• estrogens;
  • estrogen receptors;
  • testis;
  • pig development


High affinity estrogen receptors (ERs) mediate estrogen action in male reproductive tissues. The objective of the present study was the immunolocalization of estrogen receptor α and estrogen receptor β in immature and mature testes of pig, a species in which the role of estrogens on gonadal function is scarcely known. Testes from 3 and 18 month-old pigs were investigated. Immunohistochemistry was performed on paraffin embedded-tissues using both mouse anti-human monoclonal IgG ERα and IgG ERβ 1 isoform. Western blot analysis demonstrated antibody specificity. ERα staining was not observed in immature testes, but it was detected in spermatogonia, spermatocytes and in the most Leydig cells of mature testes. ERβ immunoreactivity was observed in spermatogonia and Leydig cells of immature gonads, while it was clearly detected in spermatogonia and in spermatocytes of adult pig testes. The differential ERα/ERβ expression in germ and somatic cells of the gonads suggest a role of estrogens in function and in development of pig testis. © 2004 Wiley-Liss, Inc.