Thyroid hormones: effect of physiological concentrations on cultured cardiac cells.

Cultured cardiac cells prepared from newborn rat heart will respond in vitro to physiological concentrations of L-triiodothyronine. The cells are grown in a culture medium that contains hypothyroid calf serum. A dose response relationship of L-triiodothyronine indicates that this system may be a useful model for elucidation of the mechanism of thyroid hormone effects on the heart.