Fig. 4.

High-iron consumption perturbs copper homeostasis. Weanling C57BL/6 mice were fed 1 of 6 diets varying only in iron and copper content for 5 wk ad libitum. Hepatic copper concentrations were quantified by AAS (A). Cp (i.e., amine oxidase) activity (B) was measured in serum samples using a spectrophotometric method. Data are presented as box plots representing 4 mice per group. Two-way ANOVA on rank analysis revealed an iron main effect for liver copper concentrations (P = 0.0027). A copper main effect was also noted in regard to liver copper content and serum Cp activity (P < 0.0001 for both). Two-way Fe × Cu interactions were also noted for both measured parameters (as indicated in A and B). Since significant 2-way interactions were noted, Tukey’s multiple comparisons post hoc test was utilized to determine differences among individual groups for each parameter; labeled means without a common letter differ (P < 0.05). Furthermore, the correlation between Cp activity and liver copper concentrations was assessed using Pearson product-moment correlation analysis (C). The line of best fit is shown along with the correlation coefficient (r) (P < 0.0001).