Role of insulin resistance on fertility - Focus on polycystic ovary syndrome.

Several lines of evidence show that gonadal functions and insulin sensitivity display multifaceted relationships, which extend far beyond the well-known association between polycystic ovary syndrome (PCOS), obesity, and metabolic syndrome. In this brief review, we will summarize the main findings showing the pathophysiological role of insulin resistance in impairing reproductive functions. Extreme phenotypes of severe insulin resistance, due to primary defects in insulin receptor or to lipodystrophy syndromes, provide unique opportunities for the modeling of interactions between insulin signaling and ovarian endocrine functions. In addition, recent studies further suggest that common forms of dysfunctional adiposity, as well as altered production of adipokines, could underlie important pathophysiological links between metabolic syndrome and infertility.