[Arterial hypertension, hyperinsulinism and insulin resistance]

The incidence of hypertension is increased in obesity, a state associated with an insulin resistance syndrome. By using an euglycemic clamp method, Ferrannini et al. demonstrated the existence of an insulin resistance state in patients with essential hypertension. However, the body mass index of the subjects studied appeared to be slightly excessive. This abnormality has not been observed in patients with secondary hypertension. Insulin resistance is probably localized to peripheral tissues such as muscles and may be associated with other cellular abnormalities. Can insulin resistance, characterized by a raised circulating insulin concentration in the presence of normal blood glucose, be responsible for certain "modifications" associated with essential hypertension? Insulin induces sodium retention and increases the aldosterone-secreting effect of angiotensin II. These effects are likely to promote a rise in blood pressure and an increase in the sensitivity of vessels to endogenous substances. Moreover, insulin is a known growth factor and is involved in lipoprotein metabolism. If insulin resistance plays an important role in the maintenance of complications of essential hypertension, it is important that the treatments used tend to correct this anomaly. Thiazide diuretics and beta-blockers aggravate insulin resistance while angiotensin converting-enzyme inhibitors correct this condition.