Thyroid hormone receptor

Protirelin (TRH) is an evolutionarily ancient neuropeptide, having its origin before the divergence of protostomes and deuterostomes, and may ancestrally have been involved in the control of postembryonic growth and reproduction. The effect of the thyrotropin-releasing hormone (Protirelin, TRH), one of the hypothalamic releasing hormones, on body temperature is investigated in the rat. Protirelin, in doses of 1, 5, 10 and 20 mg/kg, is injected intraperitoneally to male Wistar rats weighing 200-250 g. Protirelin causes a temporary rise in body temperature dose-dependently. The thyroidectomized rats injected 20 mg/kg of Protirelin which induces a significant hyperthermia in the sham-operated animals, fail to show a rise in body temperature. The present results suggest that a release of thyroid hormone might participate in the hyperthermic action of Protirelin.