Expression of Bmp6, Smad7, Id1, and Atoh8 in the liver of mice fed diets with different iron contents. The expression of the 4 transcripts was assessed in mice of 2 strains (B6 and D2) fed an iron-deficient (ID), iron-balanced (IB), or iron-enriched (IE) diet. Expression levels were normalized to HPRT and log2 transformed, and are expressed as means of 5 samples plus or minus standard deviation. The contribution of diet was assessed by ANOVA, and statistical significant differences relative to the iron-balanced diet were determined by Scheffe posthoc tests. *P < .05; **P < .01; ***P < .001.