A proton gradient, not a sodium gradient, is the driving force for active transport of lactate in rabbit intestinal brush-border membrane vesicles

Academic Article

Abstract

  • An inward-directed H+ gradient markedly stimulated lactate uptake in rabbit intestinal brush-border membrane vesicles, and uphill transport against a concentration gradient could be demonstrated under these conditions. Uptake of lactate was many-fold greater in the presence of a H+ gradient than in the presence of a Na+ gradient. Moreover, there was no evidence for uphill transport of lactate in the presence of a Na+ gradient. The H+-gradient-dependent stimulation of lactate uptake was not due to the effect of a H+-diffusion potential. The uptake process in the presence of a H+ gradient was saturable [K(t)(concn. giving half-maximal transport) for lactate 12.7 ± 4.5 mM] and was inhibited by many monocarboxylates. It is concluded that a H+ gradient, not a Na+ gradient, is the driving force for active transport of lactate in rabbit intestinal brush-border membrane vesicles.
  • Published In

    Digital Object Identifier (doi)

    Author List

  • Tiruppathi C; Balkovetz DF; Ganapathy V; Miyamoto Y; Leibach FH
  • Start Page

  • 219
  • End Page

  • 223
  • Volume

  • 256
  • Issue

  • 1