Control of proximal tubular apical Na/P-i cotransport

Two renal proximal tubular apical sodium-dependent transport systems for phosphate (Na/P-i cotransporter) have been identified, Recent studies demonstrated that the abundance of the type II Na/P-i cotransporter in the brush border is critical for the capacity of phosphate reabsorption. Evidence was obtained that a change of apical Na/P-i cotransporters may occur via endo/exocytic processes and via protein-synthesis-dependent mechanisms involving altered transcription and/or stability of mRNA. In addition, acute control of apical Na/P-i cotransport may occur via the pH dependence and electrogenicity of the Na/P-i cotransporter.