Increased brain concentrations of a neurotoxin, 3-hydroxykynurenine, in Huntington's disease

Concentrations of the neurotoxic tryptophan metabolite, 3-hydroxykynurenine, were determined in brain tissue taken post-mortem from patients with Huntington's disease and Alzheimer's disease. 3-Hydroxykynurenine was substantially and significantly increased in all three brain areas studied in Huntington's disease, but not significantly increased in the cortex in Alzheimer's disease, when compared to matched controls. These results demonstrate a possible dysfunction of tryptophan metabolism, via the kynurenine pathway, in Huntington's disease.