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Updated: Jul 16, 2026

Analysis of Nephron Composition and Function in the Adult Zebrafish Kidney
Published on: August 9, 2014
Expression of the rat renal PiT-2 phosphate transporter
J C Leung1, M Barac-Nieto, K Hering-Smith
1Department of Pediatrics, Division of Neonatalogy, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70118, USA.
Background:
NaPi-2a is the main sodium-dependent Pi (Na+-Pi) transporter in the apical membrane of the renal proximal tubule. Another group of Pi transporters, Glvr-1 (PiT-1) and Ram-1 (PiT-2), was identified. The PiT-2 cRNA induces Na+-dependent Pi uptake into Xenopus laevis oocytes. Prior studies have revealed the presence of the Pit-2 transporter in the kidney.
Objectives:
Further characterization of the PiT-2 transporter in the kidney and assessment of its developmental regulation.
Methods:
Using primers specific for the PiT-2 mRNA and an antibody specific for the PiT-2 protein, we assessed the expression and developmental regulation of the renal PiT-2 mRNA and protein.
Results:
RT-PCR analysis revealed that a 182 bp product was evident in the total kidney (TK), cortex (C), and medulla (M). Northern blots demonstrated a PiT-2 mRNA of approximately 4 kb (expected size) in the TK, C, and M. PiT-2 mRNA expression was similar in all kidney regions. RT-PCR and Northern blot analysis revealed that the PiT-2 cDNA was highly abundant in OK and MDCK culture cells. RT-PCR and Northern blot analysis revealed expected products at all ages studied. Densitometry demonstrated similar levels of expression of PiT-2 mRNA in the kidneys of older versus younger animals, and persistent expression in elderly rats. The PiT-2 protein was present in the TK, C, and M, and in OK and MDCK cells. PiT-2 protein abundance was similar at all ages studied.
Conclusions:
These studies further characterize the renal PiT-2 transporter and show that its expression is stable throughout development and ageing.
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