Part of the book: Insulin Resistance
Polycystic ovary syndrome (PCOS) is an endocrine-metabolic disorder characterized by multiple hormonal imbalances, reflecting on the clinical presentation. Among them, the insulin resistance (IR), defined as a metabolic state characterized by a decrease in cellular ability to respond to insulin signaling, is a key feature of PCOS independently of obesity. Thus, IR occurs in more than 70% of obese PCOS women and in 30–50% of lean ones. Compensatory high insulin levels are both a symptom and an underlying physiopathological driver of PCOS. Insulin appears to disrupt all components of the hypothalamic-pituitary-ovarian axis, and ovarian tissue IR results in impaired metabolic signaling but intact mitogenic and steroidogenic activity, favoring hyperandrogenemia. The latter is the main culprit of the clinical picture in PCOS. Testing for IR can be helpful to rule out other conditions that are commonly misdiagnosed as PCOS and to recommend an appropriate treatment for the different PCOS phenotypes.
Part of the book: Polycystic Ovarian Syndrome