Postnatal adaptation of lipase- and trypsin-activities in duodenal juice of premature infants appropriate for gestational age.

In 17 very low birth weight and in 13 low birth weight infants appropriate for gestational age the activities of pancreatic lipase and trypsin, the pH value and the concentrations of total bile acids were measured in the preprandially aspirated duodenal juice between the 10th and the 40th day of postnatal life. The activities of both enzymes increased significantly with increasing postnatal age in both study groups but did not correlate with the gestational age between the 28th and 33rd week of gestation. The pH values were on a low but similar level in both study groups (mean for all infants 5.66 +/- 0.07), and there was no influence of the pH value on the activities of either pancreatic enzyme. The concentrations of total bile acids were also not different between the study groups (mean for all infants = 4.55 +/- 2.26 mmol/l) and no correlation could be found between the concentrations of total bile acids and the activities of both measured enzymes. The data suggest that the intrauterine development of the exocrine pancreas reaches a basal level by the 28th week of gestation and remains on this level up to the 33rd week of gestation. After birth there is a significant increase in enzyme activities for both studied enzymes.