Pancreatic extract and the intestinal uptake of vitamin B12. I. Effect on the intestinal epithelium and the vitamin B12-intrinsic factor complex.

Pancreatic extract (PE) reduced the uptake of rat intrinsic factor (IF)-bound 57CoB12 by perfused rat intestinal segments (p is less than 0.02) as well as by isolated rat intestinal brush borders (p is less than 0.01). The inhibition was concentration-dependent. Preincubation of the brush borders with PE recular weight of the 57CoB12-IF complex, as well as the uptake of the complex by isolated intestinal brush borders, was unchanged after prolonged preincubation with PE. PE also inhibited the uptake of glucose by perfused intestinal segments (p is less than 0.01), but the morphology and idsaccharidase activity (p is greater than 0.5) of the intestinaleptihelium was unaltered. The results indicate that the inhibition may be due to interaction between the intestinal epithelium and PE.