Bile formation, bile acids and the enterohepatic circulation
How the liver makes bile, the synthesis and conjugation of bile acids, micelles and fat absorption, the enterohepatic circulation and its FXR-FGF19 feedback, and how the physiology explains ileal resection diarrhoea, gallstones, cholestatic pruritus, inherited transporter defects and the drugs that act on bile acids.
Tier 2Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- The liver secretes about 600 mL of bile a day. Its main solutes are bile acids, phospholipid, cholesterol and conjugated bilirubin.
- Bile acids are made from cholesterol, conjugated, secreted, used to form micelles for fat absorption, then reabsorbed in the terminal ileum and returned to the liver. About 95% is recycled.
- A pool of only 2 to 4 g cycles 6 to 10 times daily. Synthesis replaces the 0.5 g/day lost in stool and is the body's main route for removing cholesterol.
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Sources
- Sleisenger and Fordtran's Gastrointestinal and Liver Disease (11th ed.)Elsevier (Feldman, Friedman, Brandt, 2021), 2021
- Guyton and Hall Textbook of Medical Physiology (14th ed.)Elsevier (Hall and Hall, 2021), 2021
- Wahlström A, Sayin SI, Marschall HU, Bäckhed F. Intestinal crosstalk between bile acids and microbiota and its impact on host metabolism. Cell Metab 2016;24(1):41-50Cell Metabolism, 2016
- Sadowski DC et al. Canadian Association of Gastroenterology Clinical Practice Guideline on the Management of Bile Acid Diarrhea. J Can Assoc Gastroenterol 2020;3(1):e10-27Canadian Association of Gastroenterology, 2020
- Intercept announces voluntary withdrawal of Ocaliva for primary biliary cholangitis from the US marketIntercept Pharmaceuticals, 2025
- Chappell LC et al. Ursodeoxycholic acid versus placebo in women with intrahepatic cholestasis of pregnancy (PITCHES). Lancet 2019;394:849-60The Lancet, 2019
- Last updated
- 14 November 2026
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