Peptides  >  Orexins
Orexins (hypocretins) are neuropeptides primarily localized in the hypothalamus and are implicated in the regulation of a variety of activities, including feeding behavior and energy balance. Orexins have also been found to be linked to idiopathic narcolepsy (excessive daytime sleepiness). Two homologous peptides, orexin-A (OXA) and orexin-B (OXB), are proteolytic cleavage products derived from a common precursor called prepro-orexin. Prepro-orexin is expressed in a specific population of neurons in and around the lateral hypothalamic area and is involved in the catecholaminergic and serotonergic feeding systems, playing a role in circadian feeding, sex differences, in feeding and spontaneous activity. Prepro-orexin mRNA level is up-regulated upon fasting, suggesting a physiological role for the peptides as mediators in the central feedback mechanism that regulates feeding behavior. Orexin expression is not obviously related to changes in body weight, insulin or leptin, but is stimulated under conditions of low plasma glucose in the absence of food. OXA and OXB are 33- and 28-residue peptides, respectively, and were first isolated from rat hypothalamus. OXA is completely conserved among human, rat, mouse, and bovine species and is found in the endocrine prancreas. Fasting activates OXA neurons in the lateral hypothalamic area and gut.

Ref: Cheng, SB. et al. Neurosci. Res. 46, 53 (2003); Bernardis LL. and LL. Bellinger, Neurosci. Biobehav. Rev. 20, 189 (1996); Sakurai, T. et al. Cell 92, 573 (1998); Cai, XJ. et al. Diabetes 48, 2132 (1999).
 Product Size Catalog # US$  
Orexin A, bovine, human, mouse, rat
Pyr - PLPDCCRQKTCSCRLYELLHGAGNHAAGILTL - NH2 (Disulfide bridge: 6 - 12 and 7 - 14)
1 mg AS-24470 $480
Orexin B, human  NEW 1 mg AS-65573 $255
Orexin B, mouse  NEW 1 mg AS-65574 $255
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