Insulin and polycystic ovary syndrome: a new look at an old subject.

In recent years the metabolic implications of polycystic ovary syndrome (PCOS) have received a great deal of attention; in fact 50% of women with PCOS are obese and a similar percentage of subjects was found to show exaggerated insulin secretion and reduced insulin-stimulated glucose uptake. The presence of these features in women with PCOS has profound clinical implications in terms of morbidity due to diabetes mellitus, dyslipidemia, hypertension and cardiovascular disease. Moreover, hyperinsulinemia has recently been proposed as a possible independent risk factor for endometrial and breast cancer. In the light of these considerations, the importance of metabolic screening in patients with PCOS in order to improve their quality of life cannot be underestimated. In this review we analyze all the clinical pathologies in which hyperinsulinemia of PCOS could be involved. Furthermore, in order to clarify the possible mechanisms leading to the insulin disorders of the syndrome, we review the available data about the insulin receptor abnormalities, as well as those concerning the insulin resistance and the exaggerated insulin secretion. Finally, we examine the main therapeutic strategies to ameliorate the insulinemic status of PCOS patients in order to potentially be able to prevent the long-term consequences of this syndrome.