Localization of oestrogen receptors alpha and beta in human testis

Cellular localization of oestrogen receptor alpha (ERα) and beta (ERβ) proteins were studied in human testis samples using immunohistochemistry, and the expression of the corresponding mRNA was examined with reverse transcription-polymerase chain reaction (RT-PCR). Seven men, aged 28-48 years, who underwent diagnostic testicular biopsy because of azoospermia or to give spermatozoa for intracytoplasmic injection for infertility treatment, donated tissue for the study. One of them had anejaculation but normally functioning testes, and one was diagnosed as having Sertoli cell-only syndrome (SCOS). In addition, expression of ERβ protein was examined in one testis sample obtained from a man undergoing a sex change operation. Strong ERβ immunoreactivity was detected in the nuclei of spermatogonia, spermatocytes and early developing spermatids. Elongating spermatids, mature spermatozoa, Sertoli and Leydig cells were all negative for ERβ. The presence of ERβ protein was confirmed in Western analysis. With RT-PCR, both wild-type ERβ and ERβcx, the isoform which represses wild-type ER function, were easily detected. In most cases, ERβcx mRNA was more abundantly expressed than wild-type ERβ. The patient with SCOS expressed neither ERβ isoform. Neither ERα protein nor ERα mRNA was detected in any of the samples. We conclude that in the human testis, ERβ is likely to be the ER that mediates the effects of oestrogen.