Effect of angiotensin-II on renal Na+/H+ exchanger-NHE3 and NHE2.
The purpose of the present study was to determine the effect of angiotensin II (A-II) on membrane expression of Na+/H+ exchange isoforms NHE3 and NHE2 in the rat renal cortex. A-II (500 ng/kg per min) was chronically infused into the Sprague-Dawley rats by miniosmotic pump for 7 days. Arterial pressure and circulating plasma A-II level were significantly increased in A-II rats as compared to control rats. pH-dependent uptake of 22Na+ study in the presence of 50 microM HOE-694 revealed that Na+ uptake mediated by NHE3 was increased approximately 88% in the brush border membrane from renal cortex of A-II-treated rats. Western blotting showed that A-II increased NHE3 immunoreactive protein levels in the brush border membrane of the proximal tubules by 31%. Northern blotting revealed that A-II increased NHE3 mRNA abundance in the renal cortex by 42%. A-II treatment did not alter brush border NHE2 protein abundance in the renal proximal tubules. In conclusion, chronic A-II treatment increases NHE3-mediated Na+ uptake by stimulating NHE3 mRNA and protein content.
Dixit
Mehul P
MP
Department of Pediatrics and Physiology, Steele Memorial Children's Research Center, University of Arizona Health Sciences Center, 1501 N. Campbell Avenue, Tucson, AZ 85724, USA. mdixit@peds.arizona.edu
Xu
Liping
L
Xu
Hua
H
Bai
Liqun
L
Collins
James F
JF
Ghishan
Fayez K
FK
D000804:Angiotensin II / Q000378:metabolism*; D000818:Animals; D001794:Blood Pressure; D015152:Blotting, Northern; D015153:Blotting, Western; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000378:metabolism; D007672:Kidney Cortex / Q000378:metabolism; D008297:Male; D008871:Microvilli / Q000378:metabolism; D012313:RNA / Q000737:chemistry; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000737:chemistry / Q000493:pharmacokinetics; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*; D013997:Time Factors; D014867:Water / Q000737:chemistry
D012333:RNA, Messenger; C513110:Slc9a2 protein, rat; C000613387:Slc9a3 protein, rat; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers; D014867:Water; D000804:Angiotensin II; D012313:RNA; D012964:Sodium