Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/5/2004
Publication Date: 11/1/2004
Citation: Zaniboni, L., Bakst, M.R. 2004. Aquaporins are observed in the duct epithelia of the epididymal region of the large white turkey. Poultry Science. 83:1917-1920. Interpretive Summary: We have little basic information on the production and maturation of sperm in birds. In the domestic turkey, sperm are transported out of the testes via an extensive and complex array of tubules collectively referred to as the excurrent ducts. One region of the excurrent ducts is the epididymal region. Here sperm mature and are concentrated by fluid resorption. Our study describes for the first time a mechanism for this fluid absorption. We located proteins known as aquaporins in the cells lining the tubules comprising the epididymal region. The aquaporins form channels which allow the movement of water across cells. This is the first time aquarporins have been reproted to be in birds. This information will be useful to other scientist doing work in the area of sperm function and sperm storage.
Technical Abstract: The cellular and molecular mechanisms regulating the re-uptake of the testicular fluid supporting sperm exiting the testes is not known in the bird. The presence of aquaporin, a protein involved in the transmembrane water transport, was investigated. Observations were limited to the ductuli efferentes, collecting ducts, and ductus epididymis. Interestingly all of these ducts were positive for aquaporins ¿2, -3, and ¿9 but not aquaporin-7. When positive, aquaporin was observed localized over the whole cell or the apical plasma membrane of the non-ciliated cells and the apical plasma membrane and cilia of the ciliated cells. This is the first study to clearly demonstrate the presence of aquaporins-2,-3, and ¿9 in the epididymal region of any bird. We assume the aquaporins play a role both in concentrating the sperm and in promoting sperm maturation in the epididymal region.