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Neuropeptide involved in neuroendocrine function including feeding and drinking behavior; two subtypes, A and B, exist.
Farlex Partner Medical Dictionary © Farlex 2012
Either of two neuropeptide hormones synthesized in the hypothalamus that regulate sleep and wakefulness and whose dysfunction causes narcolepsy. Also called hypocretin.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
A class of hypothalamic neuropeptide hormones that regulates sleep cycles and energy expenditure; they probably do not directly affect appetite, as was once believed.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
orexinOne of a pair of centrally-acting neuropeptides produced by the lateral hypothalamus where the sensation of hunger is mediated. Rats given orexin will eat about ten times the normal amount of food and rats starved for 48 hours have more than twice the normal concentrations of orexin. There are also specific receptors for the two orexins. These facts are being exploited in the design of drugs that can both stimulate and reduce appetite.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005