For DVM scholars

2. • Most essential trace element
• Total body iron - 3 to 5 g
• 75% in blood, liver, bone marrow & muscles.
• Present in almost all cells.
• Iron containing compounds include:-
 Heme iron containing molecules
Hemoglobin, myoglobin, cytochrome b, c &
cytochrome oxidase, catalase, peroxidase.
 Non-heme iron containing molecules
SDH, xathine oxidase, Transferrin, ferritin,
hemosiderin, iron sulfur proteins

3. Why our body need Iron ?

4. Sources
 Rich sources - liver, eggs, fruits & yeast
 Moderate – meat, fish, green leafy vegetables & cereals.
 Jaggery - good source of iron
 Milk - poor source of iron.

5. Biochemical functions
 Component of several functionally important molecules.
 Synthesis of hemoglobin, myoglobin, cytochromes, catalase
And peroxidase.
 Cytochromes & certain non-heme proteins are necessary
for ETC & oxidative phosphorylation.
 Peroxidase, the lysosomal enzyme is required for
phagocytosis & killing of bacteria.

6. Metabolism of iron
Absorption
 Iron is absorbed from upper small intestine.
 Iron is absorbed in three forms:
(1) ferrous iron (2) ferric iron (3) heme iron.
 Absorbed mainly in the ferrous form.
 Ferric ions are reduced with ascorbic acid & glutathione to
more soluble ferrous (Fe2+) form which is more readily
absorbed than Fe3+
 After taken up by the intestinal mucosa, iron is either
stored in the form of ferritin in the mucosal cells or
transported across the mucosal cells to the plasma in the
form of transferrin.

7. 

8. REGULATION OF ABSORPTION
 Mucosal Regulation
 Stores Regulation
 Erythropoietic regulation

10. Important Proteins
 Haemoglobin
 Divalent metal transporter 1
 Ferroportin (SLC40A1)
 Hepcidin
 Growth differentiation factor and twisted
 gastrulation protein Ferroportin (SLC40A1)
 Matriptase - 2 (TMPRSS6)
 Transferrin and transferrin receptors
 Ferritin and haemosidern

11. IRON TRANSPORT
 Transport form of iron is transferrin, a beta globulin.
 Normal plasma level – 250mg/100ml. Increased in iron deficiency
 Total Iron Binding Capacity in plasma is 400mg/100ml, by transferrin.
 1/3 of this capacity is saturated with iron, serum iron is about 120mg/dL
 Ceruloplasmin is the ferroxidase which oxidises ferrous to ferric state.
 Transferrin receptors are present on most cells, especially which
synthesize heme.
 Iron transferrin complex taken up by body cells by receptor mechanism.
 The receptor binds 2 molecules of transferrin and is internalized.
 Iron is taken up by the cells and the receptor molecules are externalized.
 Reticulocyte can internalize 1 million atoms of iron/minute.

14. STORAGE OF IRON
 The storage form of iron is ferritin.
 Its seen in intestinal mucosal cells, liver,
spleen and bone marrow.
 Apoferritin can take up to 4000 atoms of
iron per
molecule.

15. EXCRETION
 Iron is a one way element
 Regulation of homeostasis is done at level of absorption.
 Almost no iron is excreted through urine. Feces contains
unabsorbed iron as well iron trapped in intestinal cells that
are desquamated.
 30% of intestinal lining cells are replaced every day hence
this loss is considerable.
 All cells in skin contain iron. Hence iron is lost by
shedding of upper layers of skin.