Table 2 Mean levels of tryptophan, metabolites and indices of the relative activity at 3 metabolic stages in 4 subject groups (SD in parentheses)

Tryptophan *

μg/ml

11.82

(2.16)

10.78

(2.23)

12.49

(2.69)

11.84

(2.55)

Availability *

Index

12.75

(3.49)

11.56

(2.14)

13.51

(1.72)

13.10

(0.60)

Kynurenine

ng/ml

629.5

(98.5)

634.5

(132.3)

629.9

(83.3)

628.0

(85.1)

Breakdown^#

Index

0.054

(0.009)

0.060

(0.012)

0.051

(0.006)

0.054

(0.009)

Kynurenic acid

ng/ml

8.06

(2.08)

8.42

(3.25)

9.08

(2.17)

8.51

(2.50)

3OH-Kynurenine ^#

ng/ml

18.41

(4.43)

20.69

(5.05)

19.34

(3.66)

19.40

(3.65)

Neuroprotection

Index A (KA/3HK)

0.457

(0.139)

0.414

(0.141)

0.469

(0.071)

0.437

(0.085)

Neuroprotection

Index B (TR)

12.93

(3.038)

13.52

(4.961)

14.34

(2.624)

13.57

(3.772)

5-HIAA

ng/ml

12.08

(3.84)

11.84

(5.31)

13.97

(6.61)

13.79

(5.93)