K+ depletion and Na+ pump density.
D001693:Biological Transport, Active; D006367:HeLa Cells / Q000201:enzymology; D006801:Humans; D011188:Potassium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium