1240 PLATELET MONOAMINE OXIDASE (MAO) ACTIVITY IN REYE'S SYNDROME (RS)

Abstract

In patients with RS we have shown that MAO activity was significantly reduced in liver and tyramine, dopamine, norepinephrine, epinephrine, and octopamine were increased in plasma, urine, and cerebrospinal fluid. The purpose of the present study was to determine whether generalized MAO dysfunction is a metabolic abnormality associated with RS. Platelet and liver MAO activities were evaluated by radioenzymatic technique in RS and control patients. Platelet MAO activity was significantly decreased (p<0.025) in RS patients (n=13) [3.3 ± 2.4 nmoles of [3H]4-hydroxy-phenylacetic acid formed x (mg protein)−1 × hr−1] when compared to control patients without liver disease (n=8) [9.8 ± 2.5 nmoles] and in non-RS liver disease patients (n=9) [9.1 ± 2.0 nmoles]. Following recovery platelet MAO levels in RS patients were not significantly different from controls. In contrast, there were no significant differences between hepatic MAO activities in RS patients and those without liver disease or non-RS liver disease. Conclusion: 1) reduced platelet MAO activity is a specific abnormality in RS and represents generalized mitochondrial dysfunction; 2) the pattern of MAO activities in platelet and liver may differentiate RS from other hepatopathologic states; 3) the disturbance of MAO activity may be responsible for hypercatecholaminemia and neurologic dysfunction in RS patients.