AJP - Renal Physiology, Vol 250, Issue 3 470-F475, Copyright © 1986 by American Physiological Society
Increased transport of inorganic phosphate in renal brush borders of spontaneously hypertensive rats
R. J. Bindels, J. A. Geertsen and C. H. Van Os
Phosphate metabolism was studied in spontaneously hypertensive rats (SHR)
and normotensive Wistar-Kyoto rats (WKY) by measuring serum phosphate
concentrations and 24-h urinary phosphate excretions in rats placed in
metabolic cages from 6 to 23 wk of age. Serum phosphate concentrations in
SHR were significantly lower than those in WKY at 6, 12, and 20 wk of age.
In addition, 24-h urinary phosphate excretion was lower in SHR relative to
WKY from 6 through 23 wk of age. The hypophosphaturia in SHR was
accompanied with an increase in the maximal transport rate of Na+-dependent
phosphate transport in renal brush border membrane vesicles (BBMV) isolated
from kidney cortex at 6, 12, and 20 wk of age. The apparent affinity for
phosphate did not differ significantly between WKY and SHR at all ages
studied. A direct relationship between maximal Na+-dependent phosphate
transport rates in BBMV and serum phosphate concentrations was observed in
both strains. In SHR, phosphate homeostasis is disturbed from 6 wk of age
on.
