Search
bile
Biochemistry:
1) Composition:
a) bile salts
- cholic acid & chenodeoxycholic acid (major bile acid)
- in a 1st step, bile acids are converted to an acyl-CoA thioester, either in peroxisomes (primary bile acids deriving from the cholesterol pathway), or cytoplasmic at the endoplasmic reticulum (secondary bile acids)
- in a 2nd step, BAAT catalyzes conjugation of C24 bile acids (choloneates) to glycine & taurine before excretion into bile canaliculi
- conjugation increases the detergent properties of bile acids in the intestine
- bile acids are deconjugated by bacteria in the intestine & recycled back to the liver for reconjugation (secondary bile acids)
b) lecithin
c) cholesterol
d) electrolytes
- Na+: 150 mmol/L
- K+: 10 mmol/L
- Cl-: 90 mmol/L
- HCO3-: 70 mmol/L
2) metabolism
a) produced & excreted by liver
- 0.5-1.0 liters/day [1]
- 2-3 liters.day [2]
b) concentrated in the gallbladder
c) released into intestines through common bile duct in response to food entering duodenum
d) majority of bile is reabsorbed in ileum
e) returned to liver by way of enterohepatic circulation
Related
bile acid
cholesterol
duodenum
gallbladder
ileum
liver
phosphatidylcholine (lecithin)
General
extracellular compartment (extracellular space)
body fluid
References
- Cotran et al Robbins Pathologic Basis of Disease,
W.B. Saunders Co, Philadelphia, PA 1989 pg 966
- Harrison's Principles of Internal Medicine, 14th ed.
Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 477