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Bone formation is not impaired by hibernation (disuse) in black bears Ursus americanus

Journal of Experimental Biology

By:
, , ,
DOI: 10.1242/jeb.00671

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Abstract

Disuse by bed rest, limb immobilization or space flight causes rapid bone loss by arresting bone formation and accelerating bone resorption. This net bone loss increases the risk of fracture upon remobilization. Bone loss also occurs in hibernating ground squirrels, golden hamsters, and little brown bats by arresting bone formation and accelerating bone resorption. There is some histological evidence to suggest that black bears Ursus americanus do not lose bone mass during hibernation (i.e. disuse). There is also evidence suggesting that muscle mass and strength are preserved in black bears during hibernation. The question of whether bears can prevent bone loss during hibernation has not been conclusively answered. The goal of the current study was to further assess bone metabolism in hibernating black bears. Using the same serum markers of bone remodeling used to evaluate human patients with osteoporosis, we assayed serum from five black bears, collected every 10 days over a 196-day period, for bone resorption and formation markers. Here we show that bone resorption remains elevated over the entire hibernation period compared to the pre-hibernation period, but osteoblastic bone formation is not impaired by hibernation and is rapidly accelerated during remobilization following hibernation.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Bone formation is not impaired by hibernation (disuse) in black bears Ursus americanus
Series title:
Journal of Experimental Biology
DOI:
10.1242/jeb.00671
Volume
206
Issue:
23
Year Published:
2003
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Experimental Biology
First page:
4233
Last page:
4239
Number of Pages:
7