Immunolocalization, regulation and postnatal expression of aquaporins 1, 8 and 9 in the testis, efferent ducts and epididymis of adult rats

Aquaporins (AQPs) are membrane protein channels that allow rapid passage of water through an epithelium containing tight junctions. In the present study, light and electron microscope immunocytochemistry were utilized to localize several members of the aquaporin family in the testis, efferent ducts and epididymis of adult animals, animals at different postnatal ages and efferent duct ligated and orchidectomized animals with or without testosterone supplementation. In adult animals, AQP-8 expression was noted exclusively in the testis where it outlined Sertoli cells of the seminiferous epithelium. AQP-9 expression in the testis was seen to outline the periphery of Leydig cells but not cells of the seminiferous epithelium. AQP-9 was also mainly expressed in the apical cytoplasm of the nonciliated cells of the efferent ducts corresponding in the electron microscope to labelling of early endocytic structures. (Abstract shortened by UMI.).