title: Effect of extracellular potassium on the transport of sodium and potassium in rat thymocytes.
abstract: 1. The effect of extracellular potassium on the transport of sodium and potassium in rat thymocytes has been studied in vitro. 2. A significant increase in the rate constant for total and ouabain-sensitive sodium efflux was demonstrated at an extracellular potassium concentration of 1 mmol/l as compared with that at either 0 or 2 mmol/l. 3. At potassium concentrations below 3 mmol/l ouabain-sensitive sodium influx was observed suggesting sodium-sodium exchange catalysed by the sodium pump. 4. Both total and ouabain-insensitive potassium efflux rose with external potassium. A small ouabain-sensitive potassium efflux was observed at all levels of external potassium studied. 5. Total and ouabain-insensitive potassium influx increased with external potassium, but did not appear to saturate. Ouabain-sensitive potassium influx reached a maximum at an external potassium concentration of 2 mmol/l then decreased with increasing external potassium.
mesh_terms: D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D066298:In Vitro Techniques; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism*; D014867:Water / Q000378:metabolism
chemical_list: D014867:Water; D010042:Ouabain; D012964:Sodium; D011188:Potassium