Thyroid hormone induction of rat myocardial Na+-K+-ATPase : α1-, α2-, and β1-mRNA and -protein levels at steady state

In this study, we measured the time courses of change in Na + -K + -ATPase α 1 -, α 2 -, and β 1 -subunit mRNA and protein abundance in cardiac myocytes isolated from euthyroid, hypothyroid, and hyperthyroid (hypothyroids injected daily with 1 μg T 3 /g body wt) rats. In hypothyroids,α 1 -, α 2 -, and β 1 ,-protein levels were decreased to 0.55, 0.42 and 0.57 of euthyroids, predicting the decrease in Na + -K + -ATPase activity to 0.53 of control