title: The ultrastructural localization of transport ATPase in the rat liver at non-bile canalicular plasma membranes.
abstract: Na,K-ATPase in rat livers was localized cytochemically at the ultrastructural level. The Ernst technique, a method using p-nitrophenylphosphate (pNPP) substrate, was used to demonstrate ouabain-sensitive, K-dependent phosphatase, an enzyme of the Na,K-ATPase reaction sequence. Reaction product was localized predominantly on the sinusoidal and non-bile canalicular (intercellular) surfaces. This localization contrasts with previous histo-chemical studies using ATP substrate and with models that have considered the transport enzyme to be localized at the canalicular surface. If Na,K-ATPase is of importance in bile salt independent flow, a significant presence of the enzyme at sites other than the canalicular membrane suggests that a paracellular movement of sodium and water into the canaliculus must be considered.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D006651:Histocytochemistry; D008099:Liver / Q000201:enzymology* / Q000648:ultrastructure; D008274:Magnesium; D008297:Male; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
chemical_list: D000251:Adenosine Triphosphatases; D000254:Sodium-Potassium-Exchanging ATPase; D008274:Magnesium