THE INFLUENCE OF VASOACTIVE AGENTS ON METABOLIC-ACTIVITY OF THE LIVER IN CIRRHOSIS - A STUDY OF THE EFFECTS OF POSTERIOR PITUITARY EXTRACT, VASOPRESSIN, AND SOMATOSTATIN

The influence of posterior pituitary extract [PPE], vasopressin and somatostatin on hepatic elimination function was studied. Hepatic clearance and its 2 biological determinants, hepatic blood flow and metabolic activity (clearance Vmax/Km), were determined from hepatic indocyanine green elimination at steady-state in cirrhotic patients. I.v. infusion of PPE (oxytocin, 59%; vasopressin, 41%) at the constant rate of 0.3 U/kg per h decreased hepatic clearance (P < 0.05) and Vmax/Km (P < 0.05) but did not change hepatic blood flow. I.v. infusion of vasopressin (0.3 U/kg per h) decreased hepatic clearance (P < 0.05), Vmax/Km (P < 0.05) and hepatic blood flow (P < 0.05). The vasoactive agents used in the management of upper digestive bleeding in cirrhotic patients may have deleterious effects on the metabolic activity of the liver in addition to their effects on hemodynamics. The vasoactive substances apparently either increased the fraction of total hepatic blood which bypassed intact hepatocytes or directly impaired metabolic activity of hepatocytes. Reduction in the metabolic activity of the liver produced by vasoactive agents may have important implications in therapy of portal hypertension.