Bile acids molecular regulation

Bile acids can be modified to many derivatives due to their unique molecular structures, as listed in Table 1. First, we can convert the functional groups at the side-chains from carboxylic acid to amide, alcohol, ester, and so on. Second, we can change the length of the side-chains by decreasing or increasing their methylene number. Third, we can regulate the direction of the hydroxyl groups of the skeletons at the axial or equatorial positions. 

Trottier, J., Milkiewicz, P., Kaeding, J., Verreault, M. and Barbier, O. (2006) Coordinate regulation of hepatic bile acid oxidation and conjugation by nuclear receptors. Molecular Pharmacology, 3, 212-222. 

Molecular regulation of key enzymes in the bile acid biosynthetic pathways. 432... 

The molecular regulation of cellular cholesterol metabolism has been elucidated by Brown and Goldstein [64]. Cholesterol is synthesized in the hver by the enzyme HMG-CoA reductase. Subsequently, it is transformed into bile acid in the liver and secreted to the gall bladder. The statins inhibit HMG-CoA reductase, which is a key rate-limiting enzyme in cholesterol biosynthesis. The effective removal of the bile acid from the bile pool is another viable approach to reduce plasma LDLc. Removal of bile acid from the body results in upregulation of bile acid biosynthesis, which subsequently leads to a corresponding overall drop in plasma cholesterol levels [65]. The biochemical process of cholesterol metabolism is schematically illustrated in Fig. 6. 

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