Nitric oxide and fibrinogen in polycystic ovary syndrome: associations with insulin resistance and obesity.
OBJECTIVE: Nitric oxide (NO) and fibrinogen levels, two markers of vascular disease, are associated with insulin resistance, a common trait in women with polycystic ovary syndrome (PCOS). STUDY DESIGN: Case-control study including 31 women with PCOS and 21 age-matched women with regular, ovulatory cycles, normal androgen levels and idiopathic hirsutism (control group). Nitrite/nitrate concentration (index of endothelium-derived NO) and fibrinogen plasma levels were assessed and analysed in association with anthropometric, metabolic and hormonal variables. RESULTS: The groups were similar in terms of age, positive family history of diabetes and Ferriman-Gallwey hirsutism score. Nitrite/nitrate and fibrinogen levels were also similar in the two groups. In contrast, in PCOS patients, insulin levels and the homeostatic model assessment were negatively correlated with NO production (r=-0.39, p=0.03 and r=-0.41, p=0.02, respectively). Age, BMI, waist circumference and waist-to-hip ratio were positively correlated with fibrinogen in both groups. CONCLUSION: The present data indicate a negative, BMI-independent association between NO levels and insulin resistance in PCOS patients. Further studies are required to clarify the role of androgens on the pathogenesis of endothelial dysfunction in PCOS and investigate androgen action and/or the gene receptor modulating NO secretion.