Photoperiod-dependent capability of androgen aromatization and the role of estrogens in the bank vole testis visualized by means of immunohistochemistry.

Detection of steroid hormone receptors within a target tissue is important for an understanding of their crucial role in regulating of steroids' action. In the light of recent knowledge on the role of estrogens in male gonads the efforts were undertaken to clarify and discuss a role of androgen receptors, aromatase and estrogen receptors (ER) in mediating testosterone and/or estradiol action in testicular cells of bank voles that were kept under short or long light cycles. Immunohistochemistry was performed on paraplast embedded sections of the bank vole testes. First, androgen receptors were immunolocalized in testicular somatic cells while germ cell did not express any immunoreaction. Moreover, the ability to convert androgens to estrogens by various testicular cells was documented; aromatase immunoexpression was found in testis sections, not only in Leydig cells and Sertoli cells but also in germ cells. Finally, the expression of estrogen receptor-alpha (ERalpha) was observed in Leydig cells whereas the presence of estrogen receptor-beta (ERbeta) was detected in Sertoli and germ cells, namely spermatocytes and spermatids. The cellular distribution of androgen receptors appeared to be light -and age-dependent in adults; immunoexpression of aromatase and ERbeta was found to be both age -and photoperiod-dependent in germ cells.