This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: AIIMS 2019, Subject name: Pathology
Hepcidin inhibits which of the following? 
Select and explain. 
A. Hepheastin, B. DMT-1, C. Cerruloplasmin, D. Ferropoin
D: Ferropoin
Answer: D: Ferropoin 
Explanation: Iron absorption is regulated by hepcidin, a small circulating peptide that is synthesized and released from the liver in response to increases in intrahepatic iron levels. Hepcidin inhibits iron transfer from the enterocyte to plasma by binding to ferropoin and causing it to be endocytosed and degraded.