The effect of inflammation on hepcidin mRNA and serum iron in WT and IL-6 KO mice. WT (circles) and IL-6 KO (triangles) mice on an iron-depleted diet were treated with a single subcutaneous injection of turpentine. (A) Median expression of hepcidin-1 (normalized to mouse β-actin) increased 12-fold in WT mice treated with turpentine (n = 13) compared with PBS-treated controls (n = 10, P < 0.001 by Mann-Whitney rank sum test). Conversely, expression fell 6.4-fold in turpentine-treated IL-6 KO mice (n = 13) compared with controls (n = 11, P = 0.014). P < 0.001 for the comparison of WT to IL-6 KO mice (by two-way ANOVA). (B) Mean serum iron fell 49% in WT mice treated with turpentine (n = 9) compared with controls (n = 7, P = 0.015 by Student's t test), whereas there was a slight and marginally significant increase in median serum iron of IL-6 KO mice (n = 9 and n = 7, respectively; P = 0.049). The difference between iron decrease in WT and IL-6 KO mice was highly significant (P < 0.001 by two-way ANOVA).