Serum (clotted blood) or heparinised plasma
Synthesised by liver and secreted into the duodenum via the bile duct to aid lipid digestion. Following lipid digestion, the bile acids are absorbed in the ileum and return to the liver via the hepatic portal vein, where most are extracted and recycled.
An increase in plasma concentrations of bile acids usually reflects diminished hepatic function and inability to reabsorb bile acids from plasma. Bile acid concentrations may also increase following fasting, malabsorption and catabolism as the receptor proteins responsible for removing them from plasma are rapidly depleted.
See also: