Local effect of vanadate on interstitial glucose and lactate concentrations in human skeletal muscle

The aim of this study was to investigate the local effect of the insulin-mimetic agent vanadate on glucose metabolism in human skeletal muscle in vivo. Interstitial concentrations of glucose and lactate were determined by microdialysis at a low flow rate in the quadriceps femoris muscle of 18 men. In the same leg two microdialysis catheters were inserted. In one catheter, the perfusion medium was supplemented with sodium metavanadate (10-100 mM) after a basal period, the other catheter served as control. In the catheter perfused with metavanadate, the interstitial glucose concentration was decreased by 13-50% compared to the control catheter (p<0.05). The lactate concentration was higher in the 50 mM and 100 mM metavanadate catheters compared to control (39-89%, p<0.05). There was no difference between control and metavanadate catheters in urea concentrations. Five of the subjects were insulin-resistant and for them the results were similar, although the effect was somewhat smaller. The decreased interstitial glucose concentration, and the increased lactate concentration, in the vicinity of the microdialysis catheter most likely reflects an increased cellular glucose uptake. The present study thus indicates that vanadate mimics the effect of insulin in human skeletal muscle in vivo.