CSF Thyrotropin-Releasing Hormone Gender Difference: Implications for Neurobiology and Treatment of Depression

In light of the postulated role of thyrotropin-releasing hormone (TRH) as an endogenous antidepressant, 56 refractory mood-disordered patients and 34 healthy adult control subjects underwent lumbar puncture for cerebrospinal fluid (CSF) TRH analysis. By two-way analysis of variance, there was no difference between CSF TRH in patients (as a group or by diagnostic subtype) and control subjects (n=90, F=0.91, df= 2,84, P=0.41). There was, however, a CSF TRH gender difference (females, 2.95 pg/ml; males, 3.98 pg/ml; n=90, F=4.11, df= 1,84, P<0.05). A post hoc t-test revealed the greatest gender difference in the bipolar group (t=2.52, P<0.02). There was no significant difference in CSF TRH in “ill” vs. “well” state (n=20, P=0.41). The role of elevated levels of CSF TRH in affectively ill men—or the role of decreased levels of CSF TRH in affectively ill women—remains to be investigated but could be of pathophysiological relevance.