The relationships between the cortisol responses to dexamethasone and to L-5-HTP, and the availability of L-tryptophan in depressed females.
In order to investigate the relationships between the hypothalamic-pituitary-adrenal (HPA)-axis activity, the central serotonergic neurotransmission, and the peripheral metabolism of l-tryptophan (L-TRP), the authors measured the following: the postdexamethasone cortisol values, the cortisol responses to 125 mg 5-hydroxy-L-tryptophan (L-5-HTP) orally, and the total L-TRP/competing amino acids (CAA) ratio in 64 depressed females. Severely depressed females showed significantly lower values for L-TRP/CAA, significantly higher postdexamethasone cortisol values, and cortisol responses to L-5-HTP as compared with minor depressives. Dexamethasone nonsuppressors showed significantly lower L-TRP/CAA values as compared with suppressors. The cortisol responses to dexamethasone were significantly and negatively correlated with the availability of L-TRP. The cortisol responses to L-5-HTP were not related to either the availability of L-TRP or to the postdexamethasone cortisol values.
Maes
M
M
Department of Psychiatry, University Hospital of Antwerpen Edegem, Belgium.
Vandewoude
M
M
Schotte
C
C
Maes
L
L
Martin
M
M
Scharpe
S
S
Blockx
P
P
D006916:5-Hydroxytryptophan; D000328:Adult; D003866:Depressive Disorder / Q000097:blood / Q000175:diagnosis* / Q000523:psychology; D003907:Dexamethasone; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects; D008875:Middle Aged; D010556:Personality Tests; D010913:Pituitary-Adrenal System / Q000187:drug effects; D011985:Receptors, Serotonin / Q000502:physiology; D014364:Tryptophan / Q000097:blood*
D011985:Receptors, Serotonin; D003907:Dexamethasone; D014364:Tryptophan; D006916:5-Hydroxytryptophan; D006854:Hydrocortisone