Artigos Originais July 01, 2013 July 01, 2013

Modulation of thyroid hormone receptors, TR? and TR?, by using different doses of triiodothyronine (T3) at different times

DOI: 10.1590/S0004-27302013000500006

OBJECTIVE: To examine the effect of different doses of triiodothyronine (T3) on mRNA levels of thyroid hormone receptors, TR? and TR?, at different times. MATERIALS AND METHODS: 3T3-L1 adipocytes were incubated with T3 (physiological dose: F; supraphysiological doses: SI or SII), or without T3 (control, C) for 0.5, 1, 6, or 24h. TR? and TR? mRNA was detected using real-time polymerase chain reaction. RESULTS: F increased TR? mRNA levels at 0.5h. After 1h, TR? levels increased with F and SI and TR? levels decreased with SII compared with C, F, and SI. After 6h, both genes were suppressed at all concentrations. In 24h, TR? and TR? levels were similar to those of C group. CONCLUSIONS: T3 action with F began at 1h for TR? and at 0.5h for TR?. These results suggest the importance of knowing the times and doses that activate T3 receptors in adipocytes.