Pressure pain threshold and β-endorphins plasma level are higher in lean polycystic ovary syndrome women.

BACKGROUND: Despite some evidence that indicates that the evolution of polycystic ovary syndrome (PCOS) is related to the activity of the endogenous opioid system, and that concentration of plasma β-endorphin levels can increase pain threshold, there are no studies which evaluate pressure pain threshold in the PCOS women population.

METHODS: In 48 lean women with PCOS and 38 lean women without this disorder plasma β-endorphins and PPT were measured.

RESULTS: The β-endorphins level was higher in the PCOS group compared to the controls (15.28±2.49 pg/mL vs. 6.33±1.71 pg/mL, P<0.001). In PCOS group PPTs measured on deltoid and trapezius muscles were higher compared to the controls (9.33±1.3 kg/cm² vs. 5.19±0.57 kg/cm², P<0.001; 8.23±1.04 kg/cm² vs. 4.79±0.55 kg/cm², P<0.001). The β-endorphin levels positively correlated with PPTs in PCOS group. Increase in β-endorphin level of 1 pg/mL was associated with increase of PPT value on deltoid muscle of 0.23 kg/cm² (R=0.632, P=0.011) and of 0.18 kg/cm² on trapezius muscle (R=0.588, P=0.037). There were no correlations between testosterone level and PPT in PCOS group.

CONCLUSIONS: β-endorphin serum level as well as PPT are higher in lean PCOS group than in controls. We found correlations between β-endorphin levels and PPT in the PCOS group. It may suggest the role of endogenous opioids in the pathogenesis of PCOS and also that the increases in circulating plasma β-endorphins concentration can increases PPT in this group.