title: Decline in glucokinase activity in the arcuate nucleus of streptozotocin-induced diabetic rats.
abstract: Glucokinase (GK) is known to be the critical glucose sensor of pancreatic B-cells. However, the localization and functional role of GK in the brain remains to be elucidated. In this study, we measured both the activity and mRNA level of GK in the hypothalamic nuclei and the cortex of rats injected intraperitoneally with streptozotocin or vehicle. GK activity was measured by a fluorometric assay; and the GK mRNA level, by use of the real-time reverse transcription polymerase chain reaction. GK activity in vehicle-treated rats was high in the arcuate nucleus, moderate or low in the ventromedial nucleus, lateral hypothalamic area, and paraventricular nucleus, and very low in the cortex. The order of GK mRNA level was almost the same as that of GK activity. GK activity and GK mRNA level only in the arcuate nucleus of streptozotocin-treated rats at 7 d, but not at 2 d, after treatment were lower than those of vehicle-treated rats. The results suggest that prolonged hyperglycemia induced by diabetes decreased the activity of GK in the arcuate nucleus.
authors.affiliation: Laboratory of Neuropsychopharmacology, Graduate School of Environmental and Human Sciences, Meijo University, Tempaku-ku, Nagoya 468-8503, Japan. q0391504@ccmailg.maijo-u.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishio
authors.forename: Yukiyasu
authors.initials: Y
authors.lastname: Toyoda
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hiramatsu
authors.forename: Taku
authors.initials: T
authors.lastname: Chiba
authors.forename: Ichitomo
authors.initials: I
authors.lastname: Miwa
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000201:enzymology*; D001786:Blood Glucose / Q000032:analysis; D015153:Blotting, Western; D002540:Cerebral Cortex / Q000201:enzymology*; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology*; D005941:Glucokinase / Q000096:biosynthesis / Q000378:metabolism*; D007328:Insulin / Q000097:blood; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013311:Streptozocin
chemical_list: D001786:Blood Glucose; D007328:Insulin; D012333:RNA, Messenger; D013311:Streptozocin; D005941:Glucokinase