title: A Simple HPLC-MS/MS Method for Determination of Tryptophan, Kynurenine and Kynurenic Acid in Human Serum and its Potential for Monitoring Antidepressant Therapy.
abstract: The kynurenine pathway, in which tryptophan is metabolized to kynurenine and kynurenic acid, has been linked to depression. A rapid and highly reproducible liquid-chromatography-tandem mass spectrometry (LC-MS/MS) method were established for determining tryptophan, kynurenine and kynurenic acid in human serum. Biological samples were precipitated with methanol before separation on an Agilent Eclipse XDB-C18. The stable-isotope-labeled internal standards (kynurenine-13C415N and kynurenic acid-d5) were used for quantification. Detection was performed using multiple reaction monitoring in electrospray ionization mode at m/z 205.1→188.1 for tryptophan, m/z 209.1→146.1 for kynurenine, m/z 190.1→144.1 for kynurenic acid. Good linearity of analyte to internal standard peak area ratios was seen in the concentration range 1,000-50,000 ng/mL for tryptophan, 100-5,000 ng/mL for kynurenine and 1-60 ng/mL for kynurenic acid. Pooled drug-free human serum was purified using activated charcoal and the method was shown to be linear, with validation parameters within acceptable limits. The newly developed method was successfully used to determine concentrations of tryptophan, kynurenine and kynurenic acid in serum from 26 healthy volunteers and 54 patients with depression. Concentrations of tryptophan and kynurenine were lower in serum from depressed individuals than from healthy individuals.
authors: The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), 36 Mingxin Road, Guangzhou 510370, China.|The First Affiliated Hospital of Shantou University Medical College, 57 Changping Road, Shantou 515041, China.
authors: Li-Jun
authors: LJ
authors: Hu
authors: The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), 36 Mingxin Road, Guangzhou 510370, China.
authors: Xiao-Fang
authors: XF
authors: Li
authors: The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), 36 Mingxin Road, Guangzhou 510370, China.
authors: Jin-Qing
authors: JQ
authors: Hu
authors: The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), 36 Mingxin Road, Guangzhou 510370, China.
authors: Xiao-Jia
authors: XJ
authors: Ni
authors: The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), 36 Mingxin Road, Guangzhou 510370, China.
authors: Hao-Yang
authors: HY
authors: Lu
authors: Guangzhou Hospital of Traditional Chinese Medicine, Guangzhou University of Chinese Medicine, 16 Zhuji Road, Guangzhou 510405, China.
authors: Jia-Jia
authors: JJ
authors: Wang
authors: Guangzhou Xinhai Hospital , 167 Xingang West Road, Guangzhou 510300, China.
authors: Xiang-Ning
authors: XN
authors: Huang
authors: The First Affiliated Hospital of Shantou University Medical College, 57 Changping Road, Shantou 515041, China.
authors: Chao-Xian
authors: CX
authors: Lin
authors: The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), 36 Mingxin Road, Guangzhou 510370, China.
authors: De-Wei
authors: DW
authors: Shang
authors: The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), 36 Mingxin Road, Guangzhou 510370, China wenyuguangde@163.com.
authors: Yu-Guan
authors: YG
authors: Wen
mesh_terms: D000928:Antidepressive Agents / Q000097:blood / Q000627:therapeutic use; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid; D003863:Depression / Q000188:drug therapy; D016903:Drug Monitoring; D064368:Healthy Volunteers; D006801:Humans; D007736:Kynurenic Acid / Q000097:blood*; D007737:Kynurenine / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry; D014364:Tryptophan / Q000097:blood*
chemical_list: D000928:Antidepressive Agents; D007737:Kynurenine; D014364:Tryptophan; D007736:Kynurenic Acid