Lee K, Jung K, Cho J, Lee S, Kim HS, Shim JH, Lee SK, Kim M, Chu K.  High-Fat Diet and Voluntary Chronic Aerobic Exercise Recover Altered Levels of Aging-Related Tryptophan Metabolites along the Kynurenine Pathway.  Exp Neurobiol 2017;26:132-140.  https://doi.org/10.5607/en.2017.26.3.132