L-deprenyl protects neurons in a number of in vivo and in vitro models and it has been postulated that it ameliorates some neurodegenerative disorders. Superoxide dismutase (SOD) is one of the enzymes responsible for the inactivation of oxygen free radicals, and one of the mechanisms of the effect of L-deprenyl is thought to act by induction of SOD. In this study, PC12 cells were used to study the effect of L-deprenyl on gene regulation of SOD and its interaction with nerve growth factor (NGF). The results show that NGF induces SOD mRNA in a dose-dependent manner and that a similar effect was produced by L-deprenyl. In addition, L-deprenyl potentiates NGF effects. This study demonstrates that both L-deprenyl and NGF may be involved in common antioxidative mechanisms and that L-deprenyl may interact with neurotrophic factors.