Author(s)

Hiroi Tomioka^1,2, Junichi Masuda³, Akikazu Takada^4*, Akira Iwanami¹

¹Department of Psychiatry, School of Medicine, Showa University, Tokyo, Japan.
²Department of Psychiatry, Showa University Northern Yokohama Hospital, Yokohama, Japan.
³Global Application Development Center, Shimadzu Corporation, Tokyo, Japan.
⁴International Projects on Food and Health (NPO), Tokyo, Japan.

Background: It is not well analyzed whether there are differences in plasma levels of tryptophan (TRP) metabolites between healthy control people (HC) and patients of major monopolar depression (MMD). Methods: Ultra high-speed liquid chromatography/mass spectrometry has been used for the simultaneous determination of plasma levels of tryptophan metabolites in depressive patients. Results: There are no significant differences between plasma levels of TRP between HC and MMD. Plasma levels of TRP of HC are higher in young men, young women, old men, and old women in this order. Serotonin (5-HT) levels are higher in MMD than HC. Plasma levels of 5-HIAA of HC are also higher than those of patients of MMD. Plasma levels of kynurenine (KYN) of healthy old men and old women are higher than those of young men and old women. Plasma levels of KYN are higher in old women and young men of MMD than those of HC. Conclusion: Plasma levels of 5-HT are higher in patients of MMD than those of HC, which may suggest that use of drugs inhibiting the 5-HT transportation may increase plasma levels of 5-HT in MMD.

Depression, Monopolar Depression, Bipolar Depression, Tryptophan, Serotonin, 5-Hydroxyindole Acetic Acid, Kynurenine, 3-Hydroxykynurenine, Kynurenic Acid, Anthranilic Acid, Xanthurenic Acid, Indole-3-Acetic Acid, SSRI (Selective Serotonin Reuptake Inhibitor), SNRI (Serotonin Norepinephrine Reuptake Inhibitor)

Tomioka, H. , Masuda, J. , Takada, A. and Iwanami, A. (2020) Differences of Plasma Levels of Tryptophan, Serotonin, 5-Hydroxyindole Acetic Acid, and Kynurenine between Healthy People and Patients of Major Monopolar Depression at Various Age and Gender. Food and Nutrition Sciences, 11, 431-441. doi: 10.4236/fns.2020.116031.