Kynurenines with Neuroactive and Redox Properties: Relevance to Aging and Brain Diseases

Table 3

Changes in kynurenine pathway’s metabolites and enzymes with the age in rats [178, 180, 185, 248].

Metabolite/enzyme	Brain	Liver	Kidney
TRP	↓	↓	↓
TDO	↓	↓	↓
IDO	↑	↓	↓
KYN	↑	↓ at 12 months; No changes at 24 months	↓ at 12 months; ↑ at 24 months
KATs	↑	No changes	↑
KYNA	↑	No changes	↑
KMO		↓	↓
Kynureninase		↓	↓
3-Hydroxyanthranilate 3,4-dioxygenase		↑	↑
Aminocarboxymuconate-semialdehyde decarboxylase (ACMSD)		↑	↑
QPRT	↓	↓	↑
QUIN	↑	↑	↓ at 12 months; No changes at 24 months
PIC	↑	↑	↓ at 12 months; No changes at 24 months