Polycystic ovary syndrome (PCOS) is the commonest endocrinopathy
affecting women of reproductive age, manifested with a variety of
clinical signs, none of which is pathognomonic. The association of
insulin resistance and reproductive abnormalities with clinical
hyper-androgenism in a woman was first demonstrated by Achard and Thiers
in the “diabetes of bearded woman.” The link of PCOS with insulin
resistance was subsequently established by clinical studies
characterizing the profound insulin resistance in obese and lean PCOS
patients. Insulin resistance, hyperinsulinemia, and beta-cell
dysfunction are very common in PCOS, but are not required for the
diagnosis. The numerous in vivo and in vitro data supporting the central
role of insulin resistance in the pathogenesis of PCOS found a broad
clinical application in the management of the syndrome, where the
regulation of cycle abnormalities and the facilitation of pregnancy in
obese PCOS patients was assisted by co-administration of agents such as
the well-known insulin sensitizers. The documentation of the presence of
insulin resistance contributed substantially to unravel several
metabolic components present in the syndrome. Today our knowledge about
PCOS appears to have broader health implications and to have profoundly
altered our view of the gravity of this condition
