Here, we show the following in the apical membrane of the S1 segment of the proximal tubule.
- The NaPi-IIa cotransporter, which brings 3 sodium ions with 1 HPO42-
- The NaPi-IIc cotransporter, which brings 2 sodium ions with 1 HPO42- (not in S3 segment)
- The PiT-2 cotransporter, which brings 2 sodium ions with 1 H2PO4-
The basolateral transporter of phosphate forms into the interstitial space is still unknown.
The same electrochemical gradient generated by the Na/K ATPase mentioned in the previous post serves as the force behind the sodium/phosphate cotransporter