In which type of cells does the conjugation of bilirubin take place?

In which type of cells does the conjugation of bilirubin take place?

• A. Hepatocytes
• B. Kupffer cells
• C. Macrophages
• D. Phagocytic cells

Answer: (A)

Conjugation of bilirubin happens in hepatocytes of the liver. In these cells, bilirubin is taken up and rapidly conjugated with glucuronic acid by the enzyme UDP-glucuronosyltransferase, forming bilirubin diglucuronide, which is water-soluble and ready to be excreted into bile. This step is essential to make bilirubin excretable from the body. Other cell types listed don’t perform this conjugation. Kupffer cells are liver macrophages responsible for removing old red blood cells and handling heme breakdown, not for attaching glucuronic acid to bilirubin. Macrophages and phagocytic cells in general handle debris and microbes, not the biliary conjugation process. Therefore, the site of conjugation is the hepatocytes.

Conjugation of bilirubin happens in hepatocytes of the liver. In these cells, bilirubin is taken up and rapidly conjugated with glucuronic acid by the enzyme UDP-glucuronosyltransferase, forming bilirubin diglucuronide, which is water-soluble and ready to be excreted into bile. This step is essential to make bilirubin excretable from the body.

Other cell types listed don’t perform this conjugation. Kupffer cells are liver macrophages responsible for removing old red blood cells and handling heme breakdown, not for attaching glucuronic acid to bilirubin. Macrophages and phagocytic cells in general handle debris and microbes, not the biliary conjugation process. Therefore, the site of conjugation is the hepatocytes.