title: Tryptophan metabolism was accelerated by exercise in rat.
abstract: We have already reported that exercise activates kynurenine pathway. But, the mechanism for this activation by exercise is still unclear. Kynurenine is metabolized to NAD, which is an essential factor for energy metabolism. In this study, exercise on treadmill was loaded to rats until all-out and tryptophan metabolites and tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO) activities were determined in the blood, livers, and macrophages, respectively, in the exercise-loaded rats. The mean values of serum tryptophan concentration decreased from 92.6 +/- 6.0 nmol/ml to 52.4 +/- 10.2 nmol/ml (p<0.05) just after treadmill load. The serum kynurenine concentration had increased from 2.06 +/- 0.25 nmol/ml to 3.08 +/- 0.62 nmol/ml (p<0.005). And whole blood NAD concentration increased from 68.8 +/- 14.6 nmol/ml to 77.9 +/- 19.1 nmol/ml (p<0.005). These results showed that exercise activated the kynurenine pathway of tryptophan metabolism and made NAD which will be concerned with energy metabolism in mitochondria. Tryptophan-NAD pathway was initiated by cleavage of indole ring of tryptophan by TDO in the liver and IDO in many organs. We had also found that the exercise increase IDO activity of macrophages, but not TDO activity.
authors.affiliation: Department of Physiology, School of Health Sciences, Fujita Health University, Toyoake Aichi, 470-1192, Japan. yasitoh@fujita-hu.ac.jp
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ito
authors.forename: Reiko
authors.initials: R
authors.lastname: Yonekura
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Maruta
authors.forename: Takaaki
authors.initials: T
authors.lastname: Koike
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Nakagami
authors.forename: Katsumi
authors.initials: K
authors.lastname: Shibata
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Saito
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Nagamura
mesh_terms: D000818:Animals; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase; D007737:Kynurenine / Q000097:blood; D008099:Liver / Q000201:enzymology; D008264:Macrophages / Q000201:enzymology; D008297:Male; D005082:Physical Exertion / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D014364:Tryptophan / Q000097:blood / Q000378:metabolism*; D014366:Tryptophan Oxygenase / Q000378:metabolism
chemical_list: D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase; D007737:Kynurenine; D014364:Tryptophan; D014366:Tryptophan Oxygenase