Regulating iron absorption dependent on apical import and basolateral export. At the duodenal enterocyte, where iron is absorbed, hepcidin functions as a negative regulator at the basolateral surface, where ferroportin exports iron from duodenal enterocytes into the circulation. Hepcidin-mediated changes in enterocyte iron content modulate HIF2α in enterocytes. HIF2α is stabilized when hepcidin is low during iron deficiency, resulting in increased transcription of DMT1 and Dcytb as well as ferroportin messenger RNA Together, stabilization of HIF2α in the gastrointestinal tract with suppression of hepcidin would provide the most potent stimulus for iron absorption. In high-hepcidin states, ferroportin internalization and degradation result in the accumulation of iron within the enterocyte, and it is excreted in the stool with the normal frequent turnover of the intestinal mucosa. Dcytb, duodenal cytochrome B; DMT1, divalent metal transporter 1; Fe, iron; FPN1, ferroportin 1; Tf, transferrin.