Evidence for co-transport of sodium, potassium and chloride in mouse pancreatic islets.
1. The presence of a loop diuretic-sensitive co-transport system for Na+, K+ and Cl- was tested in isolated pancreatic islets. 2. Substitution of Cl- with the impermeant anion isethionate or addition of frusemide both reduced the ouabain-resistant islets uptake of 86Rb+ (K+ marker) without affecting the ouabain-sensitive uptake or equilibrium content of 86Rb+. The effects of Cl- substitution and frusemide were overlapping. 3. D-Glucose reduced the ouabain-resistant islets uptake of 86Rb+. This effect was additive to the effect of Cl- substitution or frusemide. 4. Substitution of Cl- with isethionate or addition of frusemide both reduced the efflux of 86Rb+ from the islets. These effects were additive to the reduction of 86Rb+ efflux induced by D-glucose. 5. Substitution of K+ or Na+ with choline reduced the equilibrium content of 36Cl- in the pancreatic islets. 6. These data are compatible with the operation in the pancreatic beta-cells of a loop diuretic-sensitive co-transport system for Na+, K+ and Cl-, that may serve as an inwardly directed Cl- pump.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002712:Chlorides / Q000493:pharmacokinetics*; D002794:Choline / Q000494:pharmacology; D005665:Furosemide / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D066298:In Vitro Techniques; D007513:Isethionic Acid / Q000493:pharmacokinetics; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D011188:Potassium / Q000493:pharmacokinetics*; D012414:Rubidium Radioisotopes; D012964:Sodium / Q000493:pharmacokinetics*
D002712:Chlorides; D012414:Rubidium Radioisotopes; D005665:Furosemide; D007513:Isethionic Acid; D012964:Sodium; D005947:Glucose; D002794:Choline; D011188:Potassium