Dissociation of the Intrinsic Factor-Vitamin B₁₂ Complex by Bile: Contributing Factor to B₁₂ Malabsorption in Pancreatic Insufficiency

Abstract

Human bile incubated with vitamin B₁₂ bound to intrinsic factor in human gastric juice will effectively dissociate this complex, and the vitamin will transfer to non-intrinsic factor unsaturated binding protein(s) contained in bile. Preincubation of the bile with pancreatic enzymes, particularly trypsin, and pepsin, decreases this effect of bile on the intrinsic factor-vitamin B₁₂ complex by digesting the unsaturated binder(s) in the bile. These studies help explain why there is malabsorption of tracer amounts of vitamin B₁₂ in some patients with pancreatic insufficiency, and why this abnormality is correctable by the administration of pancreatic extract.

Key-words:

• Absorption
• bile
• digestion
• intrinsic factor
• pancreas
• vitamin B₁₂