Occurrence and cellular distribution of estrogen receptors ERα and ERβ in the testis and epididymal region of roosters.

Estrogen signaling is required for the maintenance of male reproductive function and is mediated by the estrogen receptors ERα and ERβ. These receptors are widely distributed in mammalian reproductive tissues, but information is limited in non-mammalian species including birds. The aim of this study was to investigate the occurrence and cellular distribution of ERα and ERβ in the testis and epididymal region of roosters. The results showed for the first time that ERβ was the predominant receptor detected in the testis, being expressed in the somatic and some germ cells. Within the epididymal region, ERβ was strongly expressed in all segments, whereas the most intense reaction for ERα was found in the distal efferent ductules. The differential expression of ERα and ERβ within the rooster testis and epididymal region suggests that these organs may be a target for different actions of estrogen.