Where are these primary bile acids made and from what?

• A. Made by hepatocytes from cholesterol
• B. Made by intestinal bacteria from bile salts
• C. Synthesized in pancreas from amino acids
• D. Produced in spleen from fats

Answer: (A)

Primary bile acids are produced in the liver by hepatocytes from cholesterol. In humans, the main products are cholic acid and chenodeoxycholic acid, which are then conjugated with glycine or taurine to form bile salts before being secreted into bile. The process is driven by enzymes like cholesterol 7 alpha-hydroxylase, making the liver the origin of these acids. In the gut, intestinal bacteria can modify them to secondary bile acids, but the starting point—these primary acids—comes from cholesterol in the liver. The pancreas and spleen do not synthesize bile acids from amino acids or fats, respectively, so the correct statement is that these primary bile acids are made by hepatocytes from cholesterol.