This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Iron deficiency anemia, Subject name: Pathology
Which of the following is downregulated by Hepcidin? 
Select and explain. 
A. Ferropoin, B. Transferrin, C. DMT 1, D. Haphaestin
A: Ferropoin
Answer: A: Ferropoin 
Explanation: Regulates iron absorption. It is synthesized & released by the liver in response to increase in intrahepatic iron levels. When the body is replete with iron, Hepcidin levels increase & inhibit iron transfer from enterocyte to plasma by binding to ferropoin. It also suppresses iron release from macrophages, which is an impoant source of the iron used by erythroid precursors to make hemoglobin.