Immunoactive trypsins in duodenal juice from children with gastrointestinal disorders.

Duodenal juice contains two trypsins, one anionic and one cationic at pH 8.6. To investigate their distribution, we studied fasting specimens of duodenal juice from 89 children with different gastrointestinal problems. The two trypsins were separately determined with electroimmunoassay parallel with determinations of total trypsin esterolytic activity and total protein. In 81 children with normal pancreatic function the ratio immunoactivity: esterolytic activity averaged 3.25:1. Anionic trypsin comprised an average 12% of immunoactivity: the average trypsin contribution to the total protein content was 37% for immunoactivity and 12% for esterolytic activity. These ratios were not influenced by age. Fourteen children with coeliac disease had significantly lower mean values for trypsins and total protein'. Eight children with pancreatic insufficiency had discrepant trypsin distribution, anionic trypsin being the dominant residuum in five of the eight.