ACVIM Small Animal Internal Medicine Practice Exam 2026 – Comprehensive Study Resource

ASBT, the apical sodium-dependent bile acid transporter, is responsible for reclaiming bile acids from the gut lumen back into enterocytes. Its highest expression is in the ileum, especially the distal ileum, making that region the primary site of active bile acid reabsorption as part of the enterohepatic circulation. Most bile acids that reach the intestine are reabsorbed there and returned to the liver via the portal circulation. The stomach does not reabsorb bile acids, the duodenum reabsorbs only a small amount, and the colon mainly handles water absorption with minimal transporter-mediated bile acid uptake. So the main location is the ileum.