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Indirect coupling of urate and p-aminohippurate transport to sodium in human brush-border membrane vesicles.
Journal article

Indirect coupling of urate and p-aminohippurate transport to sodium in human brush-border membrane vesicles.

  • Roch-Ramel F Institut de Pharmacologie et Toxicologie de l'Universite, Lausanne, Switzerland. francoise-roch-ramel@ipharm.unil.ch
  • Guisan B
  • Schild L
  • 1996-01-01
Published in:
  • The American journal of physiology. - 1996
Aged
Biological Transport
Humans
Kidney
Microvilli
Middle Aged
Pyrazinamide
Sodium
Sodium Lactate
Uric Acid
p-Aminohippuric Acid
English [14C]urate and p-[14C]aminohippurate (PAH) uptake by human brush-border membrane vesicles (BBMV) were measured in the presence of an inwardly oriented sodium gradient. No direct sodium cotransport was observed. Indirect [14C]urate coupling to sodium transport was demonstrated by cis-stimulation of [14C]urate with nicotinate or pyrazinoate (PZA) in the extravesicular medium but not by adding lactate, alpha-ketoglutarate, or beta-hydroxybutyrate. Indirect sodium coupling of [14C]PAH uptake was observed only when alpha-ketoglutarate was added to the extravesicular medium, a mechanism similar to that of basolateral membranes. The ability for PZA (and nicotinate) to cis-stimulate urate uptake was correlated with a high apparent affinity for the urate/anion exchanger. In urate-loaded vesicles, for identical medium concentrations, [14C]PZA uptake via the urateanion exchanger was 10 times higher than [14C]lactate uptake. Such high PZA affinity for the urate exchanger, working in parallel with PZA sodium cotransport can account for the stimulation of urate reabsorption by PZA in vivo.
Language
  • English
Open access status
closed
Identifiers
Persistent URL
https://sonar.ch/global/documents/138977
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