Effect of Extracellular Palmitate on 2-Deoxy-d-glucose Uptake in Muscle fromAd LibitumFed and Calorie Restricted Rats

Abstract

We studied the effect of a high physiologic concentration of palmitate (1mM) onin vitro2-deoxy-D-glucose (2DG) uptake by flexor digitorum brevis (FDB) muscle fromad libitumfed rats (AL) and rats fed 60% ofad libitumintake (CR) for 20 days. CR did not alter muscle 2DG uptake in the absence of insulin, but relative to AL, CR significantly (p<0.01) increased 2DG uptake in the presence of 20,000μU/ml insulin. This effect of CR persisted in the presence of 1mM palmitate. The presence of 1mM palmitate significantly (p<0.01) impaired 2DG glucose uptake, both in the presence and absence of insulin, to the same extent in AL and CR muscle, despite an 18% decrease in FABPpm expression with CR. Thus, although CR profoundly affects insulin-mediated muscle glucose uptake, it does not alter the ability of extracellular fatty acid to modulate glucose utilization by skeletal muscle.