Altered expressions of cardiac Na/K-ATPase isoforms in copper deficient rats.
OBJECTIVE
The aim was to determine if copper deficiency affects the expression of Na/K-ATPase alpha isoforms in the rat heart.


METHODS
Copper deficiency was induced by placing weanling rats on a copper deficient diet for 4-5 weeks. Adult ventricular tissue, isolated ventricular myocytes, and brain stems of the control and deficient rats were compared for Cu, Zn-superoxide dismutase (CuZn-SOD) activity and for protein and mRNA contents of Na/K-ATPase alpha isoforms.


RESULTS
In brain stem, where copper deficiency did not alter CuZn-SOD activity, mRNA and protein levels of alpha isoforms also remained unchanged. In ventricular tissue and ventricular myocytes, copper deficiency reduced CuZn-SOD activity, mRNAs of alpha 1 and alpha 2 isoforms, and the alpha 2 isoform protein. The alpha 1 isoform protein of ventricular tissue and its myocytes was marginally reduced by copper deficiency.


CONCLUSIONS
In the rat ventricular tissue, oxidative stress resulting from copper deficiency (1) enhances the turnover of the more oxidant sensitive alpha 2 isoform to a greater extent than the turnover of the alpha 1 isoform; (2) regulates mRNA levels of alpha 1 and alpha 2 isoforms; and (3) contributes to the cardiomyopathy of copper deficiency.
Huang
W
W
Medical College of Ohio, Toledo 43699-0008, USA.
Lai
C C
CC
Wang
Y
Y
Askari
A
A
Klevay
L M
LM
Askari
A
A
Chiu
T H
TH
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D001921:Brain / Q000201:enzymology; D003300:Copper / Q000172:deficiency*; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000201:enzymology*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism
D007527:Isoenzymes; D012333:RNA, Messenger; D003300:Copper; D013482:Superoxide Dismutase; D000254:Sodium-Potassium-Exchanging ATPase