Age- and sex-related changes of serum TE profiles and biomarkers. Concentrations of Mn (A), I (B), Cu (C), Fe (D), Se (G), and Zn (K) were analyzed in the serum of adult (24 weeks) and old (109-114 weeks) male and female C57BL/6Jrj mice (n = 4-5) receiving chow diet. Serum concentrations were determined using ICP-MS/MS (A-D, G, K). Further biomarkers were detected by ELISA (E, F) and fluorescent probes (L) to assess the Fe marker ferritin (E) and transferrin (F) as well as free Zn (L), respectively. The Se status was further validated by GPX activity (H) and relative Selenop levels (I), based on NADPH-consuming glutathione reductase coupled assay and Dot blot analysis, respectively. Statistical testing based on Two-Way ANOVA and post hoc analysis using Bonferroni’s test with * p < 0.05, *** p < 0.001 vs. adult and # p < 0.05, ## p < 0.01 vs. male.