Differential expression of estrogen receptor-α and -β and androgen receptor in the ovaries of marmosets and humans

Estrogens and androgens are essential for the maturation of the ovarian follicle and normal fertility in the female. We have used antibodies specific for both forms of estrogen receptor (alpha [ER alpha] and beta [ER beta]) and androgen receptor (AR) to investigate the pattern of receptor expression in ovaries obtained from women and from a New World primate, the Common marmoset (Callthrix jacchus). On Western blots, three antibodies directed against different peptides within human ER beta all recognized recombinant human (h) ER beta but did not bind to recombinant hER alpha. The ER beta protein was extracted from human ovary and prostate and marmoset ovary. In marmoset and human ovaries, ER beta protein was detected in the nuclei of granulosa cells in all sizes of follicle (both before and after formation of the antrum), and it was also detected in thecal cells, corpora lutea, surface epithelium, and stroma. In contrast, ER alpha protein was not detected in the nuclei of granulosa cells in preantral follicles, was low/absent from stromal and thecal cells, but was expressed in granulosa cells of antral follicles and in the surface epithelium. The pattern of expression of AR protein more closely resembled that of ER beta than ER alpha. In conclusion, three independent antibodies have demonstrated convincingly that ER beta is expressed in a wide range of cells in the primate ovary. Granulosa cells in preantral follicles could contain ER beta:beta dimers. In antral follicles, however, ER alpha is also expressed, and the formation of homo- or heterodimers containing ER alpha may influence the pattern of gene activation within these cells.