The effects of increasing ferric citrate concentration on Fe uptake. Hepatocytes from Hfe KO (filled symbols) and control (open symbols) mice were incubated with 0 to 20 μM ⁵⁹Fe-citrate (ratio of 1 Fe to 100 citrate) for 2 hours at 37° C. Internalized (•, ○), membrane (▪, □), and total (▴, ▵) uptakes are shown. Results are expressed as mean ± SD (n = 3). This graph is a typical representation from 4 independent experiments performed.