Electrogenic Na+-independent Pi transport in canine renal basolateral membrane vesicles

Journal Article · Sat Mar 01 04:00:00 EST 1986 · Am. J. Physiol.; (United States)

OSTI ID:5529225

Schwab, S J; Hammerman, M R

To define the mechanism by which Pi exists from the renal proximal tubular cell across the basolateral membrane, we measured 32Pi uptake in basolateral membrane vesicles from dog kidney in the absence of Na+. Preloading of basolateral vesicles with 2 mM Pi transstimulated 32Pi uptake, which is consistent with counterflow. We used measurements of transstimulation to quantitate the transport component of 32Pi uptake. Transstimulation of 32Pi uptake was inhibited less than 30% by concentrations of probenecid as high as 50 mM. In contrast, transstimulation of 35SO4(2-) uptake by intravesicular SO4(2-) was inhibited 92% by 5 mM probenecid. Preloading basolateral vesicles with SO4(2-) did not result in transstimulation of 32Pi uptake. Accumulation of 32Pi in basolateral vesicles above steady state was driven by a membrane potential (intravesicular positive), consistent with Na+-independent Pi transport being accompanied by the net transfer of negative charge across the membrane. We conclude that carrier-mediated, electrogenic Na+-independent 32Pi transport can be demonstrated in basolateral vesicles from dog kidney. This process appears to be mediated, at least in part, via a mechanism different from that by which SO4(2-) is transported. Electrogenic Na+-independent Pi transport may reflect one means by which Pi reabsorbed across the luminal membrane exists from the proximal tubular cell down an electrochemical gradient.

• Research Organization: Washington Univ. School of Medicine, St. Louis, MO
• OSTI ID: 5529225
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States); ISSN AJPHA
• Country of Publication: United States
• Language: English

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551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALI METALS
ANIMALS
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CELL MEMBRANES
DAYS LIVING RADIOISOTOPES
DOGS
DRUGS
ELECTRIC POTENTIAL
ELEMENTS
EVEN-ODD NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
KIDNEYS
LIGHT NUCLEI
MAMMALS
MEMBRANE TRANSPORT
MEMBRANES
METALS
NUCLEI
ODD-ODD NUCLEI
ORGANS
OXYGEN COMPOUNDS
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
RADIOISOTOPES
SODIUM
SULFATES
SULFUR 35
SULFUR COMPOUNDS
SULFUR ISOTOPES
TRACER TECHNIQUES
TUBULES
UPTAKE
VALINOMYCIN
VERTEBRATES