QS Study

Entero-hepatie circulation of substances such as bile salts that are absorbed from the intestine and carried to the liver, where they are secreted into the bile and again enter the intestine.

About 94% of bile salts are reabsorbed into the blood from the small intestine, about one half of this by diffusion through the mucosa in the early portions of the small intestine and the remainder by an active transport process through the intestinal mucosa in the distal ileum. They then enter the portal blood and pass back to the liver. On reaching the liver, the bile salts are reabsorbed from the venous sinusoids into the hepatic cells and thus re-secreted into the bile.

In this way, about 94% of all the bile salts are re-circulated into the bile. So that on the average, these salts make the entire circuit some, 18 times before being carried out in the feces. This recirculation of bile salts is called entero-hepatie circulation of bile salts. Cycling is often related with numerous peaks and a longer apparent half-life in a plasma concentration-time profile. It is a particularly significant perception in the field of toxicology as many lipophilic xenobiotics experience this procedure causing repeated liver damage.

Fig: Entero-hepatie circulation in bile salts