Thyrotropin-releasing hormone enhances event-related brain potentials and growth hormone release in man

Changes in contingent negative variation (CNV), a brain-evoked potential related in arousal, as well as in serum triiodothyronine (T3), thyroxine (T4), thyroid-stimulating hormone (TSH), prolactin (PRL), cortisol and growth hormone (GH) levels were recorded in 12 male volunteers receiving either thyrotropin-releasing hormone (TRH) or saline infusion. Only during TRH administration an increase in CNV (P less than 0.02) and, 30 min later, in GH (P less than 0.05) occurred; thyroid hormones and PRL increased as well, in the absence of any correlation with CNV areas. Cortisol was not affected by TRH. As dopamine (DA) agonistic drugs notoriously increase both CNV areas and GH levels and experimental evidence for prodopaminergic properties of TRH has accumulated in animal models, a possible explanation of the results here presented might be the activation of DA pathways by TRH also in the human.