Lack of correlation between cerebrospinal fluid thyrotropin-releasing hormone (TRH) and TRH-stimulated thyroid-stimulating hormone in patients with depression.
BACKGROUND
It has been proposed that elevated central thyrotropin-releasing hormone (TRH) is associated with the blunted thyroid-stimulating hormone (TSH) response to TRH in patients with depression. Few studies have directly evaluated this relationship between central nervous system and peripheral endocrine systems in the same patient population.


METHODS
15 depressed patients (4 male, 11 female, 12 bipolar, and 3 unipolar) during a double-blind, medication-free period of at least 2 weeks duration, underwent a baseline lumbar puncture followed by a TRH stimulation test. Cerebrospinal fluid (CSF) TRH and serial serum TSH, free thyroxine, triiodothyronine, prolactin, and cortisol were measured. A blunted response to TRH was defined as a delta TSH less than 7 microU/mL.


RESULTS
There was no significant difference in mean CSF TRH between "blunters" (2.82 +/- 1.36 pg/mL) and "non-blunters" (3.97 +/- 0.62 pg/mL, p = .40). There was no evidence of an inverse relationship between CSF TRH and baseline or delta TSH. There was no correlation between CSF TRH and the severity of depression or any other endocrine measure.


CONCLUSIONS
These data are not consistent with the prediction of hypothalamic TRH hypersecretion and subsequent pituitary down-regulation in depression; however, CSF TRH may be from a nonparaventricular nucleus-hypothalamic source (i.e., limbic area, suprachiasmatic nucleus, brain stem-dorsal raphe) and thus, not necessarily related to peripheral neuroendocrine indices.
Frye
M A
MA
National Institute of Mental Health, Biological Psychiatry Branch, Bethesda, MD 20892, USA.
Dunn
R T
RT
Gary
K A
KA
Kimbrell
T A
TA
Callahan
A M
AM
Luckenbaugh
D A
DA
Corá-Locatelli
G
G
Vanderham
E
E
Winokur
A
A
Post
R M
RM
D000328:Adult; D001714:Bipolar Disorder / Q000134:cerebrospinal fluid*; D003866:Depressive Disorder / Q000134:cerebrospinal fluid*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000134:cerebrospinal fluid; D008297:Male; D011388:Prolactin / Q000134:cerebrospinal fluid; D013972:Thyrotropin / Q000134:cerebrospinal fluid* / Q000378:metabolism*; D013973:Thyrotropin-Releasing Hormone / Q000134:cerebrospinal fluid* / Q000494:pharmacology*; D013974:Thyroxine / Q000134:cerebrospinal fluid; D014284:Triiodothyronine / Q000134:cerebrospinal fluid
D014284:Triiodothyronine; D013973:Thyrotropin-Releasing Hormone; D011388:Prolactin; D013972:Thyrotropin; D013974:Thyroxine; D006854:Hydrocortisone