Estrogen receptor alpha and beta expression in theca and granulosa cells from women with polycystic ovary syndrome.

A defining characteristic of dominant follicles is high estradiol concentrations. Abnormal expression of estrogen receptors (ERs) could contribute to poor follicular development and ovulatory failure in polycystic ovary syndrome (PCOS). The aim of this study was to determine whether there are differences in ERalpha and ERbeta expression in granulosa cells (GC) and theca cells (TC) from women with PCOS, compared with regularly cycling women. GC and TC were obtained by microdissection from 12 polycystic and 23 normal ovaries. ERalpha and ERbeta mRNA and protein expression were measured by semiquantitative RT-PCR and Western blot, respectively. In control ovaries, both GC and TC ERalpha mRNAs were higher in small antral (SA) than in dominant follicles. ERalpha mRNA was similar in PCOS and size-matched control follicles. In control follicles, ERalpha protein concentrations were higher in GC than in TC. In GC, the ERalpha concentrations were comparable among SA, dominant, and PCOS follicles. In TC, ERalpha concentrations were lower in dominant follicles but were markedly increased in PCOS. In control ovaries, GC and TC expression of ERbeta mRNA was higher in SA, compared with dominant follicles. In PCOS, ERbeta mRNA was intermediate between SA and dominant follicles in both GC and TC. In GC, the ERbeta protein concentrations followed the same pattern as mRNA expression; but in TC ERbeta, protein in PCOS was equivalent to that in dominant follicles. The results of this study demonstrate that there are significant alterations in the expression of ERalpha and ERbeta in PCOS that may be related to abnormal follicular development.