Regulation of SERCA 2 expression by thyroid hormone in cultured chick embryo cardiomycetes

The role of the thyroid hormone in the regulation of sarcoplasmic reticulum (SR) calcium-adenosinetriphosphatase (Ca-ATPase) mRNA expression in the cardiomyocyte was investigated in the midterm chick embryo heart. SR Ca2+-ATPase mRNA measurements for cardiomycetes cultured in triiodothyronine (T3) were higher than control. However, T3 had no effect on Ca2+-ATPase mRNA in the thyroid hormone receptor-negative CV-1 cells. Results suggest that T3 increases the expression of SR Ca2+ pump, but the effect is localized to heart cells.