Alcohol metabolism

Properties of ethanol

• C2H5OH

• Lipid and water soluble

• Insoluble in fats and oils

• Transported by simple diffusion

What does the equilibrium conc of alcohol in a tissue depend on and why do women have a small volume of distribution usually?

• relative water content

• Rate of blood flow

• Mass of tissue

Women have a higher body fat percentage → less water content → higher alcohol conc

When are peak alcohol levels?

• Ethanol at a single dose rather than small does

• No good in stomach → food retards gastric emptying → reduce absorption of alcohol

How is ethanol metabolised and where ?

In the liver (reminder exerted passively in the urine and on the breath)

alcohol dehydrogenase (ADH) + cytochrome P450 → form acetylaldehyde (toxic)

acetyaldehyde dehydrogenase (ALDH) converts it to acetate (not toxic) → converted to acetyl CoA in skeletal muscle by acetyl CoA synthase

Where is cytochrome P450 found and what type of it has the most effect on ethanol?

found and oxidised alcohol in the ER

CYP2E1 (isoenzyme) which high affinity to ethanol. Affinity increases with higher conc of ethanol

** CUP2E1 is Inducible

What are some common liver damages any why are they caused?

Fatty liver: Inhibition of F.A Oxidation and stimulation of triglyceride synthesis

Alcohol induced hepatitis: Generation of a free radicals from acetaldehyde

Alcohol cirrhosis: damage to hepatocytes characterised by fibrosis, abnormal flow, loss of liver function

Treatment for alcohol dependency

Disulfram

Blocks acetylaldehyde dehydrogenase → accumulation of acetaldehyde → hangover symptoms (vomiting, nausea, head ache) with small amount of alcohol