BDNF and mood disorder: Furthermore, the kynurenine pathway is hypothesised to disrupt glutamate metabolism, leading to reduce astrocytic glutamate reuptake and stimulation of astrocyte glutamate release, leading to excess glutamate52,53 and reduced brain-derived neurotrophic factor (BDNF).54 Inflammatory effects on growth factors such as BDNF in the dentate gyrus of the hippocampus may affect learning and memory in patients with mood disorders.48