[The insulin sensitivity concept].

Abstract

Insulin resistance was already suspected in the thirties from clinical observations in diabetic patients, then better appreciated in the early sixties with the development of insulin radioimmunoassay, and finally confirmed in the last 20 years by using various sophisticated methods able to quantify insulin action. First demonstrated in obese and/or type 2 diabetic patients, the diminution of insulin sensitivity may in fact concern a much larger population. The concept of insulin sensitivity gained a considerable importance when Reaven, in 1988, emphasized the role of insulin resistance in different human diseases. The metabolic syndrome or syndrome X is characterized by the association of various cardiovascular risk factors (among which impaired glucose tolerance, arterial hypertension and dyslipidaemias), all closely linked to insulin resistance which is indeed the core of the syndrome. Even if insulin action signalling appears to be rather complex and the mechanisms leading to insulin resistance still largely unknown, it is essential to develop pharmacological or non pharmacological strategies to improve insulin sensitivity for treating insulin-resistant individuals. Such an approach should allow not only to provide a better blood glucose control in patients with type 2 diabetes, but also to improve the cardiovascular prognosis of numerous patients, with or without diabetes mellitus, who have the metabolic syndrome.