Pancreatic Extract and the Intestinal Uptake of Vitamin B₁₂

Abstract

To determine the mechanism by which pancreatic extract (PE) corrects the malabsorption of vitamin B₁₂ in chronic pancreatic insufficiency (CPI), the following hypotheses were investigated: Firstly, PE might stimulate the absorption of vitamin B₁₂ by changing the intestinal pH, secondly PE might stimulate the intestinal uptake of unbound vitamin B₁₂, thirdly PE might abolish the inhibitory effect of vitamin B₁₂ binders on the intestinal uptake of vitamin B₁₂ bound to intrinsic factor (IF). PE had no effect on the pH in the small intestine and did not stimulate the uptake of unbound ⁵⁷CoB₁₂ by perfused rat intestinal segments. Preincubation of ⁵⁷COB₁₂-IF with a non-IF B₁₂- binder from human saliva (R-binder) reduced the uptake of ⁵⁷COB₁₂ from 18.5 pg per cm intestine ±3.4 S.E.M. to 7.8 ± 1.6 (p<0.02). PE abolished this inhibitory effect (p<0.05). The results indicate that PE corrects the malabsorption of vitamin B₁₂ in CPI by an effect on non-IF B₁₂-binders.

Key-words:

• Intestinal absorption
• pancreatic disease
• pancreatic extract
• vitamin B₁₂
• vitamin B₁₂ binding
• vitamin B₁₂ deficiency