Skeletal muscle is a primary site of insulin resistance in essential hypertension

To determine the contribution of skeletal muscle to the insulin resistance of essential hypertension, insulin-stimulated forearm glucose uptake was quantitated in 12 control (age, 32 +/- 3 years) and 12 hypertensive subjects (age, 36 +/- 2 years) using the forearm perfusion technique. Peripheral insulin levels were raised acutely (approximately 60 microU/mL), while blood glucose concentration was clamped at its basal value (90 mg/dL) by a variable glucose infusion. During insulin stimulation, whole body glucose uptake was lower in hypertensive (4.5 +/- .3 mg.kg-1.min-1) than in normal subjects (5.8 +/- .4 mg.kg-1.min-1, P less than .05). Similarly, the amount of glucose taken up by the forearm was markedly reduced in the hypertensive (5.3 +/- .91 mg.L-1.min-1) compared with the control group (8.7 +/- 1.1 mg.L-1.min-1). No appreciable difference was observed as to forearm blood flow (39 +/- 4 mL.L-1.min-1 and 37 +/- 5 mL.L-1.min-1) in hypertensive patients. These results indicate that skeletal muscle is a major site of insulin resistance in essential hypertension and that this defect is independent of muscle perfusion.