Abstract
Corticosteroid therapy is known to be associated with mood changes (especially depression) in children with acute lymphocytic leukemia (ALL). The enzyme monoamine oxidase (MAO) degrades plasma catecholamines (especially epinephrine and norepinephrine). Elevated levels of MAO and reduced levels of catecholamines have been associated with various behavioral changes, especially depression. In this study, we evaluated platelet MAO activity and plasma catecholamine levels in children with ALL before and after a 4 week course of prednisone. There was a significant increase in platelet MAO activity, V(max) and Cl(i) values after prednisone therapy. Moreover, there was a significant decrease in the plasma levels of epinephrine and norepinephrine (but not dopamine) after prednisone therapy. It may be concluded that prednisone therapy in children with acute leukemia increases MAO activity and reduces catecholamine levels. The increased MAO activity may be related to increased enzyme synthesis or to enhanced catalytic properties of MAO by prednisone. All these factors may play a role in the behavioral changes associated with prednisone therapy.