Regulation of renal Na(+),K(+)-ATPase and ouabain-sensitive H(+),K(+)-ATPase by the cyclic AMP-protein kinase A signal transduction pathway.
We investigated the effect of the cyclic AMP-protein kinase A (PKA) signalling pathway on renal Na(+),K(+)-ATPase and ouabain-sensitive H(+),K(+)-ATPase. Male Wistar rats were anaesthetized and catheter was inserted through the femoral artery into the abdominal aorta proximally to the renal arteries for infusion of the investigated substances. Na(+),K(+)-ATPase activity was measured in the presence of Sch 28080 to block ouabain-sensitive H(+),K(+)-ATPase and improve specificity of the assay. Dibutyryl-cyclic AMP (db-cAMP) administered at a dose of 10(-7) mol/kg per min and 10(-6) mol/kg per min increased Na(+),K(+)-ATPase activity in the renal cortex by 34% and 42%, respectively, and decreased it in the renal medulla by 30% and 44%, respectively. db-cAMP infused at 10(-6) mol/kg per min increased the activity of cortical ouabain-sensitive H(+),K(+)-ATPase by 33%, and medullary ouabain-sensitive H(+),K(+)-ATPase by 30%. All the effects of db-cAMP were abolished by a specific inhibitor of protein kinase A, KT 5720. The stimulatory effect on ouabain-sensitive H(+),K(+)-ATPase and on cortical Na(+),K(+)-ATPase was also abolished by brefeldin A which inhibits the insertion of proteins into the plasma membranes, whereas the inhibitory effect on medullary Na(+),K(+)-ATPase was partially attenuated by 17-octadecynoic acid, an inhibitor of cytochrome p450-dependent arachidonate metabolism. We conclude that the cAMP-PKA pathway stimulates Na(+),K(+)-ATPase in the renal cortex as well as ouabain-sensitive H(+),K(+)-ATPase in the cortex and medulla by a mechanism requiring insertion of proteins into the plasma membrane. In contrast, medullary Na(+),K(+)-ATPase is inhibited by cAMP through a mechanism involving cytochrome p450-dependent arachidonate metabolites.
Bełtowski
Jerzy
J
Department of Pathophysiology, Medical University, Lublin, Poland. patfiz@asklepios.am.lublin.pl
Marciniak
Andrzej
A
Wójcicka
Grazyna
G
Górny
Dionizy
D
D000818:Animals; D020126:Brefeldin A / Q000494:pharmacology; D003994:Bucladesine / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D017506:H(+)-K(+)-Exchanging ATPase / Q000378:metabolism*; D007093:Imidazoles / Q000494:pharmacology; D007668:Kidney / Q000201:enzymology*; D007672:Kidney Cortex / Q000201:enzymology; D007679:Kidney Medulla / Q000201:enzymology; D008297:Male; D010042:Ouabain / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D004791:Enzyme Inhibitors; D005231:Fatty Acids, Unsaturated; D007093:Imidazoles; C035235:Sch 28080; D020126:Brefeldin A; C047008:17-octadecynoic acid; D010042:Ouabain; D003994:Bucladesine; D017868:Cyclic AMP-Dependent Protein Kinases; D017506:H(+)-K(+)-Exchanging ATPase; D000254:Sodium-Potassium-Exchanging ATPase