[Trypsin and chymotrypsin activity during early postnatal development in the rat].

Activities of trypsin and chymotrypsin were studied in pancreas as well as in chyme from three departments of small intestine of rats of various age. Distinct decrease in content of chymotrypsinogen and increase in content of trypsinogen were observed in pancreas at first four days of rat life. In pancreas content of trypsinogen and chymotrypsinogen was as high in 4--20 days old rats as that one in 30-days old animals, maintained at definitive diet. Activity of trypsin and chymotrypsin was the same in duodenal contents of rats of both these groups. Activity of pancreatic proteinases was almost unaltered in chyme of jejunum intestine within first 20 days of life; it was twice increased to 30-days age. Trypsin and chymotrypsin were distinctly activated in chyme of ileum intestine with ageing. The highest activity of pancreatic proteinases was observed in chyme of ileum intestine. The data obtained suggest that rather intensive cavitary digestion of milk protein occurs in newborn rats.