Biomaterial Database

Sodium-hydrogen exchange system in LLC-PK1 epithelium. 1987

A Moran

Sodium influx into LLC-PK1 cells has been characterized. The main amiloride-sensitive pathway for sodium entry through the apical membrane in this cell line is sodium-hydrogen exchange with an apparent Km for sodium of 19 mM. Influx is pH dependent and is amiloride sensitive with K1/2 of 30 microM. Inhibition of the sodium transport by protons (at 1 mM external sodium) is consistent with an interaction of H+ ions at a single site having an apparent pKH of 7.2. These data are similar to those reported previously for brush border membrane (BBM) isolated from kidney proximal tubule. However, in contrast to previously published reports, H+ does not compete with amiloride in blocking Na+ influx and exhibits a mixed inhibition with sodium ions. The latter, together with a direct and independent assessment of amiloride and sodium interaction, indicates that amiloride does not compete with sodium for the same site. Possible explanations for the discrepancy in the literature concerning the interaction of Na+, H+, and amiloride with the Na+-H+ exchanger and the characteristics of the Na+-H+ exchange system in LLC-PK1 are discussed.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D002352	Carrier Proteins	Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes.	Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D004848	Epithelium	The layers of EPITHELIAL CELLS which cover the inner and outer surfaces of the cutaneous, mucus, and serous tissues and glands of the body.	Mesothelium,Epithelial Tissue,Mesothelial Tissue,Epithelial Tissues,Mesothelial Tissues,Tissue, Epithelial,Tissue, Mesothelial,Tissues, Epithelial,Tissues, Mesothelial
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D000584	Amiloride	A pyrazine compound inhibiting SODIUM reabsorption through SODIUM CHANNELS in renal EPITHELIAL CELLS. This inhibition creates a negative potential in the luminal membranes of principal cells, located in the distal convoluted tubule and collecting duct. Negative potential reduces secretion of potassium and hydrogen ions. Amiloride is used in conjunction with DIURETICS to spare POTASSIUM loss. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p705)	Amidal,Amiduret Trom,Amiloberag,Amiloride Hydrochloride,Amiloride Hydrochloride, Anhydrous,Kaluril,Midamor,Midoride,Modamide,Anhydrous Amiloride Hydrochloride,Hydrochloride, Amiloride,Hydrochloride, Anhydrous Amiloride,Trom, Amiduret
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012964	Sodium	A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.	Sodium Ion Level,Sodium-23,Ion Level, Sodium,Level, Sodium Ion,Sodium 23
D017923	Sodium-Hydrogen Exchangers	A family of plasma membrane exchange glycoprotein antiporters that transport sodium ions and protons across lipid bilayers. They have critical functions in intracellular pH regulation, cell volume regulation, and cellular response to many different hormones and mitogens.	Na(+)-H(+)-Antiporter,Na(+)-H(+)-Exchanger,Sodium-Hydrogen Antiporter,Na(+)-H(+)-Antiporters,Na(+)-H(+)-Exchangers,SLC9 Na(+)-H(+) Exchangers,SLC9 Protein Family,SLC9 Proteins,SLC9-NHE Protein Family,Sodium-Hydrogen Antiporters,Sodium-Hydrogen Exchanger,Sodium-Proton Antiporter,Sodium-Proton Antiporters,Solute Carrier 9 Protein Family,Solute Carrier 9 Proteins,Antiporter, Sodium-Hydrogen,Antiporter, Sodium-Proton,Antiporters, Sodium-Hydrogen,Antiporters, Sodium-Proton,Exchanger, Sodium-Hydrogen,Exchangers, Sodium-Hydrogen,Protein Family, SLC9,Protein Family, SLC9-NHE,SLC9 NHE Protein Family,Sodium Hydrogen Antiporter,Sodium Hydrogen Antiporters,Sodium Hydrogen Exchanger,Sodium Hydrogen Exchangers,Sodium Proton Antiporter,Sodium Proton Antiporters