On the role of Na,K-ATPase: a challenge for the membrane-pump and association-induction hypotheses.
The regulation of cellular ion levels has been an important issue of cell physiology since the beginning of the century. A special interest was focused on the monovalent ions which are involved in several cellular functions; in fact, the maintenance of high K+ level inside the cells is one of the most basic life-phenomena. Regarding the regulation of monovalent ions in general, two opposing ideas emerged: one being the membrane theory and the other the sorption theory(ies). Today most scientists are familiar only with the membrane theory which involves the pump and leak hypothesis and only a few consider the predictions of the association-induction hypothesis which may be classified as one of the sorption theories. In the regulation of monovalent ions the Na,K-ATPase is a key-molecule according to the membrane theory but not considered that important by the association-induction hypothesis. In this paper, we present two simple experiments which demonstrate the possible role of this molecule in the regulation of cellular Na+, K+ homeostasis and also disprove the pump and leak hypothesis.
Bogner
P
P
Department of Clinical Chemistry, University Medical School of Pécs, Hungary.
Nagy
E
E
Miseta
A
A
D000818:Animals; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism*; D006706:Homeostasis; D006736:Horses; D006801:Humans; D008954:Models, Biological; D011188:Potassium / Q000097:blood*; D012413:Rubidium / Q000097:blood; D012756:Sheep; D012964:Sodium / Q000097:blood*; D000254:Sodium-Potassium-Exchanging ATPase / Q000097:blood*
D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium; D011188:Potassium