Na+/H+ exchange in the kidneys of eels (Anguilla anguilla) adapted to sea water or to freshwater environments: Studies with brush border membrane vesicles

1. 1. In brush border membrane vesicles isolated from eel kidneys, adapted either to sea water or freshwater environments, a Na + /H + antiporter is present. 2. 2. Using a calibration plot it is possible to evaluate the amount of protons that this antiporter can accumulate inside the vesicular space. 3. 3. The activity of the antiporter seems to be affected by the salinity of the water; it is higher in animals adapted to seawater. 4. 4. This adaptation seems to occur by a J max regulation of the antiporter.