Coordinated regulation of Na/H exchange and [K-Cl] cotransport in dog red cells
Swelling-activated [K-Cl] cotransport and shrinkage-activated Na/H exchange were studied in dog red cells with altered internal Mg or Li content. The two pathways responded in a coordinated fashion. When cells were depleted of Mg, [K-Cl] cotransport was stimulated and Na/H exchange was inhibited. Raising internal Mg had the opposite effect: [K-Cl] cotransport was inhibited and Na/H exchange was stimulated. Li loading, previously shown to stimulate Na/H exchange, inhibited [K-Cl] cotransport. From these reciprocal effects and from other evidence, we surmise that the regulation of Na/H exchange and [K-Cl] cotransport is conducted and coordinated by a discrete mechanism that responds to changes in cell volume and is sensitive to cytoplasmic Mg and Li concentrations.
Author contributions ::: ::: GH helped design the study, establish the animal model, collect and analyze samples, and write the manuscript. YY and DH helped establish the animal model, performed Western blotting, immunohistochemistry analyses. YY and DH also helped analyse data and revise the manuscript. QYW and JK contributed to study planning, analyse and interpret data, review and revise the manuscript. All authors have approved the final version of this article to be published and agreed to be accountable for all aspects of the work in ensuring the questions related to the accuracy or integrity of any part of the work. ::: ::: ::: ::: Disclosure ::: ::: The authors report no conflicts of interest in this work.