Regulation of Na+,K(+)-ATPase alpha-subunit isoforms in rat tissues during hypertension.
We investigated the regulation of the protein expression of the alpha isozymes of Na+,K(+)-ATPase in reference to the enzyme activity in the heart, brain and skeletal muscle of rats during deoxycorticosterone acetate (DOCA)-salt hypertension. Treatment of rats with DOCA and salt for 28 days produced a significant increase in systolic blood pressure compared to the control groups which remained normotensive. Rats treated with DOCA expressed greater amounts of the immunoreactive alpha-1 isoform than untreated controls in whole heart membranes. However, the DOCA-induced increase in the alpha-1 isoform did not occur during DOCA-salt hypertension. There was a parallel change in the enzyme activity of the Na+,K(+)-ATPase and the protein expression of the alpha-1 isoform as a result of these treatments. We have also demonstrated that the hearts of DOCA-salt hypertensive rats expressed less of the alpha-2 isoform compared to the controls. We could not detect any alteration in the alpha-1 and alpha-2 isoforms of the skeletal muscle and alpha-1, alpha-2 and alpha-3 isoforms of the whole brain Na+,K(+)-ATPase during salt or DOCA treatments alone or DOCA-salt hypertension. Furthermore, the Na+,K(+)-ATPase activity was unaltered in these tissues during these treatments. In conclusion, cardiac Na+,K(+)-ATPase alpha-subunit protein expression appears to be regulated during DOCA-salt hypertension. In the skeletal muscle and brain, tissues not subjected directly to increased pressure, this regulation of the Na+,K(+)-ATPase was not apparent.
Sahin-Erdemli
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Department of Pharmacology, Louisiana State University Medical Center, New Orleans 70112, USA.
Medford
R M
RM
Songu-Mize
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D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000201:enzymology; D002384:Catalysis; D003900:Desoxycorticosterone; D004591:Electrophoresis, Polyacrylamide Gel; D006973:Hypertension / Q000139:chemically induced / Q000201:enzymology*; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D008861:Microsomes / Q000201:enzymology; D018482:Muscle, Skeletal / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D051381:Rats; D017207:Rats, Sprague-Dawley; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D007527:Isoenzymes; D003900:Desoxycorticosterone; D000254:Sodium-Potassium-Exchanging ATPase