Peritubular Na-K exchange ion pump in maleate-treated frog kidney proximal tubular cells.
1. After perfusion of isolated frog kidneys for 1 hr with 10(-3) or 10(-2) M maleate Ringer, the peritubular membrane potential gradually declined in a dose-dependent manner. 2. The ouabain-like effects of maleate on cell Na and K activities were dose-dependent and smaller than the effects of zero K or 10(-4) M ouabain. Intracellular pH was not altered in the presence of 10(-2) M maleate. 3. The driving force for Na entry into the cell was reduced, respectively, to 81.4 and 58.4% (of control) in the presence of 10(-3) and 10(-2) M maleate. 4. There was no histochemically detectable inhibition of proximal tubule Na-K ATPase activity during 3 hr of perfusion with 10(-2) M maleate.
Cemerikić
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D
Department of Pathological Physiology, Faculty of Medicine, Dr Subotica 1/II, Beograd, Yugoslavia.
Filipović
D
D
Milovanović
S
S
Petrović
S
S
Cvetković
D
D
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects; D005260:Female; D006651:Histocytochemistry; D066298:In Vitro Techniques; D007474:Ion Exchange; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D008298:Maleates / Q000494:pharmacology*; D008839:Microelectrodes; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism* / Q000494:pharmacology; D011893:Rana esculenta; D012964:Sodium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D008298:Maleates; D010042:Ouabain; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium