Hypertyraminemia in cirrhotic patients.

To evaluate the role of tyramine in hepatic disorders, we used a radioimmunoassay to study plasma concentration of tyramine in eight healthy subjects, 20 hospitalized patients without liver disease, and 13 cirrhotic patients of whom seven had hepatic encephalopathy. The effect of increasing dietary protein on tyramine level of cirrhotic patients was also assessed. No significant difference in plasma tyramine concentration was seen between normal subjects, 1.3 +/- 0.1 ng per milliliter (average +/- S.E.), hospitalized patients without hepatic disease (1.4 +/- 0.1 ng per milliliter) and cirrhotic patients without encephalopathy (2.7 +/- 0.5 ng per milliliter). However, the tyramine level in cirrhotic patients with encephalopathy, 6.4 +/- 0.1 ng per milliliter, was significantly (P less than 0.001) higher than in normal subjects or in cirrhotic patients without encephalopathy. Increasing dietary protein from 40 to 80 g per day raised fasting tyramine concentration by 30 to 70 per cent within three days in both encephalopathic and non-encephalopathic cirrhotic patients. Concentration of plasma tyramine in cirrhotic subjects was significantly correlated with that of plasma tyrosine (P less than 0.001).