Alcohol metabolism

I. Overview

• Microbial fermentation produces 3 g/day
• Absorbed through GI tract, through lungs by inhalation
• Metabolized in liver
• zero order kinetics
• 10 ml/h

II. Metabolism

• first step: alcohol to acetaldehyde
  • Alchohol dehydrogenase
    • km = 1mm
  • Mixed function oxidase on SER
• Second step: acetaldehyde to acetate
  • aldehyde dehydrogenase
  • cytosolic enzyme
• Third step: acetate to acetyl CoA
  • acetyl CoA synthetase
  • enters TCA cycle

III. Effects of metabolism

• Produces NADH
  • skews ratio
  • inhibits gluconeogenesis
  • increases fatty acid synthesis: leads to fatty liver
• Increase VLDL and LDL plasma levels
• Affects membranes
• Ketoacidosis can occur
• B vitamin and protein deficiency
• teratogen

IV. Other metabolic effects

• Some populations affected: acetylaldehyde levels increase
  • rapid formation
  • decreased removal
• Disulfiram inactivates aldehyde dehydrogenase
  • headache
  • vasodilation
  • vomiting
  • used for chronic alcholism