Figure 3.

Twenty-eight-month-old mice have lower serum iron concentration and lower transferrin saturation than 6-month-old mice. Testosterone supplementation increased serum iron and transferrin saturation in the old mice without a significant effect on the young mice but decreased serum ferritin similarly in both young and old animals. Baseline serum erythropoietin (EPO) was higher, and hepatic hepcidin messenger RNA (mRNA) expression level was lower in the old mice than that in the young mice. Testosterone did not affect serum EPO levels at either age but reduced hepatic hepcidin mRNA expression levels in the young mice. Results are shown as mean ± standard error of mean, N = 9 for each group. Data were analyzed by one-way analysis of variance, followed by Tukey’s test. Y, young adult; C, vehicle; T, testosterone; O, older mice.