Iron

Question 1

What are; ABCG2 and FLVCR?

Answer 1

ABCG2 = ABC transporter with role in efflux of xenobiotics and haem and expressed on epithelial cells inc. SI.
FLVCR - haem efflux in haematopoietic cells.

Question 2

What is ferroportin and where is it expressed?

Answer 2

The only iron exporter in cells.

All cells, but highly in; duodenum, macrophages and placenta

Question 3

What are soluble TfRs?

Answer 3

truncated cell surface receptors. High levels in iron deficiency and low levels in overload –> possible role in iron deficiency diagnosis in inflammatory setting?

Question 4

What is intravascular haemolysis?

Answer 4

breakdown of red blood cells in circulation.
Hb bound by haptoglobin –> liver
Haem bound by haemopexin –> liver.
HAem passing through kidney reabsorbed

Question 5

Outline the distribution of iron in the body ?

Answer 5

Liver = 1g (store)
Bone marrow / erythrocytes  = 2-3g (store)
RBCs = 1800mg (Hb) 
Macrophages = 600mg (store)
Muscles = 300mg (Mb) 
Plasma Tf = 1mg

Question 6

What are the different types of haem proteins?

Answer 6

Oxygen carriers (Hb. Mb)
ETC (Cytochromes a, b, c)
Metabolism of O2 and Peroxides (cytochromes p450, NOX).

Question 7

What are the different types of iron sulphur clusters?

Answer 7

Redox enzymes (succinate dehydrogenase)
Non-redox (acotinase)

Question 8

What is another type of iron dependent protein?

Answer 8

Single Fe-containing (monoxygenases converts tyrosine to dopamine).
Dioxygenases (prolyl hydroxylase)
Fe-O-Fe enzymes (RR)

Question 9

Broadly speaking, how is iron regulated and why?

Answer 9

By adjusting intake as no mechanism to regulate its loss and body has limited capacity to extrude iron.