AJP - Renal Physiology, Vol 247, Issue 4 543-F547, Copyright © 1984 by American Physiological Society
Uptake of Pi in basolateral vesicles after release of unilateral ureteral obstruction
S. J. Schwab, S. Klahr and M. R. Hammerman
We previously demonstrated Na+-dependent 32Pi uptake in basolateral
membrane vesicles from kidneys of normal dogs. We postulated that this
reflects Na+-dependent Pi transport across the basolateral membrane into
the proximal tubular cell in vivo that subserves cellular needs for Pi. To
ascertain whether Pi transport across the basolateral membrane was enhanced
in a condition in which delivery of Pi across the luminal membrane would be
markedly decreased, we measured Na+-dependent 32Pi uptake in basolateral
vesicles isolated from postobstructed and control kidneys of dogs following
release of unilateral ureteral obstruction. Clearance of creatinine and
filtered load of Pi were significantly decreased in postobstructed compared
with control kidneys. Na+-dependent 32Pi uptake was increased in
basolateral vesicles from postobstructed compared with control kidneys, as
reflected by increased initial rate of uptake and an increased overshoot of
32Pi transport. Our findings are consistent with an adaptation resulting in
increased transport of Pi across the basolateral membrane of the proximal
tubular cell in unilateral ureteral obstruction. This process may provide
required Pi to the cell under conditions in which decreased Pi is available
for transport across the brush border membrane.
