The Enzymes, Regulation, and Genetics of Bile Acid Synthesis

Annu Rev Biochem. 2003;72:137-74. doi: 10.1146/annurev.biochem.72.121801.161712. Epub 2003 Jan 16.

Abstract

The synthesis and excretion of bile acids comprise the major pathway of cholesterol catabolism in mammals. Synthesis provides a direct means of converting cholesterol, which is both hydrophobic and insoluble, into a water-soluble and readily excreted molecule, the bile acid. The biosynthetic steps that accomplish this transformation also confer detergent properties to the bile acid, which are exploited by the body to facilitate the secretion of cholesterol from the liver. This role in the elimination of cholesterol is counterbalanced by the ability of bile acids to solubilize dietary cholesterol and essential nutrients and to promote their delivery to the liver. The synthesis of a full complement of bile acids requires 17 enzymes. The expression of selected enzymes in the pathway is tightly regulated by nuclear hormone receptors and other transcription factors, which ensure a constant supply of bile acids in an ever changing metabolic environment. Inherited mutations that impair bile acid synthesis cause a spectrum of human disease; this ranges from liver failure in early childhood to progressive neuropathy in adults.

Publication types

  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Bile Acids and Salts / biosynthesis
  • Bile Acids and Salts / chemistry
  • Bile Acids and Salts / genetics*
  • Bile Acids and Salts / metabolism*
  • Cholesterol / chemistry
  • Cholesterol / metabolism
  • Enzymes / deficiency
  • Enzymes / genetics*
  • Enzymes / metabolism*
  • Homeostasis
  • Humans
  • Liver / metabolism
  • Liver Diseases / enzymology
  • Liver Diseases / genetics
  • Receptors, Cytoplasmic and Nuclear / metabolism

Substances

  • Bile Acids and Salts
  • Enzymes
  • Receptors, Cytoplasmic and Nuclear
  • Cholesterol