title: Hydrogen ion cotransport by the renal brush border glutamate transporter.
abstract: Sodium ion dependent glutamate transport into rabbit renal brush border membrane vesicles is stimulated by low external pH and inhibited by low internal pH. Imposition of a pH difference (delta pH) (interior alkaline) across the vesicle membrane drives glutamate accumulation in the absence of other driving forces. This process requires Na+ but is not due to generation of an Na+ gradient in response to delta pH. Internal K+ stimulates both the rate and extent of glutamate accumulation, although K+ is not absolutely required for transport. Internal H+ inhibits the rate of glutamate accumulation by decreasing this K+ stimulation. Conversely, external K+ inhibits glutamate influx, and this inhibition can be overcome by lowering the external pH. These results indicate that H+ is cotransported with glutamate and suggest the possibility that, in the absence of internal K+, H+ can also fulfill the requirement for a countertransported ion.
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D005971:Glutamates / Q000378:metabolism*; D018698:Glutamic Acid; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007672:Kidney Cortex / Q000648:ultrastructure*; D008871:Microvilli / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D011817:Rabbits; D012964:Sodium / Q000378:metabolism; D013997:Time Factors
chemical_list: D005971:Glutamates; D018698:Glutamic Acid; D006859:Hydrogen; D012964:Sodium; D011188:Potassium