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

Biochim Biophys Acta. 2004 Dec 15;1667(2):114-21. doi: 10.1016/j.bbamem.2004.09.005.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Angiotensin II / blood
  • Angiotensin II / metabolism*
  • Angiotensin II / pharmacology*
  • Animals
  • Blood Pressure / drug effects
  • Blotting, Western
  • Diuresis / drug effects
  • Glomerular Filtration Rate / drug effects
  • Infusion Pumps
  • Kidney Cortex / drug effects
  • Kidney Cortex / metabolism*
  • Kidney Tubules, Proximal / metabolism
  • Male
  • Microvilli / drug effects
  • Microvilli / metabolism
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Sodium-Phosphate Cotransporter Proteins
  • Sodium-Phosphate Cotransporter Proteins, Type IIa
  • Symporters / drug effects
  • Symporters / metabolism*
  • Time Factors
  • Urine / chemistry


  • RNA, Messenger
  • Slc34a1 protein, rat
  • Sodium-Phosphate Cotransporter Proteins
  • Sodium-Phosphate Cotransporter Proteins, Type IIa
  • Symporters
  • Angiotensin II