Effect of thyroid hormone on the expression of mRNA encoding sarcoplasmic reticulum proteins.

Publisher Website
Google Scholar
Abstract
The purpose of this study was to determine the expression of genes encoding various sarcoplasmic reticulum components that are functionally coupled with calcium release, uptake, and storage function during cardiac hypertrophy induced by thyroid hormone. Hyperthyroidism was induced in two groups of rabbits by the injection of 200 micrograms/kg L-thyroxine (T4) daily for 4 days (T4-4-day group) and 8 days (T4-8-day group). Hypothyroidism was induced in another group of rabbits by adding 0.8 mg/ml propylthiouracil to the drinking water for 4 weeks. The relative expression level of mRNA encoding different sarcoplasmic reticulum proteins was determined by RNA slot blot and Northern blot analysis. In hyperthyroid hearts, the steady-state level of cardiac ryanodine receptor mRNA and sarcoplasmic reticulum cardiac/slow-twitch Ca(2+)-ATPase mRNA were both increased to 147% (T4-4-day group) and 186% (T4-8-day group) of control, respectively, but decreased to 71% and 75%, respectively, in hypothyroid ventricles. The...