AJP - Regulatory, Integrative and Comparative Physiology, Vol 270, Issue 6 1355-R1360, Copyright © 1996 by American Physiological Society

ARTICLES

Effect of cross-reinnervation on the expression of GLUT-4 and GLUT-1 in slow and fast rat muscles

E. Johannsson, O. Waerhaug and A. Bonen
Norwegian University of Sport and Physical Education, Oslo, Norway.

We determined whether the twitch-velocity phenotype or the metabolic phenotype of a muscle influences the content of GLUT-4 and GLUT-1 proteins. The soleus (Sol) and extensor digitorum longus (EDL) muscles were cross-reinnervated (X-Sol, X-EDL). After 3 mo the X-EDL had become enriched in slow-twitch oxidative (SO) fibers (70.5% SO) compared with its control (3.8% SO), whereas the X-Sol became enriched in fast-twitch oxidative-glycolytic (FOG) fibers (78.6% FOG) compared with its control (10% FOG). Thus the twitch phenotype of X-Sol shifted to fast-twitch muscle, whereas X-EDL shifted to a slow-twitch muscle. In the X-EDL, the oxidative nature of the X-EDL was increased to 97% oxidative fibers compared with 43% oxidative fibers in the normal EDL. In the Sol the oxidative nature of the X-Sol was retained at 100%. GLUT-4 content was increased 1.6-fold in the X-EDL (P < 0.05) but was not changed in the X-Sol (P > 0.05). GLUT-1 content was increased fourfold in X-EDL but was not altered in the X-Sol. We conclude that GLUT-4 and GLUT-1 content in muscle is related to the oxidative phenotype of the muscle rather than the twitch-velocity phenotype.

This article has been cited by other articles:

				D. Roy, E. Johannsson, A. Bonen, and A. Marette Electrical stimulation induces fiber type-specific translocation of GLUT-4 to T tubules in skeletal muscle Am J Physiol Endocrinol Metab, October 1, 1997; 273(4): E688 - E694. [Abstract] [Full Text] [PDF]