Localization of S-100 proteins in the testis and epididymis of poultry and rabbits.

The present investigation was conducted to demonstrate S-100 protein in the testis and epididymis of adult chickens, Sudani ducks, pigeons, and rabbits. This study may represent the first indication for the presence of S-100 in the male reproductive organs of these species and might therefore serve as a milestone for further reports. In the testis of chickens, pigeons and rabbits, intense S-100 was seen in Sertoli cells. S-100 was also seen in the endothelial lining of blood vessels in rabbit testis. On the contrary, no S-100 reaction was detected in the Sertoli cells of Sudani ducks. In epididymis, the localization of S-100 had varied according to species studied; it was seen in the basal cells (BC) of epididymal duct in duck, non-ciliated cells of the distal efferent ductules in pigeons and ciliated cells of the efferent ductules and BC of rabbit epididymis. Conversely, S-100 specific staining was not detected in the epithelial lining of the rooster and pigeon epididymal duct as well as the principal cells of the rabbit epididymis. In conclusion, the distribution of the S-100 proteins in the testis and epididymis might point out to its roles in the male reproduction.