What is the process called by which microbiota convert primary bile acids to secondary bile acids?

What is the process called by which microbiota convert primary bile acids to secondary bile acids?

• A. Deconjugation
• B. 7β-hydroxylation
• C. 7α-dehydroxylation
• D. Sulfation

Answer: (C)

Microbiota modify bile acids by removing the 7α-hydroxyl group, a process called 7α-dehydroxylation. Primary bile acids made in the liver—cholic acid and chenodeoxycholic acid—are secreted (often after conjugation with glycine or taurine) into the intestine. Certain gut bacteria carry out 7α-dehydroxylation, producing the secondary bile acids deoxycholic acid from cholic acid and lithocholic acid from chenodeoxycholic acid. This step is distinct from deconjugation, which simply removes the glycine or taurine conjugate; it is also different from 7β-hydroxylation and from sulfation, which are not the pathways that generate these secondary bile acids.

Microbiota modify bile acids by removing the 7α-hydroxyl group, a process called 7α-dehydroxylation. Primary bile acids made in the liver—cholic acid and chenodeoxycholic acid—are secreted (often after conjugation with glycine or taurine) into the intestine. Certain gut bacteria carry out 7α-dehydroxylation, producing the secondary bile acids deoxycholic acid from cholic acid and lithocholic acid from chenodeoxycholic acid. This step is distinct from deconjugation, which simply removes the glycine or taurine conjugate; it is also different from 7β-hydroxylation and from sulfation, which are not the pathways that generate these secondary bile acids.