['Insulin resistance might play a role in the pathogenesis of polycystic ovarian syndrome (PCOS). The family of glycoprotein 130 (gp130) cytokines could influence insulin action. One of these cytokines is interleukin (IL)-6, which exerts a short-term insulin-sensitizing effect, whereas in a long-term period, it might induce insulin resistance. Some other gp130 activators are supposed to have beneficial metabolic effects. Gp130 is present in the circulation in the soluble form (sgp130), which inhibits intracellular gp130 signaling. The aim of the present study was to estimate the relation between sgp130 and insulin sensitivity in women with PCOS.', 'We studied 78 women with PCOS (35 lean and 43 obese) and 34 healthy women (18 lean and 16 obese). The euglycemic-hyperinsulinemic clamp and the measurements of serum sgp130, IL-6, soluble IL-6 receptor (sIL-6R), and sex hormones were performed.', 'Both obesity and PCOS were characterized by an increased sgp130 (P < 0.0001 and P = 0.0002, respectively). sIL-6R concentration was lower (P = 0.0036) in women with PCOS independently of obesity. Serum sgp130 was negatively correlated with insulin sensitivity when control and PCOS women were analyzed together (r = -0.36, P < 0.0001) and in the PCOS subjects separately (r = -0.34, P = 0.002). In multiple regression analysis, this correlation was significant after adjustment for BMI, waist, percent of body fat, postload glucose and insulin, triglycerides, and high-sensitive C-reactive protein.'] Is serum soluble glycoprotein 130 concentration inversely related to insulin sensitivity in women with polycystic ovary syndrome?