Effects of IL-1β on iron homeostasis in mice. IL-1β was injected intraperitoneally at a dose of 250 ng/mouse. Groups of animals (n = 3/time point) were sacrificed at the indicated times after injection, and various parameters were analyzed. A, liver hepcidin expression. *, p = 0.02; **, p = 0.0002. Con, control. B, serum iron concentrations. *, p = 0.02. C, immunoblot of liver lysates with antibodies to phosphorylated SMAD1/5/8 (pSMAD1/5/8) or total SMAD1. D, quantitation of Western blots corresponding to C. The intensities of the phosphorylated SMAD1/5/8 and total SMAD1 bands in blots from multiple experiments were determined by Li-Cor imaging, and the ratio was calculated. *, p = 0.008; n = 3 samples/group (except for the 6-h time point, where n = 2) from multiple experiments.