Alcohol Flashcards
Where is alcohol metabolised?
The liver
How is alcohol metabolised?
Alcohol oxidised by alcohol dehydrogenase to acetaldehyde.
Acetaldehyde oxidised by aldehyde dehydrogenase to acetate.
Acetate converted to acetyl CoA - used in TCA cycle or for fatty acid synthesis.
Recommended units per week for male and female.
14 units per week spread over at least three days for both men and women.
How fast is alcohol eliminated from the body?
Rate of about 7g per hour.
Clinical causes of acetaldehyde
Long term accumulation in the body causes liver cirrhosis and hangover symptoms.
Also oxidation of alcohol uses up NAD+.
How does acetaldehyde cause liver damage?
Excess NADH and acetyl CoA leads to changes in liver metabolism.
How is acetaldehyde toxicity normally kept to a minimum?
Aldehyde dehydrogenase has a low Km for acetaldehyde, so has a high affinity for it.
How does chronic alcohol consumption lead to lactic acidosis?
Decrease in NAD+/NADH ratio
=> inadequate NAD+ for conversion of lactate to pyruvate
=> lactate accumulates in blood
=> lactic acidosis
How does chronic alcohol consumption lead to gout?
Decrease in NAD+/NADH ratio
=> inadequate NAD+ for conversion of lactate to pyruvate
=> lactate accumulates in blood
=> kidney’s ability to excrete uric acid reduced
=> urate crystals accumulate in tissues producing gout
How does chronic alcohol consumption lead to hypoglycaemia?
Decrease in NAD+/NADH ratio
=> inadequate NAD+ for conversion of lactate to pyruvate
+ inadequate NAD+ for glycerol metabolism
=> deficit in gluconeogenesis
=> hypoglycaemia
How does chronic alcohol consumption lead to fatty liver?
Decrease in NAD+/NADH ratio
=> inadequate NAD+ for fatty acid oxidation
+ increased acetyl CoA
=> increased synthesis of fatty acids and ketone bodies
=> increased synthesis of triacylglycerol
+ lower lipoprotein synthesis
=> fatty liver
How can disulfiram be used for the treatment of alcohol dependence?
Inhibits aldehyde dehydrogenase causing accumulation of acetaldehyde causing hangover symptoms, therefore causing patients to associate drinking with nausea and hangover symptoms.
This should be part of a longer treatment plan combined with therapy.
