The effect of duodenal juice on the intrinsic factor (IF) activity in gastric juice.

Duodenal juice, collected during basal conditions and during stimulation by pentagastrin, secretin, or cholecystokinin, was incubated with neutralized normal gastric juice. High concentrations of bile or proteolytic activity were accompanied by decrease of IF concentration. The inhibition was time- and temperature-dependent, increased significantly at low pH values, and seemed to be partly due to competitive inhibition by unspecific vitamin B12-binding activity. The results are of importance for measurements of IF concentration in gastric juice.