Estrogen agonists, 17beta-estradiol, bisphenol A, and diethylstilbestrol, decrease cortactin expression in the mouse testis.

Previous reports have revealed that estrogen agonists or anti-androgenic chemicals induce abnormal spermiogenesis in rodents. In the seminiferous epithelium, the apical ectoplasmic specialization (ES) is an actin-based (cell-cell) junctional structure developing between the Sertoli cells and spermatids as is the basal ES also--although it is located between adjoining Sertoli cells. In the apical and basal ES are several adhesion complex proteins that control the spermatid developing process. Cortactin, an actin-binding protein, is one of the ES adhesion proteins, combining with several cell-cell adhesions associating proteins. In the present study, 17beta-estradiol (E2, 1.2 microg/kg), bisphenol A (BPA, 2.4 microg/kg), and diethylstilbestrol (DES, 2.5 microg/kg) were subcutaneously injected in ICR 12-week-old male mice. Mice testes were observed for the expression of cortactin protein after E2, BPA, and DES treatments by Western blot analysis, immunohistochemical analysis, and immunoelectron microscopic analysis. Observations showed that the immunoreactivity of the treated testes was significantly decreased. The immunohistochemical reactivity of cortactin in the apical ES was decreased in the treated testis. In immunoelectron microscopic observations, ultrastructural immunolocalizations of cortactin protein in the apical ES by both E2 and BPA were decreased, and the immuno-gold particles of apical and basal ES by DES were much less than the control. In the toxicological field, cortactin may be considered to be one of the indicator proteins of abnormal spermiogenesis which is affected by exogenous chemicals, such as endocrine disrupting chemicals. In summary, this study helps toward understanding the cortactin protein expression underlying the histological abnormalities of spermatogenesis induced by exogenous hormonal chemical treatment.