Regulation of muscle glucose transport and glut-4 by nerve-derived
factors and activity-related processes.
Megeney, L. A., R. N. Michel, C. S. Boudreau, P. K. Fernando, M. H.
Tan, and A. Bonen.
Department of Kinesiology, University of Waterloo, Waterloo,
Ontario, N2L 3G1, Canada, Neuromuscular Research Laboratory, School
of Human Movement, Laurentian University, Sudbury, Ontario, P3E 2C6,
Canada, Department of Medicine, Dalhousie University, Halifax, Nova
Scotia, B3H 3J5, Canada
APStracts 2:0163R, 1995.
Glucose transport and GLUT4 were examined in muscles in which both
activity and nerve-derived factors were eliminated (denervation) and
in muscles in which only muscle activity was eliminated but in which
nerve-derived factors were maintained (tetrodotoxin (TTX) treatment).
After 3 days of denervation insulin-stimulated 3-O-methyl glucose
transport was markedly lowered in perfused rat hindlimb muscles (SOL,
PL, RG, WG; < 35%). GLUT-4 was also decreased by 11-65% in
denervated muscles. Blocking of muscle activity with TTX superfusion
of the sciatic nerve for 3 days, reduced the insulin-stimulated
glucose transport to the same extent as in the denervated muscles
(P>0.05). However, TTX treatment reduced GLUT-4 expression much
less in SOL PL and RG muscles than in the denervated muscles
(P<0.05). GLUT4 mRNA abundance was decreased in denervated
muscles but not in TTX-treated muscles. These results suggests that
muscle activity largely regulates the insulin signalling mechanisms
of glucose transport and that nerve-derived trophic factors affect
pre-translational events to regulate GLUT-4 expression.
Received 8 July 1994; accepted in final form 30 May 1995.
APS Manuscript Number R368-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 July 1995.