Monoclonal antibody localization of Na+-K+-ATPase in the exocrine pancreas and parotid of the dog.
A monoclonal antibody specific to the beta-subunit of the canine Na+-K+-ATPase has been characterized and used to directly localize the enzyme in thin frozen sections of dog pancreas and parotid. The antibody, 7-2M, recognizes only the beta-subunit of the sodium pump as determined by immunoprecipitation and immunoblot and is not directed against an oligosaccharide determinant. 7-2M immunolocalizes to the same cellular and subcellular domains of renal tubular cells as do other, previously characterized, antibodies directed to the alpha-subunit of the sodium pump. In the pancreas the preponderance of the Na+-K+-ATPase is found on the basolateral membranes of centroacinar and intralobular duct cells. Interlobular duct cells also express a large component of basolaterally located enzyme, although comparatively little pump is seen on acinar cells. In the parotid a large amount of Na+-K+-ATPase is seen on the striated duct cells, with high levels also noted on cells of the intercalated ducts and serous demilunes. Again the acinar cells show comparatively low levels of Na+-K+-ATPase. In no instance is Na+-K+-ATPase found on the apical membranes of pancreas or parotid cells. These data suggest that Na+-K+-ATPase, located on the basolateral plasmalemma of duct-derived cells, may be involved in water and electrolyte secretion from the pancreas and parotid.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D004285:Dogs; D007158:Immunologic Techniques; D007473:Ion Channels / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008854:Microscopy, Electron; D010179:Pancreas / Q000201:enzymology* / Q000648:ultrastructure; D010306:Parotid Gland / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D007473:Ion Channels; D000254:Sodium-Potassium-Exchanging ATPase