Photoperiod-dependent capability of androgen aromatization and the role ofestrogens 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' actio n. 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 rece ptors, 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 somatic cells while ge rm cell did not express any immunoreaction. Moreover, the ability to conver t androgens to estrogens by various testicular cells was documented; aromat ase immunoexpression was found in testis sections, not only in Leydig cells and Sertoli cells but also in germ cells. Finally, the expression of estro gen receptor-alpha (ER alpha) was observed in Leydig cells whereas the pres ence of estrogen receptor-beta (ER beta) was detected in Sertoli and germ c ells, namely spermatocytes and spermatids. The cellular distribution of and rogen receptors appeared to be light -and age-dependent in adults; immunoex pression of aromatase and ER beta was found to be both age -and photoperiod -dependent in germ cells. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.