Differential expression of oestrogen receptor α and β 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 (ER alpha) and -beta (ERP) to investigate their distribution within the male, In testes from adult human, macaque and marmoset, ER beta protein was detected in Sertoli cells, Leydig cells and peritubular myoid cells. In germ cells, the intensity of immunostaining for ER beta was variable between species, Immunoexpression in preleptotene, leptotene and zygotene spermatocytes was low/absent in all species, Elongated spermatids were consistently immunonegative. No ER alpha immunoexpression was detected in testes, ER beta 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, ER alpha 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 ER alpha, Expression of ER alpha in stromal cells was rare in the ED, epididymis and bladder but more frequent in seminal vesicles. Expression of ER alpha, and long and short forms of ER beta, was confirmed by Western blotting. The widespread expression of ER beta suggests that it is the primary target for modulation of tissue function via oestrogenic ligands in the male reproductive system.