Which statement correctly describes the molecular action of hepcidin in iron homeostasis?
- A It promotes transcription of divalent metal transporter 1 on enterocytes
- B It enhances ceruloplasmin-mediated oxidation of ferrous iron prior to export
- C It binds ferroportin on enterocytes and macrophages, triggering its internalization and degradation, thereby trapping iron inside cells ✓
- D It competes with transferrin for iron binding in plasma
Correct answer: C. It binds ferroportin on enterocytes and macrophages, triggering its internalization and degradation, thereby trapping iron inside cells
Explanation
Hepcidin, produced by the liver under control of the HAMP gene and induced by interleukin-6, binds ferroportin, the sole cellular iron exporter, causing its internalization and lysosomal degradation. Iron export therefore ceases, iron accumulates in duodenal enterocytes, macrophages, and hepatocytes, and hypoferremia follows. Option A reverses the true effect, since hepcidin reduces dietary iron uptake indirectly. Ceruloplasmin and transferrin play no role in hepcidin signaling.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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