[The behaviour of serotonin in blood, the activity of monoaminooxidase in serum and of 5-hydroxyindoloacetic acid in twenty-four hour urine in patients with viral hepatitis (author's transl)].

The level of serotonin in blood, the activity of MAO in serum and the value of 5-HIAA in 24 hour urine were estimated in 76 patients with viral hepatitis divided according to clinical parameters into three groups (mild, mild to severe and severe clinical course). A statistically significant increase of serotonin level in blood compared with the healthy control group was found. Highest values were observed in patients with the severe form of viral hepatitis. Decreased values of 5-HIAA in 24 hour urine in the early course of the disease showed a tendency to increase in later examinations. The activity of MAO in serum was significantly lowered in all clinical forms of viral hepatitis.