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Responses of skeletal muscle to unloading - A reviewSuspension models were used to study muscle response to reduced activity. During 6 days of tail casting, the soleus (SOL) atrophies while the extensor digitorum longus grows relatively normally. After discounting those changes in both muscles due primarily to increased secretion of adrenal hormones, the following conclusions regarding the specific responses of the SOL could be drawn: (1) Atrophy is probably due primarily to increased protein degradation; (2) Decreased synthesis of glutamine may result from reduced availability of ammonia due to diminished use of ATP; (3) Greater muscle glycogen seems to reflect an increased response to insulin of glucose uptake which leads to greater glucose metabolism; and (4) Faster catabolism of branched-chain amino acids can be attributed to enhanced flux through ketoacid dehydrogenase. Studies by others using tail casted suspended rats showed in the SOL: (1) a gradual switch from type 1 to type 2 fibers; (2) increased acid protease activity; and (3) altered muscle function and contractile duration. Using harness suspended rats, others showed in the SOL: (1) significant atrophy; (2) increased numbers of glucocorticoid receptors; and (3) no change in muscle fatigability.
Document ID
19860045641
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Tischler, M. E.
(Arizona Univ. Tucson, AZ, United States)
Jaspers, S. R.
(Arizona Univ. Tucson, AZ, United States)
Henriksen, E. J.
(Arizona Univ. Tucson, AZ, United States)
Jacob, S.
(Arizona, University Tucson, United States)
Date Acquired
August 12, 2013
Publication Date
December 1, 1985
Publication Information
Publication: Physiologist, Supplement
Volume: 28
ISSN: 0031-9376
Subject Category
Life Sciences (General)
Accession Number
86A30379
Funding Number(s)
CONTRACT_GRANT: NAGW-227
CONTRACT_GRANT: NIH-AM-28647
Distribution Limits
Public
Copyright
Other

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