ENZYME-IMMUNOASSAY OF LIVER-TYPE ARGINASE AND ITS POTENTIAL CLINICAL-APPLICATION

We developed an efficient enzyme-linked immunosorbent assay (ELISA) sy stem for measurement of human liver-type arginase in serum. A conjugat e of the Fab' fragment of anti-human liver (recombinant) arginase IgG and horseradish peroxidase was used as the second antibody. This assay is highly specific, sensitive, and reproducible, enabling us to detec t arginase at concentrations as low as several micrograms per liter wi thout any prior processing of serum. The reaction is linear up to 200 mug/L. The arginase concentration in serum, as determined by this meth od, increased markedly and temporarily at the time of surgical operati on or later injury to the liver. The increase was accompanied or follo wed by increases in serum concentrations of aspartate aminotransferase , alanine aminotransferase, and lactate dehydrogenase, suggesting that the arginase emerged from damaged hepatocytes. In view of a limited t issue distribution of liver-type arginase, our ELISA system may be use ful in diagnosis of various hepatic disorders as well as follow-up of postoperative conditions of patients.