Coupled transport of p-aminohippurate by rat kidney basolateral membrane vesicles

Journal Article · Sat Oct 01 04:00:00 EDT 1988 · American Journal of Physiology; (USA)

OSTI ID:6228227

Pritchard, J B ^[1]

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1. National Institutes of Health, Research Triangle Park, NC (USA)

p-Aminohippuric acid (PAH) transport by basolateral membrane (BLM) vesicles isolated from rat renal cortex was stimulated very little by a Na{sup +} gradient (out > in). However, when micromolar concentrations of glutaric acid or {alpha}-ketoglutaric acid were added in the presence of a out > in Na{sup +} gradient, PAH uptake was accelerated >20-fold and an overshoot of greater than fivefold was produced. Other anions, e.g., fumarate, stimulated PAH uptake very modestly under these conditions, and that stimulation was totally prevented by short circuiting, i.e., with K{sup +} (in = out) and valinomycin. Glutarate-stimulated uptake was inhibited by 4-acetamide-4{prime}-({sup 14}C)-isothiocyanostilbene-2,2{prime}-disulfonic acid (SITS) and probenecid and was slightly stimulated by the imposition of an inside-negative membrane potential. Furthermore, even in the absence of a Na{sup +} gradient, glutarate-loaded vesicles exhibited a marked acceleration of ({sup 3}H)-PAH uptake (5-fold) and a modest overshoot (2.5-fold). These results suggest an indirect coupling of BLM PAH uptake to the Na{sup +} gradient by a cyclic accumulation (Na{sup +}-dependent) of glutarate followed by its efflux from the vesicle in exchange for PAH. This coupled system was absent in apical membranes. Thus net secretory transport of PAH may entail Na{sup +}-dependent, glutarate-driven PAH uptake at the BLM, followed by the exit of PAH into the lumen down its electrochemical gradient, probably in exchange for other anions, e.g., {sup 36}Cl{sup {minus}}, HCO{sub 3}{sup {minus}}, or OH{sup {minus}}.

• OSTI ID: 6228227
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 255:4; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMALS
ANIONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CHARGED PARTICLES
CHLORINE 36
CHLORINE ISOTOPES
CLEARANCE
DICARBOXYLIC ACIDS
ELECTRON CAPTURE RADIOISOTOPES
EXCRETION
GLUTARIC ACID
HIPPURIC ACID
HYDROGEN COMPOUNDS
IONS
ISOTOPES
KIDNEYS
LABELLED COMPOUNDS
LIGHT NUCLEI
MAMMALS
MEMBRANE TRANSPORT
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
RADIOISOTOPES
RATS
RODENTS
TRITIUM COMPOUNDS
VERTEBRATES
YEARS LIVING RADIOISOTOPES