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Time course of the response of carbohydrate metabolism to unloading of the soleusThe time course of the response of carbohydrate metabolism to unloading was studied in the soleus muscle of rats subjected to tail-cast suspension. In the fresh soleus, 12 hours of unloading led to higher concentrations of glycogen and lower activity ratios of both glycogen synthase and glycogen phosphorylase. These changes were still evident on day three. Thereafter, the increased glycogen concentration apparently diminished the activity ratio of glycogen synthase, leading to a subsequent fall in the total glycogen content after day one. After 24 hours of unloading, when no significant atrophy was detectable, there was no differential response to insulin for in vitro glucose metabolism. On day three, the soleus atrophied significantly and displayed a greater sensitivity to insulin for most of these parameters compared to the weight-bearing control muscle. However, insulin sensitivity for glycogen synthesis was unchanged. These results showed that the increased sensitivity to insulin of the unloaded soleus is associated with the degree of muscle atrophy, likely due to an increased insulin binding capacity relative to muscle mass. This study also showed that insulin regulation of glucose uptake and of glycogen synthesis is affected differentially in the unloaded soleus muscle.
Document ID
19890025252
Document Type
Reprint (Version printed in journal)
Authors
Henriksen, Erik J. (Arizona Univ. Tucson, AZ, United States)
Tischler, Marc E. (Arizona, University Tucson, United States)
Date Acquired
August 13, 2013
Publication Date
March 1, 1988
Publication Information
Publication: Metabolism
Volume: 37
ISSN: 0026-0495
Subject Category
LIFE SCIENCES (GENERAL)
Funding Number(s)
CONTRACT_GRANT: NAGW-227
CONTRACT_GRANT: NAG2-384
Distribution Limits
Public
Copyright
Other