title: Cortical Na+,K+-ATPase activity, abundance and distribution after in vivo renal ischemia without reperfusion in rats.
abstract: The aim of our work was to study the changes in activity, abundance and distribution of sodium, potassium-adenosine triphosphatase (Na+,K+-ATPase) in membranes of cortical tubular cells in an in vivo model of ischemic injury without reperfusion. Na+,K+-ATPase, alkaline phosphatase (AP) activities and their distribution in membranes isolated from renal cortex using a Percoll gradient were studied after different ischemic periods. Na+,K+-ATPase alpha-subunit protein abundance was analysed by Western-blot. Plasma urea and cortical adenosine 5' triphosphate (ATP) were also measured. In cortical homogenates 5 min of ischemia promoted a diminution in ATP content. Na+,K+-ATPase activity diminished after 40 min and AP after 100 min of ischemia. Na+,K+-ATPase activity in the Percoll gradient fractions after 5 min peaked at a higher density and was significantly decreased after 40 min. AP activity was decreased in typically enriched apical membranes after both times of ischemia. At each time studied Na+,K+-ATPase abundance was increased in cortical homogenates and membranes. Our results showed opposite effects of ischemia on Na+,K+-ATPase activity and abundance. Increased levels of Na+,K+-ATPase protein were observed. The enzyme would be rapidly delivered to membrane domains and become inactivated as ischemia persists.
authors.affiliation: Farmacología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, República Argentina. gcoux@fbioyf.unr.edu.ar
authors.forename: G
authors.initials: G
authors.lastname: Coux
authors.forename: L
authors.initials: L
authors.lastname: Trumper
authors.forename: M M
authors.initials: MM
authors.lastname: Elías
mesh_terms: D058186:Acute Kidney Injury / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000032:analysis; D000469:Alkaline Phosphatase / Q000032:analysis / Q000378:metabolism; D000818:Animals; D007511:Ischemia / Q000378:metabolism*; D007672:Kidney Cortex / Q000201:enzymology*; D007684:Kidney Tubules / Q000201:enzymology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis / Q000378:metabolism*; D013347:Subcellular Fractions / Q000201:enzymology; D014508:Urea / Q000097:blood
chemical_list: D000255:Adenosine Triphosphate; D014508:Urea; D000469:Alkaline Phosphatase; D000254:Sodium-Potassium-Exchanging ATPase