Effect of triiodothyronine on chick embryo heart cells maintained in tissue culture

The effects of L-triiodothyronine (T3) on heart cells were studied in chick embryo heart cells maintained in tissue culture. T3 at a concentration of 3 x 10(-7) M had no effect on the contraction rate of these cells, either acutely or after 24 hr. On the other hand, T3 in concentrations as low as 3 x 10(-9) M stimulated both 2-deoxy-D-(1-3H) glucose uptake and lactic acid production. The effect of T3 on both deoxyglucose uptake and lactic acid production was noticed only after a lag period. Lactic acid production was measured again after removal of T3 from the media, and was found to remain elevated for at least an additional five days.