Skip to main content
. Author manuscript; available in PMC: 2018 Dec 1.
Published in final edited form as: Curr Opin Pharmacol. 2017 Nov 5;37:80–86. doi: 10.1016/j.coph.2017.09.008

Figure 1. Synthesis, secretion and enterohepatic circulation of bile acids in humans.

Figure 1

(1) Primary bile acids (BAs) are synthesized in hepatocytes from cholesterol. (2) BAs are conjugated to glycine and taurine and are stored in the gallbladder at high concentrations. (3) After feeding, conjugated BAs are secreted in the intestine where they emulsify dietary fats and form mixed micelles that facilitate digestion and absorption of the products of triglyceride digestion. (4) Conjugated BAs are actively absorbed by the apical sodium BA co-transporter (ASBT [IBAT]) at the apical membrane of enterocytes of the terminal ileum. (5) In the colon, bacteria deconjugate and dehydroxylate primary BAs to form secondary BAs, which are passively absorbed. (6) Conjugated and unconjugated BAs enter the portal vein and recirculate to the liver for re-use.

Reproduced with permission from ref. 1, Bunnett NW. Neuro-humoral signalling by bile acids and the TGR5 receptor in the gastrointestinal tract. J Physiol 2014; 592:2943–2950.