[@Chloupkova2010Stoichiometries] and accordingly shows an increased linearity for a greater range of intercellular iron concentrations (Figure \[fig:TfR2Response\]). This suggests the two transferrin receptors play different roles in sensing intercellular iron levels with TfR2 providing a wide range of sensing and TfR1 sensing smaller perturbations. The activation of TfR2 directly influences the expression of hepcidin and therefore it is desirable for it to sense large systemic imbalances. TfR1 does not modulate hepcidin expression itself instead it plays a primary role as an iron transporter .

Discussion {#discussion .unnumbered}
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Iron is an essential element of life, in humans it is involved in oxygen transport, respiration, biosynthesis, detoxification, and other processes. Iron regulation is essential because iron deficiency results in debilitating anemia, while iron excess leads to free radical generation and is involved in many diseases [@Kell2009Iron]. It is clear that healthy life depends on tight regulation of iron in the body. The mechanisms involved in iron absortion, transport, storage and regulation form a complex biochemical network [@Hower2009General]. The liver has a central role in the regulation of systemic iron metabolism through secretion of the peptide hormone hepcidin.

Here we analysed the hepatic biochemical network involved in iron sensing and regulation through 