Fig. 1.

Synthesis of primary bile acids from cholesterol in hepatic microsomes. The main primary bile acids, cholic acid and chenodeoxycholic acid, are synthesized in hepatocyte microsomes via classic or alternative pathways; the bile acids are then conjugated with glycine or taurine in liver peroxisomes to produce the amphipathic structure that contains both hydrophobic (lipid-soluble) and polar (hydrophilic) regions. The cholesterol portion of a bile acid is hydrophobic and the amino acid conjugate is polar and hydrophilic.