Iron Homeostasis

Question 1

How much iron exists in the body and what proportion of this exists in red blood cells?

Answer 1

4g in total, 3g exists in RBCs

Question 2

Other than red blood cells, where does iron exist in the body?

Answer 2

Myoglobin
Cytochromes
Peroxidases
Xanthine oxidase
Catalases
RNA reductase

Question 3

Which molecule is the main storage system for iron?

Answer 3

Ferritin

Question 4

Other than in ferritin, how can iron be stored?

Answer 4

Haemosiderin

Question 5

Serum ferritin may be elevated in response to tissue inflammation. Why is this?

Answer 5

Because it is an acute phase protein

Question 6

What is the name of the glycoprotein, synthesised by hepatocytes which transports iron in the plasma?

Answer 6

Transferrin

Question 7

Normally, how saturated is transferrin with iron?

Answer 7

30%

Question 8

In what cells are the majority of the receptors for transferrin located?

Answer 8

Red blood cell precursors and hepatocytes

Question 9

How much iron needs to be consumed each day in the diet to replace lost iron?

Answer 9

1-2mg

Question 10

Nutritional iron deficiency is common in the UK. T/F?

Answer 10

False

Question 11

In what foods would you find hadm and non haem iron?

Answer 11

Red meat - haem iron

White meat, green veg, cereals -non haem iron

Question 12

Where does iron absorption predominantly take place?

Answer 12

Duodenum

Question 13

Non haem iron must be reduced to the ferrous form for absorption to take place. Which enzyme does this?

Answer 13

Cytochrome b1

Question 14

Which vitamin influences iron absorption?

Answer 14

Vitamin c

Question 15

What is the name of the transporter which transports iron into the enterocyte during absorption?

Answer 15

Divalent metal transporter one

Question 16

What protein transports iron across the basolateral membrane of the enterocyte?

Answer 16

Ferroportin

Question 17

What is the role of hepcidin in iron absorption?

Answer 17

Hepcidin binds to and degrades ferroportin and thus reduces GI iron absorption and reduces macrophage iron release

Question 18

What gene is required for the synthesis of hepcidin in the liver?

Answer 18

HFE gene

Question 19

As a general rule, for which group of patients should it always be assumed that iron deficient anaemia is related to GI blood loss until proven otherwise?

Answer 19

Men and postmenopausal women

Question 20

Which vitamins and minerals can be deficient as a result of coeliac disease?

Answer 20

Folate
Iron
vitamin b12

Question 21

What is the cause of hereditary haemochromatosis?

Answer 21

It is an autosomal recessive condition where there are abnormalities of the HFE gene which means that functional hepcidin is not produce and iron levels are too high

Question 22

How saturated is transferrin with iron in hereditary haemochromatosis?

Answer 22

100%

Question 23

What are the consequences when excess iron accumulates in various tissues due to hereditary haemochromatosis?

Answer 23

Cirrhosis of the liver
Pancreas damage resulting in diabetes
Skin bronzing
Arthritis
Restrictive cardiomyopathy

Question 24

How is hereditary haemochromatosis treated in non anaemic patients?

Answer 24

Venesection