Stereoselective inhibition of chloride transport by loop diuretics in pancreatic beta-cells.

The effects of loop diuretics on 36Cl- uptake was tested in isolated beta-cell-rich pancreatic islets. Bumetanide reduced the 36Cl- influx and the levorotatory form of ozolinone reduced both the influx and equilibrium content of 36Cl- in the islets, whereas the dextrorotatory form was largely inactive. The data suggest that the beta-cells are equipped with a loop diuretic-sensitive system for 36Cl- uptake and that this system is confined to a sterically well-defined structure.