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Reduced glycogen phosphorylase activity in denervated hindlimb muscles of rat is related to muscle atrophy and fibre type


Wallis, MG and Appleby, GJ and Youd, JM and Clark, MG and Penschow, JD, Reduced glycogen phosphorylase activity in denervated hindlimb muscles of rat is related to muscle atrophy and fibre type, Life Sciences, 64, (4) pp. 221-228. ISSN 0024-3205 (1999) [Refereed Article]

DOI: doi:10.1016/S0024-3205(98)00557-8


Changes in the activity of muscle glycogen synthase or phosphorylase (GP) may be responsible for the deregulation of glycogen synthesis and storage which occurs in diabetes mellitus. To clarify the relationship between muscle atrophy, fibre type, insulin-stimulated glucose uptake and GP activity during insulin resistance, we used sciatic nerve severance to induce insulin resistance in rat hindlimb muscles and compared the above parameters in muscles with a range of fibre types. Changes were analysed by comparison with the contralateral hindlimb, which bears more weight due to denervation of the opposing limb, as well as the sham-operated and contralateral limb of a separate rat. Denervation caused a decrease in insulin-stimulated glucose uptake by 1 day after denervation and a decline of GP activity after 7 days in all muscles investigated. GP activity decreased by 73% in soleus, 36% in red gastrocnemius, 35% in tibialis and 13% in white gastrocnemius, which was related to the degree of muscle atrophy and inversely related to the overall GP activity in non-denervated muscles. GP activity in muscles of the contralateral limb from the denervated rat did not differ from either hindlimb of the sham-operated rat. We conclude that the fibre-type related reduction in insulin-stimulated glucose uptake of denervated muscle determines the change in its metabolism and it is this metabolic change which determines the mechanism, rate and degree of muscle atrophy, which is directly related to the decline in GP activity.

Item Details

Item Type:Refereed Article
Research Division:Biomedical and Clinical Sciences
Research Group:Medical biochemistry and metabolomics
Research Field:Medical biochemistry - carbohydrates
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:Wallis, MG (Ms Michelle Gaye Wallis)
UTAS Author:Appleby, GJ (Mr Geoffrey Appleby)
UTAS Author:Youd, JM (Miss Joanne Maree Youd)
UTAS Author:Clark, MG (Professor Michael Clark)
UTAS Author:Penschow, JD (Dr Jennifer Penschow)
ID Code:17084
Year Published:1999
Web of Science® Times Cited:16
Deposited By:Biochemistry
Deposited On:1999-08-01
Last Modified:2000-05-25

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