Lecture 1- Alcohol metabolism

Question 1

alcohol energy content

Answer 1

29 KJ/g

Question 2

where does alcohol metabolism happen

Answer 2

most >90% metabolised in the liver

Question 3

where is the rest excreted

Answer 3

passively in the urine and on the breath

Question 4

Alcohol is metabolised to

Answer 4

acetate

Question 5

outline how alcohol –> acetate

Answer 5

Alcohol is oxidised by alcohol dehydrogenase to acetaldehyde and then to acetate by aldehyde dehydrogenase

Question 6

alcohol dehydrogenase

Answer 6

converts alcohol to acetaldehyde

Question 7

acetaldehyde is

Answer 7

a toxic metabolite–> accumulation causes a hangover

Question 8

aldehyde dehydrogenase

Answer 8

converts acetaldehyde –> acetate

Question 9

acetate is then converted to

Answer 9

acetyl-CoA and used in the kreb cycle or for fatty acid synthesis

Question 10

small amount of alcohol can be oxidised by

Answer 10

P450 2E1 enzyme (CYP2E1) or by catalase in the brain

Question 11

recommended limitys

Answer 11

• 14 units/week spread over at least 3 days

Question 12

one unit of alcohol = g

Answer 12

8g

Question 13

one unit=

Answer 13

half pint of beer and small glass of wine

Question 14

rate at which alcohol is eliminated

Answer 14

at a rate of 7g per hour

Question 15

liver damaged caused by

Answer 15

acetaldehyde toxicity

Question 16

acetaldehyde toxicity to the liver usually kept to a minimum by

Answer 16

aldehyde dehydrogenase (low Km for acetaldehyde- high affinity)

Question 17

Prolonged and excessive alcohol consumption can cause

Answer 17

sufficient acetaldehyde accumulation to cause liver damage

Question 18

Excess NADH and acetyl-CoA from excessive alcohol consumption leads to changes in liver metabolism

Answer 18

• Fatty liver
• Alcoholic hepatitis
• Alcoholic cirrhosis

Question 19

Disulfiram

Answer 19

for the treatment of alcohol dependence

• Inhibitor of aldehyde dehydrogenase
• If patients drinks alcohol acetaldehyde will accumulate –> hangover symptoms

Question 21

metabolic results due to alcohol consumption

Answer 21

• lactic acidosis
• urate crystal accumulate in tissues producing gout
• hypoglycaemia
• fatty liver

Question 22

how does alcohol oxidation lead to lactic acidosis

Answer 22

1. decrease in NAD+/NADH ratio
2. inadequate NAD+ for conversion of lactate to pyruvate
3. lactate accumulates in the blood
4. lactic acidosis

Question 23

how does alcohol oxidation lead to gout

Answer 23

1. decrease in NAD+/NADH ratio
2. inadequate NAD+ for conversion of lactate to pyruvate
3. lactate accumulates in the blood
4. kidnesy ability to excrete uric acid reduced
5. urate crystals accumulate in tissues producing gout

Question 24

how does alcohol oxidation lead to hypoglycaemia

Answer 24

1. decrease in NAD+/NADH ratio
2. inadequate NAD+ for conversion of lactate to pyruvate
3. lactate accumulates in the blood
4. inadequate NAD+ for glycerol metabolism
5. deficit in gluconeogenesis
6. hypoglycaemia

Question 26

how does alcohol oxidation lead to fatty liver

Answer 26

1. increased acetyl-coA
2. increased synthesis of fatty acids and ktone bodies
3. inadequate NAD+ for fatty acid oxidation
4. increased synthesis of TAG
5. fatty liver