Exp Neurobiol 2017; 26(3): 132-140
Published online June 30, 2017
© The Korean Society for Brain and Neural Sciences
Keon-Joo Lee1,2, Keun-Hwa Jung1,2*, Joo-Youn Cho3, Soon-Tae Lee1,2, Hwa Suk Kim3, Jun Hwa Shim3, Sang Kun Lee1,2, Manho Kim1,2 and Kon Chu1,2*
1Department of Neurology, Seoul National University Hospital, Seoul 03080, 2Program in Neuroscience, Neuroscience Research Institute of SNUMRC, College of Medicine, Seoul National University, Seoul 03080, 3Department of Clinical Pharmacology & Therapeutics, Seoul National University College of Medicine and Hospital, Seoul 03080, Korea
Correspondence to: *To whom correspondence should be addressed.
Keun-Hwa Jung, TEL: 82-2-2072-4901, FAX: 82-2-3672-7553
Kon Chu, TEL: 82-2-2072-1878, FAX: 82-2-3672-4949
Tryptophan metabolites regulate a variety of physiological processes, and their downstream metabolites enter the kynurenine pathway. Age-related changes of metabolites and activities of associated enzymes in this pathway are suggestable and would be potential intervention targets. Blood levels of serum tryptophan metabolites in C57BL/6 mice of different ages, ranging from 6 weeks to 10 months, were assessed using high-performance liquid chromatography, and the enzyme activities for each metabolic step were estimated using the ratio of appropriate metabolite levels. Mice were subjected to voluntary chronic aerobic exercise or high-fat diet to assess their ability to rescue age-related alterations in the kynurenine pathway. The ratio of serum kynurenic acid (KYNA) to 3-hydroxylkynurenine (3-HK) decreased with advancing age. Voluntary chronic aerobic exercise and high-fat diet rescued the decreased KYNA/3-HK ratio in the 6-month-old and 8-month-old mice groups. Tryptophan metabolites and their associated enzyme activities were significantly altered during aging, and the KYNA/3-HK ratio was a meaningful indicator of aging. Exercise and high-fat diet could potentially recover the reduction of the KYNA/3-HK ratio in the elderly.
Keywords: tryptophan metabolites, kynurenine pathway, aging, voluntary chronic aerobic exercise, high-fat diet