Insulin resistance in essential hypertension is characterized by impaired insulin stimulation of blood flow in skeletal muscle.

OBJECTIVE

To determine whether insulin-stimulated blood flow in patients with mild essential hypertension is altered.

SUBJECTS

Eleven untreated mildly hypertensive patients [aged 35 +/- 2 years, body mass index 25.1 +/- 0.4 kg/m2, mean arterial pressure 110 +/- 2 mmHg (means +/- SEM) and 10 matched normotensive subjects (mean arterial pressure 94 +/- 3 mmHg).

METHODS

Blood flow was quantitated directly in skeletal muscle both basally and during supraphysiologic hyperinsulinemia (serum insulin approximately = 450 mU/l) using radiowater ([15O]H2O) and positron emission tomography. Whole-body and femoral muscle glucose uptakes were determined using the euglycemic insulin clamp technique, [18F]-2-fluoro-2-deoxy-D-glucose and positron emission tomography.

RESULTS

Rates of whole-body and femoral muscle glucose uptake were significantly lower in the hypertensive than in the normotensive group. Insulin increased muscle blood flow by 91% in the normotensive group, but only by 33% in the hypertensive group.

CONCLUSIONS

The ability of insulin to stimulate blood flow in patients with mild essential hypertension is impaired.