Journal of investigative medicine : the official publication of the American Federation for Clinical Research
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The pituitary thyroid axis is frequently effected in human depression possibly due to alteration in hypothalamic thyrotropin releasing hormone (TRH) secretion. Since clinical recovery is associated with normalization of thyroid function, the direct effect of antidepressants on TRH expression in a well established fetal rat hypothalamic neuronal culture system was investigated. ⋯ This raises the possibility that the enhanced thyroid function in depression, which we postulate, may result in part from glucocorticoid stimulation of TRH gene expression, can be reversed by antidepressants through a direct effect on the TRH neuron. However, other mechanisms may need to be invoked in addition since basal TRH content was also reduced.