Alterations of duodenal iron uptake between ACD and ACD/IDA rats in vivo. For radioactive iron uptake assays, control rats (open boxes), rats with ACD (light gray boxes), and rats with ACD with true iron deficiency (ACD/IDA; dark gray boxes) were orally fed with ⁵⁹ferric citrate using a gastric tube. At 30, 60, and 90 minutes after oral iron administration, blood was collected by tail vein puncture. Radioactive iron content in serum was measured using a γ-counter. Figure 1 contains details on graphs and statistics.