Decreased Na,K-ATPase gene expression in cardiomyopathic hamster hearts.
We studied Na,K-ATPase mRNA expression in cardiomyopathic (Bio 14.6) and normal (F1b) Syrian hamster ventricles. In Northern blot analysis, Na,K-ATPase alpha 1, alpha 2, alpha 3 and beta 1 isoform mRNAs were detected in 3-week-old Bio 14.6 and F1b hamster ventricles. We then investigated the expression of alpha 1 subunit mRNA in Bio 14.6 hamster ventricles at the ages of 3 weeks prehypertrophic and 30 weeks hypertrophic, and in age-matched F1b hamster ventricles. The alpha 1 subunit mRNA levels in Bio 14.6 hamster ventricles were approximately 50% lower than those in F1b hamster ventricles at both 3 and 30 weeks of age. Na,K-ATPase activity measured in membrane fractions from the ventricles of 3-week-old Bio 14.6 hamsters was also approximately 20% lower than that of F1b hamsters, suggesting that the differences in the mRNA level were associated with the differences in the protein level. We conclude that Na,K-ATPase mRNA expression and enzyme activity are significantly decreased in the hearts of Bio 14.6 hamsters even before the onset of hypertrophy and cardiomyopathy, suggesting that the altered expression of Na,K-ATPase gene is an early event in the pathogenesis of cardiomyopathy in this animal model.
Tsuruya
Y
Y
Department of Cardiology, Jichi Medical School, Tochigi, Japan.
Ikeda
U
U
Yamamoto
K
K
Seino
Y
Y
Kanbe
T
T
Shimada
K
K
D000818:Animals; D015152:Blotting, Northern; D009202:Cardiomyopathies / Q000201:enzymology*; D002312:Cardiomyopathy, Hypertrophic / Q000201:enzymology; D006224:Cricetinae; D015971:Gene Expression Regulation, Enzymologic; D008297:Male; D008647:Mesocricetus; D009206:Myocardium / Q000201:enzymology*; D012333:RNA, Messenger / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics*
D012333:RNA, Messenger; D000254:Sodium-Potassium-Exchanging ATPase