Figure 1. Changes elicited by IL-6 in HEK-293 cells transiently expressing D2.
IL-6 concentrations, as observed in critically ill patients, inhibited D2 deiodination by intact cells (A) in a dose-dependent fashion (B), an effect already observed after 2 hours of incubation (C). The effects of IL-6 on intact cell T3 production were unaffected by low FT4 (D) or elevated rT3 levels (E). In contrast, similar doses of IL-6 enhanced D2 activity on DTT-stimulated assay in sonicated cells (F). Data are mean ± SD of at least 3 independent experiments. The net iodide release in this system is specific and equivalent to T3 production (5). *P < 0.001 versus control.