Effect of immobilization on glucose transport and glucose transporter
expression in rat skeletal muscle.
Ploug, Thorkil, Tetsuo Ohkuwa, Aase Handberg, John Vissing, and Henrik Galbo.
Department of Medical Physiology, The Panum Institute, University of
Copenhagen, Denmark. Nagoya Institute of Technology, Nagoya 464, Japan.
APStracts 2:0011E, 1995.
The effect of 42-48 hours of immobilization by casting on Vmax for 3-O
-methylglucose (3-O-MG) transport in skeletal muscle was studied in the
perfused rat hindquarter. Immobilization resulted in a decrease of 42% for
maximum insulin stimulated 3-O-MG transport in fast twitch red fibers and a
decrease of 42% for contraction stimulated transport in slow twitch red
fibers compared to non-immobilized control muscle. No effect of
immobilization on 3-O-MG transport was found in fast twitch white muscle.
During combined action of insulin and muscle contractions glucose transport
was always identical in immobilized and control muscle. Western blot did not
detect any decrease in GLUT1 protein nor in GLUT4 protein with
immobilization. Furthermore, in fast twitch red fibers insulin receptor
number and receptor kinase activity did not differ between immobilized and
control muscle. It is concluded that during short term immobilization a
resistance of muscle glucose transport to stimulation develops which is fiber
type specific and selective for either insulin or contractions. The
resistance can be overcome by the combined action of insulin and contractions
and reflect other factors than glucose transporter number and insulin
receptor binding and receptor kinase activity.
Received 9 May 1994; accepted in final form 2 January 1995.
APS Manuscript Number E175-4.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 February 1995.