This invention relates to Activity Dependent Neurotrophic Factor I complex (ADNF I complex) and polypeptides of this complex, which produce their neurotrophic effects through multiple proteases intrinsic to the ADNF I complex. The invention also relates to pharmaceutical compositions comprising ADNF I complex polypeptides, as well as methods for reducing neuronal cell death in vitro and in vivo, methods for treating oxidative stress in a patient, methods for reducing a condition associated with fetal alcohol syndrome in a subject, and methods of enhancing learning and memory both pre- and post-natally, all of which methods use the ADNF I complex polypeptides of the invention.