enterohepatic circulation (bile salts)
Last reviewed 01/2018
The liver secretes primary and secondary bile salts into the duodenum. Along the proximal and distal ileum, primary bile salts are reabsorbed into the portal circulation. After formation by deconjugation, the secondary bile acids are reabsorbed predominantly in the colon.
From portal circulation, bile salts or acids are reabsorbed into the liver from the blood by an active transport mechanism. The bile acids are conjugated before resecretion.
The total bile salt pool in a healthy adult is around 5grams; this may be recycled up to 10 times per day with loss of only 3-8% into the faeces. To balance the loss, the liver produces 0.1-0.5mg per day of primary bile salts.