Alcohol Metabolism

Question 1

Where is does most alcohol get metabolised? Where does the remainder go?

Answer 1

> 90% of alcohol ingested is metabolised by the liver
The remainder is excreted passively in the urine and on breath

Question 2

What enzyme oxidises alcohol? What is it oxidised to?

Answer 2

Alcohol dehydrogenase oxidises alcohol to acetaldehyde

Question 3

What enzyme oxidises acetaldehyde? What is it oxidised to?

Answer 3

Aldehyde dehydrogenase oxidises acetaldehyde to acetate

Question 4

What can acetate be converted to? What metabolic pathways can this product be used in?

Answer 4

Can be converted to acetyl-CoA and used in TCA cycle or fatty acid synthesis

Question 5

What energy carrier molecule is reduced in both ethanol and acetaldehyde oxidation?

Answer 5

NAD+ is reduced to NADH

Question 6

What is the recommended limit for alcohol consumption?

Answer 6

14 units spread over at least 3 days (for both men and women)

Question 7

At what approximate rate is alcohol eliminated?

Answer 7

Roughly 7g per hour

Question 8

How can increased Acetyl-CoA affect the liver in alcohol metabolism?

Answer 8

Causes increased synthesis of fatty acids and ketone bodies -> increased synthesis of triacylglycero. This, as well as lower lipoprotein synthesis -> fatty liver

Question 9

Give another cause of fatty liver

Answer 9

Decrease in NAD+/NADH ratio -> inadequate NAD+ for fatty acid oxidation -> increased synthesis of triacylglycerol. This, along with lower lipoprotein synthesis -> fatty liver

Question 10

What drug can be used as a component of treatment for alcoholism?

Answer 10

Disulfiram - an inhibitor of aldehyde dehydrogenase. Leads to build up of acetaldehyde which causes symptoms of hangover.