Effects of angiotensin II on NaPi-IIa co-transporter expression and activity in rat renal cortex

Liping Xu, Mehul P. Dixit, Rongji Chen, Naznin M. Dixit, James F. Collins, Fayez K. Ghishan

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


The kidney plays a major role in reabsorption of phosphate with the majority occurring in the proximal tubule (PT). The type IIa sodium-phosphate co-transporter (NaPi-IIa) is the main player in PT. The purpose of current study was to determine the effect of angiotensin II (A-II) on membrane expression of NaPi-IIa in the rat renal cortex. A-II (500 ng/kg/min) was chronically infused into the Sprague-Dawley rats by miniosmotic pump for 7 days. The arterial pressure and circulating plasma A-II level along with urine output were markedly increased in A-II rats. There was diuresis but no natriuresis. The phosphate excretion increased sevenfold on day 4 and 5.7-fold on day 7. There was no change in Na-dependent Pi uptake in brush-border membrane (BBM) vesicles between A-II-treated group and control on day 4, however, there was a 43% increase on day 7. Western blot analysis of NaPi-IIa protein abundance showed a parallel pattern: no change after 4 days of treatment and a 48% increase after 7 days of treatment. However, Northern blot analysis of cortical RNA showed no change in NaPi-IIa mRNA abundance on day 7. A-II stimulation of Na/Pi co-transport activity is a result of increases in the expression of BBM NaPi-IIa protein level and that stimulation is most likely mediated by posttranscriptional mechanisms.

Original languageEnglish (US)
Pages (from-to)114-121
Number of pages8
JournalBiochimica et Biophysica Acta - Biomembranes
Issue number2
StatePublished - Dec 15 2004


  • Brush-border membrane
  • Kidney
  • Phosphate transport
  • Phosphaturia
  • SLC34A1

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology


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