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Effect of Denervation and Reinnervation on Oxidation of [6‐ 14 C]Gucose by Rat Skeletal Muscle Homogenates
Author(s) -
DuBois Debra C.,
Max Stephen R.
Publication year - 1983
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1983.tb08039.x
Subject(s) - denervation , reinnervation , medicine , endocrinology , oxidative phosphorylation , extensor digitorum longus muscle , skeletal muscle , chemistry , oxidative metabolism , metabolism , biology , anatomy , biochemistry
We studied the effects of denervation and reinnervation of the rat extensor digitorum longus muscle (EDL) on the oxidation of [6‐ 14 C]glucose to 14 CO 2 . The rate of 14 CO 2 production decreased dramatically following denervation, and the decrease became significant 20 days after nerve section. Prior to day 20, changes apparently reflected the decline of muscle mass. Decreased 14 CO 2 production was due to reduced capacity of the enzymatic system (apparent V max ); there was no change in apparent affinity for glucose (apparent K m ). Mixing experiments revealed that the loss of oxidative capacity following denervation is not caused by production of soluble inhibitors by degenerating muscle. Oxidative metabolism, as measured by 14 CO 2 evolution, recovered during reinnervation. Surprisingly, the specific activity in reinnervated muscles displayed an “overshoot” of approximately 50%, which returned to control by day 60, possibly reflecting increased energy demand by the growing muscle. The time‐course of the denervation‐mediated change indicates that altered oxidative capacity is secondary to events that initiate denervation changes in muscle. Nevertheless, diminished oxidative capacity may be of considerable metabolic significance in denervated muscle.