Coupon Accepted Successfully!


Bile Acids

  1. Primary bile acids: Cholic and chenodeoxycholic acids are formed in the liver from cholesterol.
  2. Secondary bile acids: Deoxycholic acid and lithocholic acid are formed from primary bile acids in the intestine through the action of intestinal bacterial enzymes.
Formation Of Bile Acids
  1. Primary bile acids are synthesized in liver from cholesterol. e.g. cholic acids and chenodeoxycholic acid.
  2. 7 α-hydroxylation of cholesterol is the first committed step in the biosynthesis of bile acids and this is also a rate limiting step.
  3. 7 α-hydroxylase a microsomal enzymes requires oxygen NADPH and cytchrome P450. Vitamin C deficiency interferes with bile acids formation at the 7α-hydroxylation steps.
  4. Primary bile acids enter the bile as glycine or taurine conjugates. Since bile contains significant quantities of sodium and potassium and the pH is alkaline, so bile acid and their conjugates are in salt from—hence the term “bile salts”.
  5. A portion of the primary bile acids in the intestine is subjected to further changes by the activity of the intestinal bacteria. These include deconjugation and 7α-dehydroxylation, which produce the secondary bile acids, deoxycholic acid and lithocholic acid.
  6. The primary and secondary bile acids are absorbed almost exclusively in the ileum, returning to liver by way of portal circulation, and then secreted into the intestine. This is known as enterohepatic circulation.
  7. A small fraction of the bile salts— about 400 mg per day escapes absorption and eliminated in the feces. 

Clinical Aspects

  1. Serum cholesterol is correlated with the incidence of atherosclerosis and Coronary Heart Disease
    Of the serum lipids cholesterol is most often singled out as being chiefly concerned in the relationship. There is an inverse relationship between HDL concentration and coronary heart disease and most predictive relationship is LDL HDL cholesterol ratio (AIIMS Nov 09). This relationship is explainable in terms of proposed roles of LDL in transporting cholesterol to tissue and HDL acting as the scavenger of cholesterol in reverse cholesterol transport.
  2. Conditions characterized by increased blood cholesterol
    Hypothyroidism, Nephrotic syndrome, Diabetes mellitus, Obstructive jaundice, Type II and III hyperlipoproteinaemia.
  3. Low blood cholesterol is characteristic of hyperthyrodism. 

Test Your Skills Now!
Take a Quiz now
Reviewer Name