STUDIES ON ELASTASE IN PANCREATIC DISEASES

Abstract

In order to develop a new enzymatic diagnoses of pancreatic diseases, elastolytic activity (elastase activity) in the duodenal juice was assayed using the specific synthetic substrate, and serum elastase l concentration was measured by radioimmunoassay.
The revised method using N-succinyl-(L-alanine)3-P-nitroanilide (SUC-(Ala)i-NA) as a synthetic substrate was shown to be more sensitive and useful than those using N-benzoyl-L-alanine-methyl ester (BAME) in determining elastase activity of the duodenal juice. The changes in the elastase activity were demonstrated to parallel with those of the amylase concentration in normal healthy subjects during the pancreozymin-secretin test (PS test) and a high correlation between the elastase output and the amylase output (P<0.001) was observed. Six out of 14 patients with questionable chronic pancreatitis, with normal results from the current PS test, showed definitely low elastase output. In 4 of the 6 cases, endoscopic retrograde pancreatography (ERP) and operative procedures were performed, resulting in definite findings of chronic pancreatitis.
Serum elastase l concentrations were significantly high in relapsing acute pancreatitis, chronic relapsing pancreatitis and in the early stage of pancreatic cancer, although serum amylase concentrations were only slightly high or were normal. In contrast, serum elastase l concentrations in calcifying chronic pancreatitis and in the terminal stage of pancreatic cancer were significantly low, whereas the serum amylase concentrations were within normal range.
These results suggest that patients with chronic pancreatitis tend to have more severe impairment in the secretion of elastase than of amylase in the PS test and that the measurement of serum elastase l offers a more specific and sensitive parameter of pancreatic function than does amylase estimation.