Abstract

In order to disclose the mechanisms involving the elevation of serum 5'-nucleotidase (5'-N) activity in viral hepatitis patients, 5'-N activities in sera and liver tissues were examined in acute and chronic hepatitis patients and compared with normal controls. Serum 5'-N activities were 0.714 +/- 0.106 nanomoles adenosine/hour/mg protein in normal individuals, 1.162 +/- 0.479 in acute hepatitis patients, and 0.845 +/- 0.530 in chronic hepatitis patients. Tissue 5'-N activities were 298.8 +/- 86.7 in normal individuals, 598.1 +/- 198.3 in acute hepatitis patients, and 462.2 +/- 91.3 in chronic hepatitis patients. Serum 5'-N activity increased significantly in acute hepatitis patients, but not in chronic hepatitis patients. Tissue 5'-N activity increased in both acute and chronic hepatitis patients. The elevation of 5'-N activity in liver tissue was not an essential factor in the elevation of serum 5'-N levels. Other factors causing the release of 5'-N from liver tissue into the blood stream are thought to be more important. It is suggested that the shedding of plasma membrane with ecto 5'-N activity due to cell damage, or leakage of bile containing high 5'-N activity were causative factors.