title: Differential effect of extracellular calcium on the Na(+)-K+ pump activity in intact polymorphonuclear leucocytes and erythrocytes.
abstract: The effect of extracellular calcium on the Na(+)-K+ pump activity in human polymorphonuclear leucocytes and erythrocytes was studied and compared with the activity in mixed peritoneal leucocytes from rats. While there was maximal decrease in the pump activity (25-30%) of leucocytes from both rat and human by calcium 0.6 mM, a concentration of 0.1 mM caused a substantial decrease indicating a high sensitivity for extracellular calcium. In contrast, calcium had no effect on the pump activity in erythrocytes. The effect of calcium on the pump activity in leucocytes may be due to regulation of the influx of sodium across the plasma membrane, since in human leucocytes calcium had no effect on the pump activity if the cells were loaded with sodium.
authors.affiliation: Department of Pharmacology, Odense University, Denmark.
authors.forename: R H
authors.initials: RH
authors.lastname: Petersen
authors.forename: T
authors.initials: T
authors.lastname: Knudsen
authors.forename: T
authors.initials: T
authors.lastname: Johansen
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002352:Carrier Proteins / Q000187:drug effects*; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000378:metabolism; D028021:Sodium-Potassium-Chloride Symporters
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D028021:Sodium-Potassium-Chloride Symporters; D012964:Sodium; D011188:Potassium; D002118:Calcium