Sodium-hydrogen antiporter protein in normotensive Wistar-Kyoto rats and spontaneously hypertensive rats.
OBJECTIVE
To examine the mechanism of increased Na-H antiport activity in tissues of the spontaneously hypertensive rat (SHR) by measuring the amount of sodium-hydrogen exchanger isoform 1 (NHE-1) in cultured vascular and striated muscle cells, and in ex vivo tissue extracts of membranes from the brain, heart, kidney and skeletal muscle.


METHODS
A polyclonal rabbit antibody was raised against a fusion protein consisting of a section of the carboxyl tail of NHE-1 and beta-galactosidase. Cell extracts were separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, and proteins were transferred to supported nitrocellulose. NHE-1 was detected by Western blotting and quantified by densitometry.


RESULTS
Cultured aortic and striated muscle cells from SHR contained similar amounts of NHE-1 on Western blots to those from control Wistar-Kyoto (WKY) rat cells. Ex vivo extracts of crude membranes from SHR tissues also contained quantities of NHE-1 similar to those from WKY rat tissues.


CONCLUSIONS
The increased Na-H antiport activity observed in SHR cells in vitro and in vivo is not due to an increased amount of NHE-1 protein in SHR cells. This suggests that in this model of hypertension the increased transport activity results from an increased turnover number per NHE-1 molecule.
Department of Medicine and Therapeutics, Leicester Royal Infirmary, UK.
M
M
Siczkowski
J E
JE
Davies
L L
LL
Ng
D000818:Animals; D001921:Brain / Q000378:metabolism; D002478:Cells, Cultured; D006973:Hypertension / Q000378:metabolism*; D007536:Isomerism; D007668:Kidney / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology; D009131:Muscle, Smooth, Vascular / Q000378:metabolism / Q000473:pathology; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012016:Reference Values; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*
D017923:Sodium-Hydrogen Exchangers