title: Reduction of blood glucose level by orexins in fasting normal and streptozotocin-diabetic mice.
abstract: Orexin-A and orexin-B are neuropeptides implicated in the maintenance of energy homeostasis. In the present study, we examined the effects of orexins on blood glucose levels in response to fasting in normal and streptozotocin-induced diabetic mice. After the injection of orexin-A and orexin-B (0.01-1 nmol/kg, i.v.), the blood glucose levels in both normal mice and diabetic mice in the fasting state decreased. In contrast, neither orexin-A nor orexin-B affected the glucose levels in the animals allowed free access to food. Intracerebroventricular administration of orexin-A and orexin-B was associated with glucose-lowering effects in fasting diabetic mice. The serum insulin level did not significantly change following the administration of orexin-A or orexin-B, in either the normal or the diabetic mice in the fasting state. These results demonstrate that orexins lower the blood glucose levels exclusively in the fasting state. The orexins may stimulate some neural and hormonal network and thereby promote blood glucose utilization.
authors.affiliation: Department of Clinical Pharmacology, Graduate School of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-0194, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsuneki
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Sugihara
authors.forename: Ritsu
authors.initials: R
authors.lastname: Honda
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Wada
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Sasaoka
authors.forename: Ikuko
authors.initials: I
authors.lastname: Kimura
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D002352:Carrier Proteins / Q000494:pharmacology* / Q000502:physiology; D003921:Diabetes Mellitus, Experimental / Q000097:blood* / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D005215:Fasting / Q000097:blood*; D007276:Injections, Intraventricular; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D051379:Mice; D009479:Neuropeptides / Q000494:pharmacology* / Q000502:physiology; D000068797:Orexins
chemical_list: D001786:Blood Glucose; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins