Characterization of orexins (hypocretins) and melanin-concentrating hormone in genetically obese mice.
Orexins (hypocretins) and the melanin-concentrating hormone (MCH) are neuropeptides localized to the lateral hypothalamic area and are potential regulators of energy homeostasis. Using highly sensitive radioimmunoassay for orexins and MCH, we determined their contents in the lateral hypothalamus (LH) of genetically obese ob/ob and db/db mice and their controls, C57BL/6J and C57BL/KSJ. The orexin contents in the lateral hypothalamus significantly increased in the ob/ob mice, whereas the orexin contents significantly decreased in the db/db mice. Mature orexin-A and -B peptides were the major endogenous orexin molecules in the lateral hypothalamus. Conversely, the MCH contents in the lateral hypothalamus of both obese mice increased compared to the control mice. MCH contents in the lateral hypothalamus were two- to five-fold higher than that of orexin contents. These results suggest that the regulatory mechanism of orexin and MCH may be different in the genetically obese mice.
Mondal
Muhtashan S
MS
Third Department of Internal Medicine, Miyazaki Medical College, Kiyotake, Miyazaki 889-1692, Japan.
Nakazato
Masamitsu
M
Matsukura
Shigeru
S
D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D001835:Body Weight; D001923:Brain Chemistry / Q000502:physiology; D002352:Carrier Proteins / Q000032:analysis / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D007026:Hypothalamic Area, Lateral / Q000737:chemistry / Q000378:metabolism*; D007028:Hypothalamic Hormones / Q000032:analysis / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008543:Melanins / Q000032:analysis / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D009479:Neuropeptides / Q000032:analysis / Q000378:metabolism*; D009765:Obesity / Q000235:genetics / Q000378:metabolism*; D000068797:Orexins; D010907:Pituitary Hormones / Q000032:analysis / Q000378:metabolism*
D001786:Blood Glucose; D002352:Carrier Proteins; D007028:Hypothalamic Hormones; D047908:Intracellular Signaling Peptides and Proteins; D008543:Melanins; D009479:Neuropeptides; D000068797:Orexins; D010907:Pituitary Hormones; C019463:melanin-concentrating hormone