Sp. Weinstein et al., DEXAMETHASONE INHIBITS INSULIN-STIMULATED RECRUITMENT OF GLUT4 TO THECELL-SURFACE IN RAT SKELETAL-MUSCLE, Metabolism, clinical and experimental, 47(1), 1998, pp. 3-6
To test the hypothesis that glucocorticoids reduce insulin-stimulated
skeletal muscle glucose transport by inhibiting the recruitment of GLU
T4 glucose transporters to the cell surface, we determined the effect
of glucocorticoid treatment on cell-surface GLUT4 using the impermeant
glucose transporter photolabel, 2-N-4-(1-azi-2,2,2-trifluoroethyl)ben
zoyl-[2-(3) H]1,3-bis-(D-mannos-4-yloxy)-2-propylamine (ATB-[2-H-3]BMP
A), and GLUT4 immunoprecipitation, Male Sprague-Dawley rats were treat
ed with dexamethasone ([Dex] 0.9 mg/kg for 2 days) and compared agains
t pair-fed controls. 2-[H-3]deoxyglucose (2-[H-3]DG) uptake in isolate
d soleus muscles was measured under conditions in which uptake reflect
s glucose transport activity. In control muscles, 2-[H-3]DG uptake was
stimulated eightfold by insulin (20 nmol/L), Dex treatment reduced ma
ximal insulin-stimulated 2-[H-3]DG uptake by 48% +/- 4% (mean +/- SEM)
and decreased cell-surface (ATB-[2-H-3]BMPA-photolabeled) GLUT4 by 48
% +/- 3%, despite an increase in total muscle GLUT4 content of 26% +/-
7%, These findings indicate that glucocorticoid-induced inhibition of
insulin-stimulated glucose transport in muscle is due to impaired rec
ruitment of GLUT4 to the cell surface. Copyright (C) 1998 by W.B. Saun
ders Company.