Deletion of Bmp6 further represses hepcidin expression in Hjv knockout mice and worsens the iron overload phenotype of females. (A) Hepcidin (Hamp), (C) Id1, and (D) Smad7 mRNA expression were measured by quantitative PCR in the liver of male (M) and female (F) littermates that had the wild-type (WT), Bmp6−/−, Hjv−/−, or double knockout (KO) genotype. (B) Serum hepcidin levels were measured by competitive ELISA on the same mice. Quantitative measurement of nonheme iron in the pancreas (E), and the heart (F) was performed according to the method recommended by Torrance and Bothwell.14 NTBI (G) was measured using the FeROS eLPI kit (Aferrix LTD). Box-and-whisker plots are shown on the graphs. Data were obtained on 10 WT, 10 Bmp6−/−, 10 Hjv−/−, and 18 double knockout males, and on 11 WT, 10 Bmp6−/−, 8 Hjv−/−, and 11 double knockout females. Means of quantitative PCR ΔCt values, log-transformed serum hepcidin, tissue iron content, and NTBI arbitrary units (AUs) in mice of the different genotypes were compared with 2-way ANOVA followed by Sidak multiple comparison tests of planned contrasts between pairs of means. *P < .05; **P < .01; ***P < .001; ****P < .0001. Hprt, hypoxanthine-guanine phosphoribosyltransferase.
