Limitations in the Diagnostic Value of Serum Leucine Aminopeptidase

ON the basis of the hydrolysis of L-leucylglycine, Fleisher and his associates1 , 2 reported striking elevations of leucine aminopeptidase in serum of patients with hepatocellular disease as contrasted with those having obstructive jaundice. By means of a colorimetric method3 with the substrate, L-leucyl-2-naphthylamide, Rutenburg and his co-workers suggested that elevated leucine aminopeptidase activity in urine was a prominent finding in neoplastic disease4 and in serum was particularly helpful in diagnosing carcinoma of the pancreas.5 6 7 This was so since a normal serum level was observed to constitute strong evidence against the presence of carcinoma of the pancreas with or without associated jaundice. . . .