The development of the chymotryptic activity during postnatal life using the bentiromide test.

The chymotryptic activity was assessed in 40 newborns and infants age 3-180 days using the NBT-PABA test. Nine newborns were studied serially at different age periods. A group of 18 cystic fibrosis patients and a group of 17 healthy children served as pancreatic insufficient and pancreatic sufficient controls, respectively. The results demonstrate a gradual increase with age of chymotryptic activity, approaching the levels of older children at about 180 days. The newborns who were studied serially demonstrated an individual pattern of increase in their chymotryptic activity. In the first days of life, newborns show low chymotryptic activity similar to that found in cystic fibrosis patients.