USE OF I131-LABELED PROTEIN IN THE STUDY OF PROTEIN DIGESTION AND ABSORPTION IN CHILDREN WITH AND WITHOUT CYSTIC FIBROSIS OF THE PANCREAS

Abstract

A method is described for evaluating protein digestion and absorption by measuring the fecal excretion of isotope after the administration of a test meal of I¹³¹-labeled protein. Application of this method to 10 children without gastrointestinal disase and to five with cystic fibrosis of the pancreas revealed the following: 1. Less than 6% of the ingested isotope was excreted in the feces of the "control" subjects. 2. A 10 to 40% (av. 22.5%) fecal excretion of the ingested isotope occurred in the children with cystic fibrosis of the pancreas. 3. A 50% decrease in the fecal excretion of isotope resulted in 2 of 4 children with cystic fibrosis of the pancreas when pancreatin was fed with the test meal. 4. One patient with cystic fibrosis of the pancreas, who after receiving pancreatin still excreted 40% or more of the ingested isotope in the feces, excreted only 8% when the test was repeated with prehydrolyzed protein.