Featured Research

from universities, journals, and other organizations

Researcher Discovers Clues To Bear Bone Strength

Date:
December 29, 2003
Source:
Michigan Technological University
Summary:
Inactivity is a prime cause of osteoporosis in most animals, including humans. A notable exception is the black bear, even though Ursus americanus spends months every year curled up in a den, hibernating the winter away.

DECEMBER 18, 2003 -- Inactivity is a prime cause of osteoporosis in most animals, including humans. A notable exception is the black bear, even though Ursus americanus spends months every year curled up in a den, hibernating the winter away.

Related Articles


Seth Donahue, an assistant professor of biomedical engineering, has been studying bears to discover why their skeletons retain their strength in conditions that would reduce human bones to the consistency of soda crackers.

Using blood samples taken from five captive bears at Virginia Tech by Michael Vaughan, a professor of wildlife science, Donahue and his research colleagues monitored metabolic markers of bone metabolism throughout the bears' annual cycle. They discovered that, while bone breakdown increases during hibernation, bone production remains constant and may even peak as the bear emerges from hibernation.

Bears don't eat during their long winter's nap, so where does the calcium come from to rebuild their bones?

It turns out that bears are recycling. They don't urinate or defecate when they hibernate, so instead of excreting calcium from their bones, they are essentially putting it back where they found it.

"They don't have a way of getting rid of excess calcium, so the logical place to put it is back into bone," he says.

Age, another risk factor for osteoporosis, doesn't appear to affect bear bones either. Donahue and his colleagues have been testing bear bones' strength, porosity and mineral content, using bones donated by area hunters. They discovered that strength and mineral content increased significantly as the bears get older, while porosity remains constant.

Donahue's work illustrating how black bears' bone breakdown and production balance was published recently in the Journal of Experimental Biology, Vol. 206.

Donahue's team now plans to investigate the structural differences between human and bear versions of two hormones involved in regulating bone metabolism, calcitonin and parathyroid hormone.

The hope is that insights from the bears' hormonal strategy could lead to new therapies for human bone loss. "One component of age-related osteoporosis is inactivity," Donahue says. "Also, there's a decrease in bone formation in the older human population."

According to the Osteoporosis Foundation, the condition is responsible for more than 1.5 million fractures annually. One in two women and one in four men over the age of 50 will suffer an osteoporosis-related bone fracture.


Story Source:

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


Cite This Page:

Michigan Technological University. "Researcher Discovers Clues To Bear Bone Strength." ScienceDaily. ScienceDaily, 29 December 2003. <www.sciencedaily.com/releases/2003/12/031223072108.htm>.
Michigan Technological University. (2003, December 29). Researcher Discovers Clues To Bear Bone Strength. ScienceDaily. Retrieved March 31, 2015 from www.sciencedaily.com/releases/2003/12/031223072108.htm
Michigan Technological University. "Researcher Discovers Clues To Bear Bone Strength." ScienceDaily. www.sciencedaily.com/releases/2003/12/031223072108.htm (accessed March 31, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Tuesday, March 31, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Solitair Device Aims to Takes Guesswork out of Sun Safety

Solitair Device Aims to Takes Guesswork out of Sun Safety

Reuters - Innovations Video Online (Mar. 31, 2015) — The Solitair device aims to take the confusion out of how much sunlight we should expose our skin to. Small enough to be worn as a tie or hair clip, it monitors the user&apos;s sun exposure by taking into account their skin pigment, location and schedule. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Soda, Salt and Sugar: The Next Generation of Taxes

Soda, Salt and Sugar: The Next Generation of Taxes

Washington Post (Mar. 30, 2015) — Denisa Livingston, a health advocate for the Dinι Community Advocacy Alliance, and the Post&apos;s Abby Phillip discuss efforts around the country to make unhealthy food choices hurt your wallet as much as your waistline. Video provided by Washington Post
Powered by NewsLook.com
UnitedHealth Buys Catamaran

UnitedHealth Buys Catamaran

Reuters - Business Video Online (Mar. 30, 2015) — The $12.8 billion merger will combine the U.S.&apos; third and fourth largest pharmacy benefit managers. Analysts say smaller PBMs could also merge. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
S. Leone in New Anti-Ebola Lockdown

S. Leone in New Anti-Ebola Lockdown

AFP (Mar. 28, 2015) — Sierra Leone imposed a three-day nationwide lockdown Friday for the second time in six months in a bid to prevent a resurgence of the deadly Ebola virus. Duration: 01:17 Video provided by AFP
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