Chemistry

• Ketone bodies


  Water-soluble molecules or compounds that contain the ketone groups produced from fatty acids by the liver (ketogenesis)

  
• Ketone bodies


  • Acetoacetate
  • Acetone
  • β-OH butyric acid

  
• Ketonaemia

  Rise of ketone bodies in blood above normal level
• Ketonuria


  When the blood level of ketone bodies rises above the renal threshold, they are excreted in urine
• Ketosis


  Accumulation of abnormal amount of ketone bodies in tissues and body fluids
• Ketoacidosis


  Acetoacetic acid and β-OH-butyric acid are moderately strong acids, loss of buffer cations causes ketoacidosis

  
• Causes of ketoacidosis


  • Prolonged Starvation
  • Carbohydrate poor diet
  • High fat diet
  • After severe exercise
  • Uncontrolled diabetes mellitus
• Ketone Body Formation In Liver (Ketogenesis)

  1. Formation of Aceto-acetyl-CoA

  2. Formation of Acetoacetate

  3. Formation of Acetone

  4. Formation of β-OH Butyrate

  
• Ketolysis


  Utilization of ketone bodies by extrahepatic tissues as fuel

  
• Steps of ketolysis


  1. 3-Hydroxybutyrate is oxidized to acetoacetate

  2. Acetoacetate is provided with a CoA molecule from succinyl CoA

  3. Acetoacetyl CoA is converted to two acetyl CoAs

  
• Liver actively produces ketone bodies but lacks thiophorase and is unable to use ketone bodies as fuel

  
• Factors that regulate ketogenesis

  • Level of circulating F.F.As
  • Insulin/glucagon ratio
  • Hepatic acetyl CoA production
  • NAD+/NADH ratio

  
• If too many ketones build up it leads to diabetic coma.
• Ketones are formed when there is an excess of fats being broken down.