Loss of LH-induced down-regulation of anti-Müllerian hormone receptor expression may contribute to anovulation in women with polycystic ovary syndrome.

STUDY QUESTION: Are anti-Müllerian hormone (AMH) and AMH type II receptor (AMHR-II) mRNAs similarly regulated by gonadotrophins in lutein granulosa cells (GCs) from control, normo-ovulatory and oligo/anovulatory women with polycystic ovary syndrome (PCOS)? SUMMARY ANSWER: AMH mRNA expression was induced by LH only in lutein GC of oligo/anovulatory PCOS women; down-regulation of AMHR-II, induced by LH in control and normo-ovulatory PCOS women, was absent in oligo/anovulatory women. WHAT IS KNOWN ALREADY: It was suggested that AMH could be responsible for the blockade of follicles at the small antral stage in PCOS women. In keeping with this hypothesis, both AMH and AMHR-II are overexpressed in lutein GCs from oligo/anovulatory PCOS women. STUDY DESIGN, SIZE, DURATION: Women undergoing IVF were included in this prospective study, either in the control group (30 women) or in the PCOS group (21 normo-ovulatory and 19 oligo/anovulatory patients) between January 2010 and July 2012. PARTICIPANTS/MATERIALS, SETTING,
METHODS: Human lutein GCs were isolated from follicular fluid during IVF protocols. Twenty-four hours after seeding, lutein GCs from each woman were serum starved and cultured for 48 h ± FSH, LH or cAMP. Then AMH and AMHR-II mRNAs were quantified by quantitative RT-PCR and AMH protein concentration was measured in the culture medium by ELISA. Experimental results were analyzed, within each group of women, by the non-parametric Wilcoxon test for paired comparisons between cells cultured in control medium and FSH, LH or cAMP treated cells. Clinical comparisons between the three groups of women were performed on log values using the ANOVA test with Bonferroni correction. MAIN RESULTS AND THE ROLE OF CHANCE: FSH up-regulated both AMH expression and secretion by lutein GCs from the three groups of women (P < 0.05). LH had no effect on AMH mRNAs levels in lutein GCs from controls and normo-ovulatory PCOS women, but increased AMH expression in oligo/anovulatory PCOS women (P < 0.05). Interestingly, LH and cAMP treatments reduced AMHR-II expression by lutein GCs from controls and normo-ovulatory PCOS women (P < 0.05), but had no effect on AMHR-II mRNA levels in oligo/anovulatory PCOS women. LIMITATIONS, REASONS FOR CAUTION: The lutein GCs are not the best model to study AMH and AMHR-II regulation by gonadotrophins. Indeed, AMH and AMHR-II are down-regulated in luteinized cells. Furthermore, these cells have been exposed to non-physiological levels of gonadotrophins and hCG. However, AMH and AMHR-II mRNAs are quantifiable by real-time RT-PCR, and the cells are still responsive to FSH and LH. The age of patients is significantly different between control and oligo/anovulatory PCOS women: this may be a bias in the interpretation of results but older women in the control group had a good ovarian reserve. WIDER IMPLICATIONS OF THE
FINDINGS: The overexpression of AMH and AMHR-II in oligo/anovulatory PCOS women could be due to increased LH levels and/or inhibition of its repressive action. The fact that this dysregulation is observed in oligo/anovulatory, but not in normo-ovulatory, PCOS women emphasizes the role of LH in the follicular arrest of PCOS women and suggests that this involves the AMH/AMHR-II system. STUDY FUNDING/COMPETING INTEREST(S): The Assistance-Publique Hôpitaux de Paris provided a Contrat d'Interface and the Agence de Biomédecine provided a grant to Nathalie di Clemente. Schering-Plough provided an FARO grant to Alice Pierre. The authors have nothing to disclose.