Fig. 2.

ER stress decreases intracellular T₃ production. A, Equimolar production of free I⁻ and T₃ production in H4 cells, as determined by ultra performance liquid chromatography. B, D2 activity and BiP protein levels (inset) in H4 cells treated with 300 nm thapsigargin (Th) for 1 h. C, Fractional conversion of T₄ to T₃ in intact H4 cells treated with 300 nm thapsigargin for 2 h, or in panel D, cells were treated with 0.6 μm tunicamycin for 5 h. In panels B–D, all values are displayed as ±sem and are representative of three experiments, where * represents P < 0.01 vs. nontreated group by two-tailed Student's t test.