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 a n 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 dif ference between CSF TRH in patients (as a group or by diagnostic subtype) a nd control subjects (n = 90, F = 0.91, df = 2,84, P = 0.41). There was, how ever, 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 greate st gender difference in the bipolar group (t = 2.52, P<0.02). There wits 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.