OBJECTIVE: To assess the effects of weight loss on serum adipokine levels in polycystic ovary syndrome (PCOS).METHODS: We determined serum leptin, adiponectin, resistin, and visfatin levels in 60 overweight/obese women with PCOS and 48 BMI-matched female volunteers. Measurements were repeated after 24 weeks of treatment with orlistat 120 mg 3 times per day along with an energy-restricted diet.RESULTS: At baseline, serum visfatin concentration was higher in patients with PCOS than in controls (p = 0.036); serum levels of leptin, adiponectin, and resistin did not differ between the two groups. After 24 weeks, a significant reduction in BMI and waist circumference was observed in both patients with PCOS and controls (p < 0.001 vs. baseline in both groups). Also serum leptin levels decreased in both patients with PCOS and controls (p < 0.001 vs. baseline in both groups). The reduction in serum leptin levels did not differ between groups. Serum adiponectin, resistin, and visfatin levels did not change in either group.CONCLUSIONS: Leptin, adiponectin, and resistin do not appear to play major pathogenetic roles in overweight/obese patients with PCOS. In contrast, visfatin emerges as a potentially important mediator of the endocrine abnormalities of these patients. However, serum visfatin levels are not substantially affected by weight loss.