Differential diagnosis of maldigestion and malabsorption of fat. II. Comparison of 131I-triolein with 14C-triolein in normal, pancreatic juice-deficient, short bowel and bile-deficient dogs.

To determine whether or not purified 131I-triolein produces the same behavior as 14C-triolein in the intraluminal phase, and to assess whether or not 0.10 +/- 0.02 of the Digestion-Absorption Index (DAI) obtained from clinical cases is an adequate value for differentiating maldigestion from malabsorption of fat, dogs, pancreatic juice-deficient, short bowel and bile-deficient were prepared. Both the pancreatic juice-deficient and bile-deficient groups indicated a high fecal excretion of 14C- and 131I-radioactivity, and the short bowel group indicated a moderate fecal excretion of fat. Daily fecal fat levels in each group were in parallel to the 3-day fecal excretion of radioactivity. However, the Digestive-Adsorption Index of the pancreatic juice-deficient group of 0.602 in 14C and 0.620 in 131I, and indicated that a considerable portion of the ingested triolein was excreted into the feces without hydrolysis. DAI in the short bowel group were 0.020 in 14C and 0.022 in 131I, and in the bile-deficient group, the indices were 0.031 in 14C and 0.021 in 131I. Both latter groups showed a malabsorptive defect. Additionally, the Digestion-Absorption Index of the pancreatic juice-deficient group was higher than 0.10 +/- 0.02 of the clinical borderline mentioned in the foregoing paper, and that of the other two groups was lower. Therefore, this borderline may represent adequate values for the differentiation of fat malassimilation. On the other hand, it was confirmed that 14C-triolein and 131I-triolein showed similar behavior in the intraluminal phase, and that the 131I-triolein test was adequate for clinical testing for fat digestion and absorption.