Na(+)- and anion-dependent Mg2+ influx in isolated hepatocytes.
Hepatocytes, which were Mg(2+)-depleted during isolation, took up Mg2+ during reincubation. Mg2+ uptake was dependent on the concentration of extracellular Mg2+, Na+, Cl-, bicarbonate and phosphate. Li+ and choline+ did not substitute for extracellular Na+ in Mg2+ influx. Mg2+ influx was maximal when all three anion species were present, and did not occur when these anions were replaced by gluconate. Bicarbonate, phosphate and Cl- could substitute for each other. Mg2+ uptake in hepatocytes was inhibited by p-chloromercuribenzene sulfonate, ouabain, gramicidin D, amiloride and verapamil. The results were explained by the assumption that net Mg2+ influx in hepatocytes is operating via electroneutral Na+, Mg2+/anion cotransport driven by the Na+ gradient. However, electrogenic Mg2+ uptake gated by extracellular Na+ and anions could not be excluded.
Günther
T
T
Institute of Molecular Biology and Biochemistry, Free University of Berlin, Germany.
Höllriegl
V
V
D002731:4-Chloromercuribenzenesulfonate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D002712:Chlorides / Q000494:pharmacology; D066298:In Vitro Techniques; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008274:Magnesium / Q000378:metabolism* / Q000494:pharmacology; D010477:Perfusion; D010710:Phosphates / Q000494:pharmacology; D051381:Rats; D012964:Sodium / Q000494:pharmacology*
D001639:Bicarbonates; D002712:Chlorides; D010710:Phosphates; D002731:4-Chloromercuribenzenesulfonate; D000255:Adenosine Triphosphate; D012964:Sodium; D008274:Magnesium