ERβ1 and the ERβ2 Splice Variant (ERβcx/β2) Are Expressed in Distinct Cell Populations in the Adult Human Testis

• Published in: The journal of clinical endocrinology and metabolism 2002-06, Vol.87 (6), p.2706-2715
• Main Authors: Saunders, Philippa T. K., Millar, Michael R., Macpherson, Sheila, Irvine, D. Stewart, Groome, Nigel P., Evans, Lee R., Sharpe, Richard M., Scobie, Graeme A.
• Format: Article
• Language: English
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jcem.87.6.8619

Estrogens can regulate germ cell function. Estrogen action is mediated via high affinity ERs; two subtypes (ERα and ERβ) have been identified. We have shown previously that ERβ is expressed in nuclei of multiple human testicular cells. A variant isoform of human (h) ERβ (hERβcx/2), formed by alternative splicing, has been identified in testicular cDNA libraries by two laboratories. The present study examined the expression of wild-type (ERβ1) and variant (ERβ2) β receptors in human testes by 1) RT-PCR with isoform specific primers, and 2) single and double immunohistochemistry using monoclonal antibodies raised against peptides unique to the C termini of hERβ1 and hERβ2. PCR products specific for ERβ1 and ERβ2 were amplified from cDNA pools prepared from human testes and granulosa cells. On Western blots, the anti-ERβ1 monoclonal antibody bound to recombinant ERβ1 and the anti-ERβ2 monoclonal to recombinant hERβ2. Neither bound to the other ERβ isoform nor to recombinant ERα. ERβ1 and ERβ2 proteins were both detected in human testis. Immunoexpression of ERβ1 was most intense in pachytene spermatocytes and round spermatids, whereas low levels of expression were detected in Sertoli cells, spermatogonia, preleptotene, leptotene, zygotene, and diplotene spermatocytes. Highest levels of expression of ERβ2 protein were detected in Sertoli cells and spermatogonia with low/variable expression in preleptotene, pachytene, and diplotene spermatocytes. No immunostaining was detected in elongating spermatids. Most interstitial cells expressed more ERβ2 than ERβ1. It is speculated that the cells most susceptible to modulation by estrogenic ligands are round spermatids in which levels of expression of ERβ1 are high. In contrast, expression of ERβ2, an isoform that may act as a dominant negative inhibitor of ER action, in Sertoli cells and spermatogonia, could protect these cells from adverse effects of estrogens.