Tryptophan Metabolism and the Reactive Metabolite Hypothesis for Human Cataract

2015 ◽  
pp. 83-86
Author(s):  
Roger J. W. Truscott ◽  
Andrew M. Wood
Keyword(s):  
Tryptophan Metabolism ◽  
Reactive Metabolite

scholarly journals Tryptophan Metabolism as a Pharmacological Target

2021 ◽  
Vol 42 (1) ◽  
pp. 60-73
Author(s):  
Morgane Modoux ◽  
Nathalie Rolhion ◽  
Sridhar Mani ◽  
Harry Sokol
Keyword(s):  
Tryptophan Metabolism ◽  
Pharmacological Target

scholarly journals Lack of Skeletal Muscle Serotonin Impairs Physical Performance

2021 ◽  
Vol 14 ◽  
pp. 117864692110031
Author(s):  
Marion Falabrègue ◽  
Anne-Claire Boschat ◽  
Romain Jouffroy ◽  
Marieke Derquennes ◽  
Haidar Djemai ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Endurance Training ◽  
Physical Performance ◽  
Depressive Disorders ◽  
Tryptophan Metabolism ◽  
Long Distance ◽  
Positive Effects ◽  
Tryptophan Metabolites ◽  
The Brain ◽  
Deficient Mice

Low levels of the neurotransmitter serotonin have been associated with the onset of depression. While traditional treatments include antidepressants, physical exercise has emerged as an alternative for patients with depressive disorders. Yet there remains the fundamental question of how exercise is sensed by the brain. The existence of a muscle–brain endocrine loop has been proposed: according to this scenario, exercise modulates metabolization of tryptophan into kynurenine within skeletal muscle, which in turn affects the brain, enhancing resistance to depression. But the breakdown of tryptophan into kynurenine during exercise may also alter serotonin synthesis and help limit depression. In this study, we investigated whether peripheral serotonin might play a role in muscle–brain communication permitting adaptation for endurance training. We first quantified tryptophan metabolites in the blood of 4 trained athletes before and after a long-distance trail race and correlated changes in tryptophan metabolism with physical performance. In parallel, to assess exercise capacity and endurance in trained control and peripheral serotonin–deficient mice, we used a treadmill incremental test. Peripheral serotonin–deficient mice exhibited a significant drop in physical performance despite endurance training. Brain levels of tryptophan metabolites were similar in wild-type and peripheral serotonin–deficient animals, and no products of muscle-induced tryptophan metabolism were found in the plasma or brains of peripheral serotonin–deficient mice. But mass spectrometric analyses revealed a significant decrease in levels of 5-hydroxyindoleacetic acid (5-HIAA), the main serotonin metabolite, in both the soleus and plantaris muscles, demonstrating that metabolization of tryptophan into serotonin in muscles is essential for adaptation to endurance training. In light of these findings, the breakdown of tryptophan into peripheral but not brain serotonin appears to be the rate-limiting step for muscle adaptation to endurance training. The data suggest that there is a peripheral mechanism responsible for the positive effects of exercise, and that muscles are secretory organs with autocrine-paracrine roles in which serotonin has a local effect.

Experimental Bilharzial Bladder Cancer: Tryptophan Metabolism in Nonhuman Primates Experimentally Infected With Schistosoma haematobium 2

1976 ◽  
Vol 56 (1) ◽  
pp. 101-104 ◽  
Author(s):  
Raymond R. Brown ◽  
Robert E. Kuntz ◽  
Richard A. Arend ◽  
Jerry A. Moore ◽  
Tao-Cheng Huang
Keyword(s):  
Bladder Cancer ◽  
Schistosoma Haematobium ◽  
Nonhuman Primates ◽  
Tryptophan Metabolism
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