Hydrogen ion cotransport by the renal brush border glutamate transporter

Biochemistry. 1983 Nov 8;22(23):5459-63. doi: 10.1021/bi00292a030.

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Biological Transport, Active
  • Glutamates / metabolism*
  • Glutamic Acid
  • Hydrogen / metabolism*
  • Hydrogen-Ion Concentration
  • Kidney Cortex / ultrastructure*
  • Microvilli / metabolism
  • Potassium / metabolism
  • Rabbits
  • Sodium / metabolism
  • Time Factors

Substances

  • Glutamates
  • Glutamic Acid
  • Hydrogen
  • Sodium
  • Potassium