THE EFFECT OF PREDNISONE THERAPY ON PLATELET MONOAMINE-OXIDASE AND PLASMA-CATECHOLAMINE LEVELS IN CHILDREN WITH ACUTE LYMPHOCYTIC-LEUKEMIA

Corticosteroid therapy is known to be associated with mood changes (es pecially depression) in children with acute lymphocytic leukemia (ALL) . The enzyme monoamine oxidase (MAO) degrades plasma catecholamines (e specially epinephrine and norepinephrine). Elevated levels of MAO and reduced levels of catecholamines have been associated with various beh avioral changes, especially depression. In this study, we evaluated pl atelet MAO activity and plasma catecholamine levels in children with A LL before and after a 4 week course of prednisone. There was a signifi cant 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) aft er prednisone therapy. It may be concluded that prednisone therapy in children with acute leukemia increases MAO activity and reduces catech olamine levels. The increased MAO activity may be related to increased enzyme synthesis or to enhanced catalytic properties of MAO by predni sone. All these factors may play a role in the behavioral changes asso ciated with prednisone therapy.