The Effects of Actinomycin D, Puromycin, Cycloheximide and Hydroxyurea on 3′,5,3-Triiodo-L-thyronine Stimulated 2-Deoxy-D-glucose Uptake in Chick Embryo Heart Cellsin Vitro*†

The uptake of 2-deoxy-D-[1-3H]glucose ([1-3H]DOG) by cultured chick embryo heart cells was stimulated by L-triiodothyronine (T3). This stimulation began with the exposure to T3, rose linearly for about 8 h and reached a plateau around 24h. Actinomycin D, puromycin and cyclohexmide had no effect on the stimulated sugar uptake during the first 6h. These agents prevented the further increase in the rate of [1-3H]DOG uptake in T3-treated cultures that occurred between 6 and 24h. In the presence of hydroxyurea the uptake of [1-3H]DOG in both control and T3-treated cells was unchanged. These results suggest that some of the effects of T3 may not require new synthesis of either RNA, proteins or DNA.