Insulin action in the polycystic ovary syndrome.

Research on insulin action in PCOS has been intensive after the identification of insulin resistance as a feature of the syndrome in 1980. It is now clear that PCOS is a metabolic as well as a reproductive disorder and an important cause of type 2 diabetes mellitus in women. The cellular and molecular mechanisms of insulin resistance in PCOS are distinct from those in other insulin resistance syndromes. Elucidating these mechanisms promises to provide considerable insight into insulin receptor signal specificity. Conversely, insulin resistance is now known to have an important role in the pathogenesis of the reproductive disturbances of PCOS. It is thought that one or several genetic defects may cause both the insulin resistance and reproductive abnormalities characteristic of PCOS.