Mechanisms and functional role of intracellular pH regulation in hepatocytes.
Intracellular pH influences and is influenced by a diverse array of hepatocellular processes. It is regulated by the concerted action of three plasma membrane H+/HCO3- transporters that serve to buffer against both acidic (Na+/H+ exchange, Na+/HCO3- cotransport) and basic (Cl-/HCO3- exchange) metabolic challenges. The responsiveness of hepatocytes to these challenges is augmented by a regulatory interplay between pH-mediated changes in Vm and electrogenic Na+/HCO3- cotransport to maintain pHi and Vm within a range optimized to serve liver function. The cost is expenditure of metabolic energy to sustain increased activity of the Na+/K+ pump. The benefit is a dynamic servomechanism well-suited to the metabolic demands of hepatocytes, which may be found in future studies to be employed in other metabolically active epithelia as well.
Lidofsky
S D
SD
Department of Medicine, University of California, San Francisco.
Fitz
J G
JG
Scharschmidt
B F
BF
D000818:Animals; D001639:Bicarbonates / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008099:Liver / Q000378:metabolism*; D008564:Membrane Potentials; D012964:Sodium / Q000378:metabolism; D013816:Thermodynamics
D001639:Bicarbonates; D002712:Chlorides; D012964:Sodium