Functional examination of the pancreatic secretion with 4-(n-acetyl-l-tyrosyl)aminobenzoic acid.

The oral dose of 2g 4-(N-acetyl-L-tyrosyl) aminobenzoic acid was used to establish the secretion of pancreatic chymotrypsin after stimulation with Lundh's test-meal in 45 persons. By action of chymotrypsin 4-aminobenzoic acid is split in the small intestine. The extent of its excretion in the urine serves as an indicator of exocrine pancreatic secretion. The 4-aminobenzoic acid in the urine is estimated after acid hydrolysis by the diazotation reaction. The average value (x +/- SE) of 4-aminobenzoic acid excreted in an 8-hr urine sample amounts to 69.4 +/- 3.0% with the lower limit of the normal values (x - 2 SD) 49.6%. The corresponding values in patients with pancreatic maldigestion were significantly decreased (25.1 +/- 3.6%). Reduction of the collection period of urine to 6 hrs is sufficient for the demonstration of more advanced forms of pancreatic insufficiency. In cases of disturbances of absorption in the small intestine an extension of the urine collection period to 8 hrs is recommended. We consider this oral test to be a suitable screening method which can be conveniently used in out-patient practice.