Anion exchange pathways for Cl sup minus transport in rabbit renal microvillus membranes
- Univ. of Iowa, Iowa City (USA) Yale School of Medicine, New Haven, CT (USA)
The authors evaluated the mechanisms of chloride transport in microvillus membrane vesicles isolated from the rabbit renal cortex. The presence of Cl-formate exchange was confirmed. Outward gradients of oxaloacetate, HCO{sub 3}, acetate, lactate, succinate, sulfate, and p-aminohippurate (PAH) stimulated the rate of Cl uptake minimally or not at all. However, an outward gradient of oxalate stimulated Cl uptake by 70%, and an outward Cl gradient induced uphill oxalate uptake, indicting Cl-oxalate exchange. Moreover, an outward formate gradient induced uphill oxalate uptake, indicating formate-oxalate exchange. Studies of inhibitor and substrate specificity indicated the probably operation of at least two separate anion exchangers in mediating Cl transport. The Cl-formate exchanger accepted Cl and formate as substrates, had little or no affinity for oxalate, was sensitive to inhibition by furosemide, and was less sensitive to inhibition by 4,4{prime}-diisothiocyanostilbene-2,2{prime}-disulfonic acid (DIDS). The Cl (formate)-oxalate exchanger also accepted Cl and formate as substrates but had high affinity for oxalate, was highly sensitive to inhibition by DIDS, and was less sensitive to inhibition by furosemide. The Cl-formate exchanger was electroneutral, whereas the Cl (formate)-oxalate exchanger was electrogenic. They conclude that at least separate anion exchangers mediating Cl transport are present on the luminal membrane of the rabbit proximal tubule cell. These exchangers may play important roles in mediating transtubular Cl and oxalate transport in this nephron segment.
- OSTI ID:
- 5030260
- Journal Information:
- American Journal of Physiology; (USA), Vol. 253:3; ISSN 0002-9513
- Country of Publication:
- United States
- Language:
- English
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CHLORIDES
UPTAKE
CHLORINE 36
KIDNEYS
PHYSIOLOGY
MEMBRANE TRANSPORT
BIOCHEMICAL REACTION KINETICS
ACID CARBONATES
ANIONS
CARBON 14 COMPOUNDS
LACTIC ACID
OXALATES
RABBITS
SUCCINIC ACID
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
CHARGED PARTICLES
CHLORINE COMPOUNDS
CHLORINE ISOTOPES
DICARBOXYLIC ACIDS
ELECTRON CAPTURE RADIOISOTOPES
HALIDES
HALOGEN COMPOUNDS
HYDROXY ACIDS
IONS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LIGHT NUCLEI
MAMMALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
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VERTEBRATES
YEARS LIVING RADIOISOTOPES
550201* - Biochemistry- Tracer Techniques