EXPRESSION OF ESTROGEN-RECEPTOR-BETA (ER-BETA) OCCURS IN MULTIPLE CELL-TYPES, INCLUDING SOME GERM-CELLS, IN THE RAT TESTIS

The identification of a second oestrogen receptor (beta) has prompted a re-evaluation of the potential sites of action of oestrogens. The ai m of the present study was to characterise immunoexpression of ER beta expression in the testis to complement earlier data which had demonst rated that expression of ER alpha is confined to testicular interstiti al Leydig cells. In all testes studied, including those from both feta l (day 20.5 p.c.) and adult rats, ER beta was found to be expressed in multiple cell types. Sertoli cell nuclei were immunopositive at all a ges. In adult testes expression in Sertoli cells was not stage depende nt and was unaffected by ablation of Leydig cells. In fetal testes ER beta was also expressed in peritubular cells, fetal Leydig cells and g onocytes. In the pubertal and adult testis ER beta was detected in the nuclei of spermatogonia and most pachytene spermatocytes. Weak immuno positive staining was present in the cytoplasm of spermatocytes underg oing the second meiotic division. In conclusion the widespread express ion of ER beta in the testis is consistent with a role for oestrogens in modulating spermatogenesis, and hence fertility, in the male.