formation
Last reviewed 01/2018
Primary bile acids are those made in the liver. They are reliant on a steroid backbone derived from cholesterol. Cholesterol may be obtained:
- directly from the blood
- indirectly from acetate
Cholesterol is converted by the enzyme 7-alpha-hydroxylase into 7-alpha-hydroxycholesterol. The latter compound undergoes slight further modification to form the two key primary bile acids:
- chenodeoxycholic acid
- cholic acid
Secondary bile acids are formed by the action of gut bacteria on the primary bile acids. They include:
- deoxycholic acid
- lithocholic acid
Bile salts are formed from the bile acids by conjugation with taurine and glycine in the liver.