Degradation of insulin-like growth factors in small intestine of suckling rats

Insulin-like growth factors (IFGs), IGF-I and IGF-II, present in mammalian milk, play an important role during gastrointestinal tract development. In this study we identified and localized the activities of the common intesti nal proteolytic enzymes and investigated their degradation effect on IGFs. Results indicated that the enzymatic activities of chymotrypsin, trypsin, a nd elastase progressed from the lowest in the duodenum, to the highest in t he midjejunum, and declined in the ileum. Chymotrypsin exhibited the greate st IGFs degradation activities in neonatal intestinal lumen followed by ela stase. These data furnish a potential strategic design to supplement IGFs i nto milk formulas. (C) 2001 Published by Elsevier Science B.V.