Hyperamylasemia and S-type isozyme dominance in liver cirrhosis.

To investigate the mechanisms of serum amylase abnormalities in liver disease, we determined serum amylase levels, S-type isozyme proportion, clinical symptoms, and laboratory data in 38 cases of histologically confirmed liver cirrhosis and 19 controls. Of the 12 patients who were hyperamylasemic (12/38, 32%), 5 showed S-type isozyme dominance (5/12, 42%), whereas in the 26 normoamylasemic cirrhosis patients, only 5 were S-type isozyme dominant (5/26, 19%). Isozyme percentages were significantly higher (P less than 0.01) in the dominant-S-type cases than in the controls, and S-type dominance was found more frequently in the hyperamylasemic than in the normoamylasemic cirrhosis cases. Only ascites and esophageal varices were observed more frequently as clinical symptoms in the dominant-S-type cases. Our results suggest that amylase is not produced in the human liver, but that the decreased clearance rate of amylase, especially the S-type isozyme, may be a cause of hyperamylasemia and S-type isozyme dominance in cirrhosis.