In vivo effects of dexamethasone and sucrose on glucose transport (
glut4) protein tissue distribution.
Coderre, Lise, Gino A. Vallega, Paul F. Pilch, Stuart R. Chipkin.
Department of Biochemistry, Division of Endocrinology, Diabetes and
Metabolism, Boston University School of Medicine, Boston, MA
02118
APStracts 3:0068E, 1996.
Tissue-specific changes in GLUT4 were compared in three different rat
models inducing varying degrees of hyperinsulinemia with or without
hyperglycemia and hypertriglyceridemia: 1. sucrose feeding (SUC), 2.
subcutaneous dexamethasone administration (DEX) and 3. a combination
of both treatments (DEX/SUC). SUC raised circulatory insulin and
triglyceride levels without affecting plasma glucose while both DEX
and DEX/SUC induced significant hyperinsulinemia, hyperglycemia and
hypertriglyceridemia. In adipocytes and skeletal muscle, SUC feeding
was not associated with any change in total cellular GLUT4 levels.
However, SUC induced a 7-fold increase in fat cell plasma membrane
GLUT4 levels in the basal state and inhibited GLUT4 translocation in
response to insulin. Administration of DEX or DEX/SUC diminished
GLUT4 expression in fat cells, increased it in skeletal muscle, but
did not induce any change in heart. Similar to SUC feeding, DEX and
DEX/SUC also increased the amount of GLUT4 detected at the plasma
membrane of adipocytes in the basal state and inhibited GLUT4
translocation in response to insulin. These results emphasize the
specific regulation of GLUT4 in insulin-sensitive tissues.
Received 30 August 1995; accepted in final form 13 March 1996.
APS Manuscript Number E422-5.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 1 April 96