Expression of iron transporter DMT1 and iron content in the duodenum. (A) Four-month-old wild-type (+/+) and homozygous TfR2 Y245X mutant (m/m) female sibling mice were treated with either PBS or iron-dextran for 3 weeks, and expression of the duodenum-specific DMT1 exon 1A transcript was measured by real-time quantitative PCR. Mice used: first group, 4-month-old wild-type and homozygous TfR2 Y245X mutant female sibling mice; second group, 6-month-old wild-type, heterozygous (+/m), and homozygous TfR2 Y245X male siblings. These mice were treated with either PBS or iron-dextran. The third group was composed of 7-month-old wild-type and homozygous TfR2 Y245X mutant mice. (C) Numbers of both DMT1 exon 1A and β-actin transcripts were quantified, and the ratio of these transcripts was calculated for each sample. Open, shaded, and closed rectangles represent wild-type, heterozygous, and homozygous TfR2 Y245X mutant mice, respectively. The mean values of each group are compared and shown in a bar graph on the right (mean ± SD, ^*P = .014, ^**P = .009). (B) Iron content in the duodenum. Mice used: first group, 6-month-old wild-type, heterozygous, and homozygous TfR2 Y245X male siblings treated with either PBS or iron-dextran; the second group: 5-month-old wild-type and homozygous TfR2 Y245X mutant mice.