DISTRIBUTION OF THE BOWMAN BIRK PROTEASE INHIBITOR IN MICE FOLLOWING ORAL-ADMINISTRATION

In this study, the distribution of the soybean-derived Bowman Birk inh ibitor (BBI) in mice was examined. Mice received [I-125]BBI by oral ga vage and three hours later, the mice were sacrificed, the organs of in terest were carefully removed and the distribution of the inhibitor wa s determined. The bulk of labeled BBI was present in the luminal conte nts of the small and large bowel, urine and feces. Significant amounts of label were also observed in the serum, esophagus, stomach and inte stine, kidney, liver and lung. Analysis of tissue homogenates by gel f iltration chromatography revealed that the radioactivity eluted from t he column at the same position as the BBI standard indicating that the iodinated BBI was still intact. The chromatographically purified BBI was able to inhibit chymotrypsin indicating that functional protease i nhibitory activity was present. These results indicate that the BBI be comes widely distributed in mice 3 h after oral administration and tha t intact protease inhibitor is present in internal organs.