Endurance exercise increases skeletal muscle kynurenine aminotransferases and plasma kynurenic acid in humans

Am J Physiol Cell Physiol. 2016 May 15;310(10):C836-40. doi: 10.1152/ajpcell.00053.2016. Epub 2016 Mar 30.


Physical exercise has emerged as an alternative treatment for patients with depressive disorder. Recent animal studies show that exercise protects from depression by increased skeletal muscle kynurenine aminotransferase (KAT) expression which shifts the kynurenine metabolism away from the neurotoxic kynurenine (KYN) to the production of kynurenic acid (KYNA). In the present study, we investigated the effect of exercise on kynurenine metabolism in humans. KAT gene and protein expression was increased in the muscles of endurance-trained subjects compared with untrained subjects. Endurance exercise caused an increase in plasma KYNA within the first hour after exercise. In contrast, a bout of high-intensity eccentric exercise did not lead to increased plasma KYNA concentration. Our results show that regular endurance exercise causes adaptations in kynurenine metabolism which can have implications for exercise recommendations for patients with depressive disorder.

Keywords: endurance exercise; kynurenic acid; kynurenine aminotransferases; skeletal muscle.

Publication types

  • Controlled Clinical Trial

MeSH terms

  • Exercise / physiology*
  • Humans
  • Kynurenic Acid / blood*
  • Male
  • Muscle, Skeletal / physiology*
  • Physical Conditioning, Human / methods
  • Physical Conditioning, Human / physiology*
  • Physical Endurance / physiology*
  • Transaminases / metabolism*
  • Up-Regulation / physiology
  • Young Adult


  • Transaminases
  • kynurenine-oxoglutarate transaminase
  • Kynurenic Acid