Insulin sensitivity in the pathogenesis of hypertension and hypertensive complications.

Epidemiologic and clinical studies suggest an association between hyperinsulinemia (and insulin resistance) and hypertension. This relationship is not present in secondary forms of hypertension and may persist despite adequate antihypertensive therapy. Normotensive offspring of hypertensive parents are also, as a group, insulin resistant and hyperinsulinemic. The association of hyperinsulinemia (and insulin resistance) with hypertension is more marked in the obese but present in lean hypertensive as well. Physiological mechanisms by which insulin might increase blood pressure include sympathetic nervous system stimulation and enhancement or renal sodium reabsorption. Evidence exists linking both of these mechanisms to hypertension. Insulin is also independently associated with myocardial infarction and microalbuminuria, two long term complications of high blood pressure. Experimentally induced decreases in insulin resistance and hyperinsulinemia, furthermore, have been associated with decreased blood pressure. In summary, the evidence suggests that hyperinsulinemia (and insulin resistance) exerts a pro-hypertensive effect that may be important in the pathogenesis of hypertension and hypertensive complications in some patients with essential hypertension.