BIOLOGICAL EFFECTS AND SURVIVAL OF TRYPSIN-INHIBITORS AND THE AGGLUTININ FROM SOYBEAN IN THE SMALL-INTESTINE OF THE RAT

The survival in the rat small intestine of soybean agglutinin or Kunit z or-Bowman-Birk trypsin inhibitors was studied by SDS- and native pol yacrylamide gel electrophoresis, transblotting, trypsin inhibitor acti vity assays, sind immunochemical determinations. As the inhibitors wer e bound in enzyme complexes in the small intestine, functional assays were unsuitable. However, as free and bound inhibitors reacted similar ly with their antibodies, survival could be assayed by immunoblotting and ELISA. In addition to the mucosa-bound agglutinin, 8.6% of the ori ginal dose was free in the gut lumen and this, by moving further down in the small intestine, could have extended the wasteful gut growth fr om proximal to distal parts. Although only 4.8% of the Bowman-Birk inh ibitor survived, most (76%) of the Kunitz inhibitor remained immunoche mically intact. Accordingly, stimulation of pancreatic growth and enzy me secretion by the inhibitors, particularly the Kunitz, may have cont ributed to the total antinutritive effect of soybean.