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Bone and hormonal changes induced by skeletal unloading in the mature male ratTo determine whether the rat hindlimb elevation model can be used to study the effects of spaceflight and loss of gravitational loading on bone in the adult animal, and to examine the effects of age on bone responsiveness to mechanical loading, we studied 6-mo-old rats subjected to hindlimb elevation for up to 5 wk. Loss of weight bearing in the adult induced a mild hypercalcemia, diminished serum 1,25-dihydroxyvitamin D, decreased vertebral bone mass, and blunted the otherwise normal increase in femoral mass associated with bone maturation. Unloading decreased osteoblast numbers and reduced periosteal and cancellous bone formation but had no effect on bone resorption. Mineralizing surface, mineral apposition rate, and bone formation rate decreased during unloading. Our results demonstrate the utility of the adult rat hindlimb elevation model as a means of simulating the loss of gravitational loading on the skeleton, and they show that the effects of nonweight bearing are prolonged and have a greater relative effect on bone formation in the adult than in the young growing animal.
Document ID
20040142114
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Dehority, W.
(University of California and Division of Endocrinology, Veterans Affairs Medical Center San Francisco 94121, California 940351, United States)
Halloran, B. P.
Bikle, D. D.
Curren, T.
Kostenuik, P. J.
Wronski, T. J.
Shen, Y.
Rabkin, B.
Bouraoui, A.
Morey-Holton, E.
Date Acquired
August 22, 2013
Publication Date
January 1, 1999
Publication Information
Publication: The American journal of physiology
Volume: 276
Issue: 1 Pt 1
ISSN: 0002-9513
Subject Category
Aerospace Medicine
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Musculoskeletal
NASA Center ARC
Non-NASA Center

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