The presence of androgen receptors in the epididymis and prostate of the stallion and cryptorchid horse--a preliminary study.

Distribution of androgen receptors (ARs) in the epididymal duct and prostate of three entire stallions and one bilaterally cryptorchid horse was studied immunohistochemically using a polyclonal rabbit antiserum against the ARs. In both the healthy stallions and the cryptorchid, the epithelial cells of the epididymides showed nuclear staining for ARs. The intensity of AR-staining in the principal cells of the epididymis was stronger than that of the basal cells. In the prostate, the glandular secretory cells were moderately stained whereas the basal cells expressed weak AR-staining. Immunostaining for ARs in the reproductive tissues of the cryptorchid horse was always stronger than in those of the stallions. Our results demonstrate for the first time the AR localisation to equine epididymal and prostatic cells, which are directly regulated by androgens.