Iron chelation suppresses the induction of FPN1 after erythrophagocytosis by J774 macrophages. J774 cells (approximately 1 × 10⁶) were incubated in the presence (+) or absence (-) of 15 × 10⁶ opsonized human erythrocytes (EIgG) for 1.5 hours. Noningested erythrocytes were lysed and removed, SIH was added at the indicated concentrations, and incubation was continued for 6 hours. (A) Northern analysis of FPN1. (B) Western blot analysis of FPN1. (C) FPN1 mRNA levels normalized to β-actin (♦), and protein levels of the 65-kDa FPN1 band (▪) plotted as a function of SIH concentration. A third independent experiment, in which FPN1 protein (but not mRNA) was measured, yielded similar results.