Question

Summarize how mammals regulate the storage and transport of iron.

Answer 1

Importance of iron:

1. Component of electron transport carriers

2. Metallic cofactor for several enzymes

3. Oxygen transport

4. Protection against pathogens

Human iron stores = 38 mg/kg for women and 50 mg/kg for men.

Most of this iron is contained in the hemoglobin. The remaining portion is found in ferritin complexes in bone marrow, spleen and liver. Liver is the primary store of physiological source of iron. 3-4 mg of iron is present in the circulating blood.

Mechanism of regulation:

1. Systemic iron levels are controlled by dietary intake by enterocytes. Systemic iron is recycled continuously.

2. Iron is continuously lost from sloughing, sweat, injuries and blood loss.

3. Animals products are the best source for iron absorption.

4. Cells uptake iron through receptor-mediated endocytosis via transferrin receptor 1 (TFR1). 5. A labile iron ion pool is maintained in the cytosol.

6. A storage iron pool is maintained as ferritin.

7. Iron export is mediated by ferroprotein.

8. Iron-responsive element-binding proteins regulate transcription and translational level of genes involved in iron metabolism.