Taurogalzouten

Taurogalzouten are a class of bile salts formed by the conjugation of bile acids with the amino acid taurine. They are found in the bile of many mammals and play a key role in the emulsification and digestion of fats. The taurine conjugation increases the water solubility of the bile acids, aiding their function in the intestinal lumen.

Biogenesis and chemical nature

In hepatocytes, bile acids are activated as CoA thioesters and then conjugated with taurine by the enzyme bile acid–CoA:amino acid N-acyltransferase (BAAT). The resulting tauro-conjugated bile acids are secreted into bile canaliculi by transporters such as the bile salt export pump (BSEP). Once in the intestine, taurogalzouten act as detergents that solubilize dietary lipids and fat-soluble vitamins, facilitating micelle formation and fat absorption.

Major species and examples

In humans, the principal taurogalzouten are taurocholic acid (tauro-cholate), taurodeoxycholic acid, and taurochenodeoxycholic acid. In many animals, particularly rodents, additional forms such as tauro-α-muricholate and tauro-β-muricholate are present. The composition of the taurogalzouten pool varies between species and can be influenced by diet and liver function.

Physiology and metabolism

Taurogalzouten are part of the enterohepatic circulation. After aiding fat digestion in the intestine, they are reabsorbed in the terminal ileum and return to the liver via the portal circulation, where they can be re-secreted into bile. This recycling helps regulate the bile acid pool and lipid digestion. Disturbances in their production or reabsorption can contribute to steatorrhea and other cholestatic conditions.