Effect of cytokines on uptake of nontransferrin-bound iron (NTBI) into THP-1 human monocytic cells.

Cells were treated with cytokines exactly as described in the legend to Figure 1. Uptake of NTBI was then determined after 1 (■) and 4 (░) hours of incubation with ⁵⁹Fe-citrate as described in “Materials and methods.” Data are shown as means ± SD for 5 independent experiments performed in duplicate (for the 4-hour time point) and 3 independent experiments performed in duplicate (for the 1-hour time point) and are expressed as percentage of relative iron uptake as compared to the control ( = 100%). Mean iron uptake in the control was 17.5 ± 3.7 pmol/10⁶ cells per hour when investigating iron uptake over 4 hours. *P < .05 compared with the control.