Figure 1. Effect of temperature and pH on the uptake of ¹²⁵I-hepcidin by cells expressing Fpn-GFP.

ECR293cells were either not induced (-pon) or induced with ponasterone (+pon) to express Fpn-GFP. (A) Cells were incubated with ¹²⁵I-hepcidin for 1 h at 0°C, 15°C, 23°C and 37°C, and the amount of radioactivity bound to cells was measured by gamma counting. *p<0.001, **p = 0.024 compared to uninduced cells at the same temperature. (B) Cells were incubated with ¹²⁵I-hepcidin for 1 h at pH 2, 4, 5, 6, 7, 8 and 9, and the amount of radioactivity bound to cells was measured by gamma counter. Radioactivity in uninduced cells was subtracted as background. Because of the variation in absolute counts between separate experiments, data within each experiment were normalized to ¹²⁵I-hepcidin uptake at pH 7. *p<0.01. All experiments were repeated a minimum of three times, and the error bars represent the standard deviation.