Differential expression of oestrogen receptor alpha and beta proteins in the testes and male reproductive system of human and non-human primates.

The role(s) oestrogens play in male adult reproductive function remains uncertain. We have used antibodies specific for oestrogen receptor- alpha (ERalpha) and - beta (ERbeta) to investigate their distribution within the male. In testes from adult human, macaque and marmoset, ERbeta protein was detected in Sertoli cells, Leydig cells and peritubular myoid cells. In germ cells, the intensity of immunostaining for ERbeta was variable between species. Immunoexpression in preleptotene, leptotene and zygotene spermatocytes was low/absent in all species. Elongated spermatids were consistently immunonegative. No ERalpha immunoexpression was detected in testes. ERbeta was detected in epithelial and stromal cell nuclei throughout the male reproductive system [efferent ductules (ED), epididymis, vas deferens, seminal vesicles] and in the bladder. ERalpha was detected in non-ciliated epithelial cells in the ED, but rarely in epithelial and basal cells within the epididymis. Epithelial cells from seminal vesicles and bladder were immunonegative for ERalpha. Expression of ERalpha in stromal cells was rare in the ED, epididymis and bladder but more frequent in seminal vesicles. Expression of ERalpha, and long and short forms of ERbeta, was confirmed by Western blotting. The widespread expression of ERbeta suggests that it is the primary target for modulation of tissue function via oestrogenic ligands in the male reproductive system.