What is the rate-limiting step of bile acid synthesis?
Addition of hydroxyl group to C7 by 7-a-hydroxylase. This leads to addition of other hydroxyl groups and a terminal carboxylic acid group. 7. What is a bile salt? A: Bile acid + (glycine or taurine). These are attached similar to a peptide bond at the carboxylic acid group of the bile acid. 8. What is “enterohepatic circulation” of bile salts? A: It is the recycling of bile after secretion into the duodenum. Bile helps solubulize fats, then is reabsorbed in the terminal ileum, travels to the liver in the portal vessels, and is picked out by hepatocytes and re-secreted. About 2-3% is lost into the colon. 9. What is cholelithiasis and how does it develop? A: Cholelithiasis is the formation of gallstones that block the biliary tree and can lead to liver and pancreatic damage. It results from an imbalance of bile components i.e. too much cholesterol in the bile relative to bile salts and lecithin (phosphatidylcholine). Gallstone are mostly cholesterol. 10. How to remember what is contained
