Abstract
Effects of various protease inhibitors on the intestinal absorption of insulin were studied by in situ closed small and large intestinal loops of rats. Sodium glycocholate, bacitracin, aprotinin, soybean trypsin inhibitor and camostat mesilate were used as protease inhibitor in this study. The absorption insulin from the gastrointestinal tract was evaluated by its hypoglycemic effect. When insulin without these protease inhibitors was administered into small or large intestinal loops, no marked hypoglycemic response was noted in both regions. However, a significant hypoglycemic effect was obtained after large intestinal administration of insulin containing various protease inhibitors, especially, 20mM Na-glycocholate, 20mM camostat mesilate when compared with controls. In contrast, we found little hypoglycemic effect following small intestinal administration of insulin with these protease inhibitors. These findings suggest that the coadministration of the protease inhibitors could be useful to improve the large intestinal absorption of insulin.
