AJP - Renal Physiology, Vol 251, Issue 3 385-F398, Copyright © 1986 by American Physiological Society
Phosphate transport across renal proximal tubular cell membranes
M. R. Hammerman
The transport of phosphate across the plasma membrane of the renal proximal
tubular epithelial cell is thought to take place through the activities of
specific transporters located in the membrane. The activities of these
transporters are essential to effect the reabsorption of phosphate present
in glomerular ultrafiltrate. In addition, their activities are thought to
be important for the maintenance of metabolic functions in the proximal
tubular cell. Studies utilizing proximal tubular brush-border and
basolateral membranes isolated from mammalian kidney have provided
significant insights into the mechanisms by which phosphate transport
across the brush-border and basolateral membranes of the intact proximal
tubular cell occurs and is modulated. In this editorial review, the results
of many of these studies are summarized. Particular emphasis is placed on
studies that utilized isolated membranes to determine the mechanism by
which the phosphaturic action of parathyroid hormone is mediated in the
renal proximal tubule. On the basis of studies conducted in isolated
membranes and in more physiologically intact preparations, models are
constructed to integrate the role of the brush-border and basolateral
membranes in the transport of phosphate into and out of the renal proximal
tubular cell.
