LAUSR

RESEARCH QUESTION Is endometrial expression of anti-Müllerian hormone (AMH) and its receptor II (AMH-R) altered in women with polycystic ovary syndrome (PCOS) and affected by lifestyle intervention? DESIGN Endometrial immunostaining of AMH and AMH-R was evaluated in obese women with PCOS (OB-PCOS, n = 18) before and after 3 months of lifestyle intervention, as well as in BMI-matched controls (OB-C, n = 10), normal-weight women with PCOS (n = 11) and healthy normal-weight controls (n = 11). RESULTS Before lifestyle modification, serum concentrations of AMH were higher in women with PCOS compared with BMI-matched controls, but there were no differences in endometrial immunostaining of AMH or AMH-R between the groups. Following lifestyle modification, a subgroup of OB-PCOS women started to ovulate. Still, there were no differences in endometrial immunostaining of AMH between ovulatory and anovulatory women with PCOS and controls, and no variation within the menstrual cycle. However, immunostaining of stromal AMH-R increased from cycle days 6-8 to 21-23 in all three groups. Furthermore, endometrial immunostaining of AMH-R correlated positively with oestrogen receptor alpha on cycle days 21-23 in the groups of women with PCOS, as well as in the controls (r = 0.66, P = 0.007 and r = 0.85, P < 0.001, respectively). CONCLUSIONS Although PCOS is associated with increased serum concentrations of AMH, protein expression of AMH and its receptor in the endometrium was no different to controls, and moreover not affected by lifestyle modification. These results imply that circulating AMH is not affecting expression of AMH and its receptor in the endometrium.