Quantitative evaluation of serum pancreatic isoamylases in cystic fibrosis.

The amylase in sera of 20 patients with cystic fibrosis of the 
pancreas (CFP), 17 of whom had pancreatic insufficiency (PI), and of 
34 normal control subjects was separated into its pancreatic and salivary 
components and quantitated. Electrophoretic separation was achieved on polyacrylamide disc gels 
with subsequent sectioning of the gel columns. The amylase content in 
international units per liter (IU/L.) was obtained for each section by 
the insoluble blue starch substrate method. The mean total serum amylase 
of the CFP patients with PI was significantly lower than the 
control group. A highly significant decrease was found when the pancreatic 
isoamylase was considered alone. The salivary isoamylase level remained essentially the 
same. Three patients with CFP but without PI demonstrated higher than 
normal pancreatic amylase values in the serum. These patients may be 
in an early stage of a progressive involvement of the pancreas 
in which there is an increased release of amylase. This method 
of electrophoretic separation and quantitation of the serum amylase is sensitive 
and efficient and allows the simultaneous processing of multiple specimens. The 
results obtained agree with previously published ratios of serum isoamylases. Our 
method should be valuable in the study of other diseases of 
the exocrine pancreas and salivary glands. 