['In individuals with atherosclerotic risk factors, endothelial dysfunction (ED) appears as an early phase in the development of clinical symptoms. Recent studies indicate that adropin, a newly identified peptide, participates in cardiovascular health through the regulation of several metabolic events including angiogenesis and blood flow. In this study, we aimed to determine the relation of adropin with biochemical and radiologic parameters which reflect ED such as endothelial nitric oxide synthase (eNOS), endothelin 1 (ET-1), nitric oxide (NO) and flow-mediated dilatation (FMD) along with the routine biochemical measurements in patients recently diagnosed with metabolic syndrome (MetS).', "Fasting blood samples from 110 patients with MetS diagnosed according to the NCEP ATP III-2005 criteria were collected to measure the concentrations of adropin and other parameters including the lipid profile, insulin and glucose. Serum NOx concentrations were determined by measuring NO2 plus NO3. FMD test was performed by ultrasonography, and patients were stratified as FMD (+) or (-). Data were compared between these two subgroups and also with matching healthy controls (n=50). Biochemical data were evaluated using Student's t or Mann-Whitney U tests.", 'Fifty-nine subjects had ED (+) and the remaining 101 subjects were ED (-). In the first group, adropin levels were significantly lower than the latter (2.13±1.05 vs. 3.41±1.63 ng/mL, respectively; p<0.001) and independently associated with FMD positivity as assessed by the logistic regression analysis.'] Are low concentrations of adropin associated with endothelial dysfunction as assessed by flow-mediated dilatation in patients with metabolic syndrome?