Definition of orexin in English:

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Pronunciation: /ôˈreksin/

Entry from US English dictionary


Either of two hormones ( orexin-A or orexin-B) produced by the mammalian hypothalamus and functional in the regulation of appetite and sleep. Also called hypocretin.
Example sentences
  • For example, physical activity increased in rats when injected with orexin, a brain chemical associated with sexual arousal.
  • The lateral hypothalamus contains cells that secrete a protein neurotransmitter called ‘orexin’ or ‘hypocretin.’
  • Human narcolepsy generally stems from a shortage of the neurons, which produce the excitatory neurotransmitter known both as hypocretin and orexin.

For editors and proofreaders

Syllabification: o·rex·in

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