Effect of extracellular palmitate on 2-deoxy-D-glucose uptake in muscle from ad libitum fed and calorie restricted rats

We studied the effect of a high physiologic concentration of palmitate (1mM ) on in vitro 2-deoxy-D-glucose (2DG) uptake by flexor digitorum brevis (FD B) muscle from ad libitum fed rats (AL) and rats fed 60% of ad libitum inta ke (CR) for 20 days. CR did not alter muscle 2DG uptake in the absence of i nsulin, but relative to AL, CR significantly (p<0.01) increased 2DG uptake in the presence of 20,000 mu U/ml insulin. This effect of CR persisted in t he presence of 1mM palmitate. The presence of 1mM palmitate significantly ( p<0.01) impaired 2DG; glucose uptake, both in the presence and absence of i nsulin, to the same extent in AL and CR muscle, despite an 18% decrease in FABPpm expression with CR. Thus, although CR profoundly affects insulin-med iated muscle glucose uptake, it does not alter the ability of extracellular fatty acid to modulate glucose utilization by skeletal muscle. (C) 1998 Ac ademic Press.