AUTHOR=Messina Antonietta , De Fusco Carolina , Monda Vincenzo , Esposito Maria , Moscatelli Fiorenzo , Valenzano Anna , Carotenuto Marco , Viggiano Emanuela , Chieffi Sergio , De Luca Vincenzo , Cibelli Giuseppe , Monda Marcellino , Messina Giovanni TITLE=Role of the Orexin System on the Hypothalamus-Pituitary-Thyroid Axis JOURNAL=Frontiers in Neural Circuits VOLUME=10 YEAR=2016 URL=https://www.frontiersin.org/journals/neural-circuits/articles/10.3389/fncir.2016.00066 DOI=10.3389/fncir.2016.00066 ISSN=1662-5110 ABSTRACT=

Hypocretin/orexin (ORX) are two hypothalamic neuropeptides discovered in 1998. Since their discovery, they have been one of the most studied neuropeptide systems because of their projecting fields innervating various brain areas. The orexinergic system is tied to sleep-wakefulness cycle, and narcolepsy is a consequence of their system hypofunction. Orexinergic system is also involved in many other autonomic functions such as feeding, thermoregulation, cardiovascular and neuroendocrine regulation. The main aim of this mini review article is to investigate the relationship between ORX and thyroid system regulation. Although knowledge about the ORX system is evolving, its putative effects on hypothalamic-pituitary-thyroid (HPT) axis still appear unclear. We analyzed some studies about ORX control of HPT axis to know better the relationship between them. The studies that were analyzed suggest Hypocretin/ORX to modulate the thyroid regulation, but the nature (excitatory or inhibitory) of this possible interaction remains actually unclear and needs to be confirmed.