Sulfate-bicarbonate exchange in brush-border membranes from rat renal cortex

Journal Article · Sun Feb 01 00:00:00 EST 1987 · Am. J. Physiol.; (United States)

OSTI ID:5298985

Pritchard, J B

Under Na/sup +/-free conditions /sup 35/SO/sub 4//sup 2 -/ uptake by rat renal brush-border membrane (BBM) vesicles could be driven by imposition of a HCO/sup -//sub 3/ gradient (in greater than out). The initial rate of /sup 35/SO/sub 4//sup 2 -/ uptake was stimulated 10-fold, and peak overshoot exceeded equilibrium uptake by 2-3 times. Cl/sup -/, SCN/sup -/, NO/sub 3//sup -/, I/sup -/, and OH/sup -/ were able to substitute for HCO/sub 3//sup -/. Divalent anions, including /sup 35/SO/sub 4//sup 2 -/ itself, were less effective as counterions. HCO/sub 3//sup -/-SO/sub 4//sup 2 -/ exchange was cis-inhibited by disulfonic stilbenes, ((SITS)(DIDS)), phloretin, Hg, and S/sub 2/O/sub 3//sup 2 -/. HCO/sub 3//sup -/-driven /sup 35/SO/sub 4//sup 2 -/ uptake was saturable, with an apparent K/sub m/ of 0.4 mM for SO/sub 4//sup 2 -/. Simultaneous imposition of Na/sup +/ and HCO/sub 3//sup -/ gradients produced approximately additive stimulation of /sup 35/SO/sub 4//sup 2 -/ uptake. The HCO/sub 3//sup -/-driven component of /sup 35/SO/sub 4//sup 2 -/ uptake, but not the component driven by Na/sup +/, was inhibited by SITS. Finally, Na/sup +/-driven SO/sub 4//sup 2 -/ accumulation could be reduced by imposing an out greater than in HCO/sub 3//sup +/ gradient, conditions accelerating exchange driven SO/sub 4//sup 2 -/ efflux. These findings indicate the presence of separate Na/sup +/-SO/sub 4//sup 2 -/ cotransport and SO /sub 4//sup 2 -/-anion exchange pathways in the same BBM vesicles.

• Research Organization: National Institutes of Health, Research Triangle Park, NC
• OSTI ID: 5298985
• Journal Information: Am. J. Physiol.; (United States), Vol. 252:2
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ACID CARBONATES
MEMBRANE TRANSPORT
SULFATES
SULFUR 35
ALKALINE PHOSPHATASE
CATIONS
CELL MEMBRANES
KIDNEYS
PHYSIOLOGY
RATS
SODIUM SULFATES
TIME DEPENDENCE
ALKALI METAL COMPOUNDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CHARGED PARTICLES
DAYS LIVING RADIOISOTOPES
ENZYMES
ESTERASES
EVEN-ODD NUCLEI
HYDROLASES
IONS
ISOTOPES
LIGHT NUCLEI
MAMMALS
MEMBRANES
NUCLEI
ORGANS
OXYGEN COMPOUNDS
PHOSPHATASES
RADIOISOTOPES
RODENTS
SODIUM COMPOUNDS
SULFUR COMPOUNDS
SULFUR ISOTOPES
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques