Polycystic Ovary Syndrome as Metabolic Disease: New Insights on Insulin Resistance

Abstract

Polycystic ovary syndrome (PCOS) is a very frequent disease that affects reproductive ability and menstrual regularity. Other than the criteria established at the Rotterdam consensus, in these last few years a new issue, insulin resistance, has been found frequently, and at a very high grade, in patients with PCOS. Insulin resistance occurs for several factors, such as overweight and obesity, but it is now clear that it occurs in patients with PCOS with normal weight, thus supporting the hypothesis that insulin resistance is independent of body weight. Evidence shows that a complex pathophysiological situation occurs that impairs post-receptor insulin signalling, especially in patients with PCOS and familial diabetes. In addition, patients with PCOS have a high incidence of non-alcoholic fatty liver disease related to the hyperinsulinaemia. This narrative review focuses on the recent new insights about insulin resistance in patients with PCOS, to better understand the metabolic impairment accounting for most of the clinical signs/symptoms of PCOS.

Keywords: Familial diabetes; hyperinsulinemia; inositols; insulin resistance; lipoic acid; non-alcoholic fatty liver disease; polycystic ovary syndrome.

Figure 1:. Schematic summary of insulin actions on the reproductive axis

Figure 2:. Glucose (panel A) and insulin (panel B) response to the oral glucose tolerance test in a group of patients who are obese with polycystic ovary syndrome (n=25) and healthy controls who are obese (n=23)

Figure 3:. Insulin secretion and removal from the general circulation depend on pancreatic activity and from the clearance exerted by various organs: liver (-50%), kidney (-30%), muscles (-15 to -35%)