Dipeptidyl peptidase 4 (DPP-4) is thought to play a role in the pathophysiology of metabolic and inflammatory diseases. Increased ADA activity has been suggested to induce insulin resistance and inflammation. We investigated DPP-4 and ADA activities, serum nitric oxide (NO) level and nitric oxide synthase (NOS) activity which are the oxidative stress parameters in patients with PCOS. Fifty two women with PCOS and 41 healthy women were included in this study. Serum ADA activity (0.33 (0.170.67) vs 0.26 (0.120.60) IU/l; P=0.006), NO level (24.5 (13.2558) vs 12.25 (624.50) μmol/l; P<0.001) and NOS activity (5.46 (3.3812.71) vs 4.54 (2.5510.13) IU/ml; P<0.001) were significantly higher in PCOS group while there was no difference in serum DPP-4 activity (19.54±7.01 and 18.24±6.73 IU/l; P=0.369) between the groups. The groups were divided into subgroups as obese and nonobese. In obese PCOS group; ADA, NO and NOS were significantly higher than obese controls (P=0.044, P<0.001 and P<0.001), while there was no difference in DPP-4 activity (P=0.356) between the groups. In nonobese PCOS group; NO and NOS were significantly higher than nonobese controls (P<0.001 and P=0.006), while there were no differences in DPP-4 and ADA activity (P=0.802 and P=0.128). There was a negative correlation between ADA and DPP-4 activity in PCOS group (P=0.047). A positive correlation was observed between ADA and BMI in the whole group (P=0.022). In conclusion, we found that there was no significant change in serum DPP-4 activity in women with PCOS. However, we demonstrated increased serum ADA activity as well as its association with obesity in PCOS. Also, our finding that increased NO level and NOS activity in PCOS which is independent of obesity may result from a compensatory mechanism for the oxidative stress in PCOS.
20 - 23 May 2017
European Society of Endocrinology