Flashcards in Alcohol Metabolism Deck (26):
How is alcohol removed from the body?
90% metabolised by the liver, Remainder excreted passively in urine and on breath
What is the main process of alcohol metabolism?
- Alcohol oxidised by alcohol dehydrogenase to acetaldehyde, converting NAD + to NADH
- Acetaldehyde oxidised to acetate by aldehyde dehydrogenase, converting NAD + to NADH
- Acetate converted into acetyl~CoA
What happens to the acetyl~CoA produced in alcohol metabolism?
Used in TCA cycle or for fatty acid synthesis
How can smaller amounts of alcohol be metabolised?
- Oxidised by cytochrome P450 2E1 enzyme (CYP2E1)
- By catalase in the brain
What are the recommended maximum units of alcohol?
- 21 units per week for men
- 14 units per week for women
How much is 1 unit of alcohol?
At what rate is alcohol metabolised?
Eliminated at a rate of ~7g
What relationship does alcohol metabolism show?
0 order kinetics- linear elimination
What causes a hangover?
Accumulation of the toxic metabolite acetaldehyde
How is acetaldehyde toxicity normally kept to a minimum?
By aldehyde dehydrogenase
Does aldehyde dehydrogenase have a high or low Km for acetaldehyde?
What does excess acetaldehyde cause?
What can cause sufficient acetaldehyde accumulation to cause liver damage?
Prolonged and excessive alcohol consumption
What effect can excess NADH and acetyl~CoA have on the liver?
Can lead to changes in liver metabolism
What conditions can be caused by liver damage?
- ‘Fatty liver’
- Alcoholic hepatitis
- Alcoholic cirrhosis
What is fatty liver caused by?
Why does increased synthesis of triacylglycerol occur in due to excessive alcohol consumption?
Because there is increased synthesis of fatty acids and ketone bodies because of increased acetyl~CoA (as is the end product of alcohol metabolism), and inadequate NAD + for fatty acid oxidation as decrease in NAD + /NADH ratio
What has happened in lactic acidosis?
Lactate has accumulated in the blood
Why does lactate accumulate in the blood in chronic alcohol consumption?
Because inadequate NAD + for conversion of lactate to pyruvate
What is gout?
When urate crystals accumulate in tissues
Why does chronic alcohol consumption cause gout?
Because of the kidneys inability to excrete uric acid is reduced because of inadequate NAD + conversion of lactate to pyruvate (uric acid and lactate share a common excretion pathway)
How does chronic alcohol consumption cause hypoglycaemia?
Gluconeogenesis deficit, because inadequate NAD + for conversion of lactate to pyruvate and for glycerol metabolism
What can be used to treat alcohol dependance?
What does disulfiram do?
Inhibits aldehyde dehydrogenase
What happens if a patient on disulfiram drinks alcohol?
Acetaldehyde will accumulate, causing symptoms of hangover