Figure 3. Effects of cycloheximide on the induction of IL-6 by TSH.

Evidence that TSH delays IL-6 mRNA degradation. (A) Orbital fibroblasts and fibrocytes were treated with nothing or bTSH (5 mIU/mL) in the absence or presence of cycloheximide (10 µg/mL) for 6 h. Cellular RNA was isolated, and RT-PCR performed for IL-6. Ct values were normalized to GAPDH. Data are expressed as mean ± SD of three independent determinations. In 3 separate experiments, IL-6 production increased 31.8±2.8-fold in fibroblasts. (B) (left panel) Orbital fibroblasts and (right panel) fibrocytes were pretreated with bTSH (mIU/ml) for 12 h. Some culture wells were shifted to medium without TSH while the others were continued in its presence. All cultures received DRB (50 µM) at time “0” and were harvested at the times indicated along the abscissas. RT-PCR was performed and data graphed as a best fit line. Data are expressed as percent of transcript levels at time “0” ± SD of triplicate independent determinations, each from a separate experiment. (*, P<0.05 TSH-treated vs untreated cultures).