The pluripotential P19 teratocarcinoma cell line was shown to differentiate into cardiac myocytes, as demonstrated by electron microscopic study and by the identification of specific markers, as the result of treatment with 3,3,5-triiodothyronine. This differentiation was dose dependent. The induction of cardiac differentiation was accompanied by an enrichment of nuclear receptors capable of recognizing RGG (T/A) CA direct repeats spaced by 4 base pairs in their promoter regions play an important role in the cardiac differentiation induced by T3 in P19 teratocarcinoma cells.
