Localization of Na , K -ATPase in Tissues of Rabbit and Teleosts Using an Antiserum Directed Against a Partial Sequence of the α-Subunit

A specific polyclonal antibody against Na+, K(+)-ATPase alpha-subunit was developed using a synthetic oligopeptide as antigen. By Western blot analysis under non-reducing conditions, this antibody recognized a protein band of approximately 150 kDa corresponding to the intact form (alpha beta-complex) of Na+, K(+)-ATPase in rabbit kidney. Furthermore, this antibody recognized a 150 kDa protein band corresponding to the intact form of Na+, K(+)-ATPase and some bands of about 60-65 kDa corresponding to fragments of the alpha-subunit in gill and kidney of masu salmon. This antibody did not recognize the alpha-subunit under reducing conditions. By immunohistochemical analysis, cells immunoreactive with this antibody were observed in renal tubular epithelial cells in kidney sections of rabbit, masu salmon, eel and rockfish. In addition, large spherical eosinophilic cells in gills of masu salmon, eel and rockfish were immunoreactive with the antibody. It is likely that these immunoreactive cells correspond to gill chloride cells. These data indicate that this antibody is a useful tool for studying changes in and the function of Na+, K(+)-ATPase during osmoregulatory adaptation in a variety of fish species.