title: Expression and changes of endogenous insulin-like growth factor-1 in neurons and glia in the gerbil hippocampus and dentate gyrus after ischemic insult.
abstract: In the present study, we focused upon expression and changes of endogenous insulin-like growth factor-1 (IGF-1) in the hippocampus of the Mongolian gerbil after ischemic insult. In sham-operated animals, IGF-1 immunoreactivity was absent from the hippocampus. IGF-1-immunoreactive (IR) neurons were detected at 12 h and 1 day after ischemic insult. In the hippocampal CA1 area, the IGF-IR neurons were non-pyramidal cells (GABAergic neurons). In the hippocampal CA2/3 areas, the IGF-1-IR neurons were pyramidal and non-pyramidal cells, and in the dentate gyrus the IGF-1-IR neurons were hilar neurons. Four days after ischemia-reperfusion, IGF-1 immunoreactivity disappeared from neurons, and significantly increased in astrocytes and microglia. These results suggest that the induction of IGF-1 in the CA1 area during the early stage (12-24 h after ischemic insult) is associated with the relative vulnerabilities of pyramidal glutamatergic neurons and non-pyramidal GABAergic neurons. The later increase (4 days after ischemic insult) of IGF-1 expression and protein content was found to promote the activities of astrocytes and microglia. These increases of IGF-1 in astrocytes and in microglia are associated with mechanisms that compensate for the effects of delayed neuronal death.
authors.affiliation: Department of Anatomy, College of Medicine, Hallym University, Chuncheon 200-702, South Korea.
authors.forename: In Koo
authors.initials: IK
authors.lastname: Hwang
authors.forename: Ki-Yeon
authors.initials: KY
authors.lastname: Yoo
authors.forename: Seung-Kook
authors.initials: SK
authors.lastname: Park
authors.forename: Sung-Jin
authors.initials: SJ
authors.lastname: An
authors.forename: Jae-Yong
authors.initials: JY
authors.lastname: Lee
authors.forename: Soo Young
authors.initials: SY
authors.lastname: Choi
authors.forename: Jung Hoon
authors.initials: JH
authors.lastname: Kang
authors.forename: Young-Guen
authors.initials: YG
authors.lastname: Kwon
authors.forename: Tae-Cheon
authors.initials: TC
authors.lastname: Kang
authors.forename: Moo Ho
authors.initials: MH
authors.lastname: Won
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000378:metabolism*; D018891:Dentate Gyrus / Q000737:chemistry / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D005849:Gerbillinae; D006624:Hippocampus / Q000737:chemistry / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000096:biosynthesis*; D008297:Male; D009457:Neuroglia / Q000737:chemistry / Q000378:metabolism*; D009474:Neurons / Q000737:chemistry / Q000378:metabolism*
chemical_list: D007334:Insulin-Like Growth Factor I