ER stress attenuates the expression of genes involved in thyroid hormone synthesis and reduces iodide uptake in FRTL-5 cells.

<p>Effect of 24-h treatment of FRTL-5 thyrocytes with different concentrations of tunicamycin (TM) on: (A) relative mRNA levels of sodium/iodide symporter (NIS), thyroglobulin (TG) and thyroid peroxidase (TPO), (B) protein level NIS, (C) Na¹²⁵I uptake in the presence and absence of the NIS-specific inhibitor KClO₄, (D) protein levels of total and p-TG, and (E) relative mRNA level of TSH receptor (TSHR). (A-E) Cells treated with DMSO used as vehicle served as control. (A, B, D, E) Bars represent relative mRNA or protein levels expressed as fold of control (0 μg/mL TM), which was set to 1.0, and are means ± SD from 3 independent experiments. (C) Bars represent counts per minute/well and are means ± SD from 3 independent experiments. (D) One representative immunoblot for total TG, p-TG and β-Actin from three independent experiments is shown. *Different from control (P < 0.05).