Alcohol Metabolism

Question 1

How is most alcohol metabolised?

Answer 1

Oxidised by alcohol dehydrogenase to acetaldehyde

Acetaldehyde oxidised by aldehyde dehydrogenase to acetate

Acetate converted to acetylCoA

Mainly metabolised in liver

Question 2

What is the effect of alcohol oxidation in the liver?

Answer 2

NAD+ levels inadequate for fatty acid oxidation, conversion of lactate to pyruvate and metabolism of glycerol

Decreased use of lactate results in lactic acidosis

Question 3

What is the effect of the inability to metabolise glycerol?

Answer 3

Gluconeogenesis cannot be activated

Question 4

What is the effect of increased availability of acetylCoA?

Answer 4

If it cannot be oxidised due to low NAD+/NADH ratio- increased synthesis of fatty acids and ketone bodies

Question 5

What is the effect of increased synthesis of fatty acids in the liver?

Answer 5

Increased synthesis of triaglycerols

Triaglycerols cannot be transported from the liver cells due to lack of lipoprotein synthesis- fatty liver

Question 6

What is a possible effect of increased synthesis of ketone bodies in the liver?

Answer 6

Keto-acidosis

Question 7

What is an indicator of liver cell damage?

Answer 7

Transaminases and gamma glutamyl transpeptidases in the blood

Question 8

Why does damaged liver cause jaundice?

Answer 8

Damaged liver cells have reduced capacity to take up and conjugate bilirubin- causing hyperbilirubinaemia

Question 9

Why may a damaged liver cause hyperammonaemia and increased levels of glutamine?

Answer 9

Reduction in capacity of liver cells to make urea

Question 10

What are the effects of reduced protein synthesis in liver cells?

Answer 10

Decreased synthesis of albumin- oedema

Decreased synthesis of clotting factors- increased blood clotting time

Decreased synthesis of lipoproteins- inability to transport lipids away from the liver- fatty liver