachexia. «In many cases, the response to diseases can be found by studying nature», says Argilés, who is also organizing of the World Cachexia Congress to be held in 2009. Santiago Palazón, of the University of Barcelona, and Jesús Fernández, of Barcelona Zoo, also took part in the project published in Clinical Nutrition.


Story Source:

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


Journal Reference:

  1. Josep M. Argilés, Francisco J. López-Soriano, Gemma Fuster, Sílvia Busquets y Vanessa Almendro. Antiproteolytic effects of plasma from hibernating bears: A new approach for muscle wasting therapy? Clinical Nutrition (2007), 26, 658-661 doi: 10.1016/j.clnu.2007.07.003

Cite This Page:

University of Barcelona. "Bears And Hibernation: New Insights Into Metabolism In Extreme Conditions." ScienceDaily. ScienceDaily, 16 May 2008. <www.sciencedaily.com/releases/2008/05/080514082019.htm>.
University of Barcelona. (2008, May 16). Bears And Hibernation: New Insights Into Metabolism In Extreme Conditions. ScienceDaily. Retrieved December 20, 2014 from www.sciencedaily.com/releases/2008/05/080514082019.htm
University of Barcelona. "Bears And Hibernation: New Insights Into Metabolism In Extreme Conditions." ScienceDaily. www.sciencedaily.com/releases/2008/05/080514082019.htm (accessed December 20, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Saturday, December 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) — In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
Monarch Butterflies Descend Upon Mexican Forest During Annual Migration

Monarch Butterflies Descend Upon Mexican Forest During Annual Migration

Reuters - Light News Video Online (Dec. 19, 2014) — Millions of monarch butterflies begin to descend onto Mexico as part of their annual migration south. Rough Cut (no reporter narration) Video provided by Reuters
Powered by NewsLook.com
The Best Protein-Filled Foods to Energize You for the New Year

The Best Protein-Filled Foods to Energize You for the New Year

Buzz60 (Dec. 19, 2014) — The new year is coming and nothing will energize you more for 2015 than protein-filled foods. Fitness and nutrition expert John Basedow (@JohnBasedow) gives his favorite high protein foods that will help you build muscle, lose fat and have endless energy. Video provided by Buzz60
Powered by NewsLook.com
Birds Might Be Better Meteorologists Than Us

Birds Might Be Better Meteorologists Than Us

Newsy (Dec. 19, 2014) — A new study suggests a certain type of bird was able to sense a tornado outbreak that moved through the U.S. a day before it hit. 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

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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