Impaired insulin action in primary hyperaldosteronism

The presence of insulin resistance is frequently found in essential hyper-t ension. There are, however, only sparse data with respect to the potential presence of insulin resistance in patients with secondary hypertension. We have therefore undertaken a study to reveal the potential occurrence of ins ulin resistance in primary hyperaldosteronism (PH). The hyperinsulinemic eu glycemic clamp technique together with the evaluation of insulin receptor c haracteristics were used to study insulin resistance in 12 patients with PH . The measured parameters were compared to normal values in control subject s. We have found a significantly lower glucose disposal rate (M, mu mol/kg/ min) (18.7+/-6 vs. 29.3+/-4), decreased tissue insulin sensitivity index (M II, mu mol/kg/min per mU/l x100) (23.7+/-9.8 vs. 37.5+/-11.6) and also lowe r metabolic clearance rate of glucose (MCRg, ml/kg/min) (3.8+/-1.5 vs. 7.0/-1.1) in patients with primary hyperaldosteronism. The insulin receptor ch aracteristics on erythrocytes did not differ in primary hyperaldosteronism as compared to control healthy subjects. We thus conclude that insulin resi stance is also present in secondary forms of hypertension (primary hyperald osteronism) which indicates the heterogeneity of impaired insulin action in patients with arterial hypertension.