LOCALIZATION OF NA-ATPASE IN TISSUES OF RABBIT AND TELEOSTS USING AN ANTISERUM DIRECTED AGAINST A PARTIAL SEQUENCE OF THE ALPHA-SUBUNIT(, K+)

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