Exocrine pancreatic function test by a synthetic peptide.

A new synthetic substance, N-Benzoyl-L-tyrosyl-p-aminobenzoic acid, is specially cleaved by pancreatic chymotrypsin after oral administration and the released p-aminobenzoic acid (P.A.B.A.) is absorbed and excreted in the urine. The P.A.B.A. recovery in the urine was examined to evaluate its diagnostic value as an exocrine pancreatic function test. The data permit the following conclusions: 1. There is a significant correlation between this test and maximal bicarbonate concentration, amylase output and volume of P.Z./C.C.K. secretin test. 2. More than one-half to two-thirds proximal or one-third distal of the pancreas must be removed before one can expect an abnormal result in this test. 3. This is a simple and useful test to detect exocrine pancreatic insufficiency of more than moderate degree but normal results may be obtained in minimal to mild exocrine pancreatic insufficiency. Only six of 11 cases (54.5%) with one abnormal factor of P-S test showed decreased P.A.B.A. recpvery, whereas 22 of 23 cases (95.7%) with two or three abnormal factors of P-S test showed decreased or borderline P.A.B.A. recovery.