1998 Fiscal Year Final Research Report Summary
Involvement of isulin-like growth factor-1 in the regulation of proliferation of lactotrophs
| Project/Area Number |
09671669
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Obstetrics and gynecology
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| Research Institution | Yamanashi Medical University |
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Principal Investigator |
HASHI Akihiko Yamanashi Medical University, Faculty of Medicine, Assistant Professor, 医学部, 講師 (10208431)
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| Project Period (FY) |
1997 – 1998
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| Keywords | anterior pituitary gland / lactotrophs / proliferation / IGF-1 / dopamine / estrogen |
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| Research Abstract |
1. Insulin and insulin-like growth factor-1 (IGF-1) stimulated proliferation of lactotrophs in a dose-dependent manner with maximal increases of 14- and 4-fold, respectively. Their actions appeared 16 h after treatment and thereafter became marked progressively.
2. The stimulatory action of IGF-1 on lactotroph proliferation was blocked by pretreatment with monoclonal antibody against to IGF-1, suggesting the specific action of JGF-1.
3. Both the mitogenic actions of insulin and IGF-1 were suppressed to similar degrees by the dopaminergic agonist bromocriptine.
4. Estradiol treatment stimulated proliferation of lactotrophs. The mitogenic action of es-tradiol was not influenced by pretreatment with antibody against IGF-1 that was sufficient to block the IGF- 1-induced proliferation.
5. PD98059, a selective inhibitor of the MAP kinase cascade that is involved in signal transduction of the mitogenic action of IGF-1, did not alter basal proliferation, but inhibited markedly the mitogenic action of estradiol.
6. Fixation with 4% paraformaldehyde for 20 min was optimal for immunostaining for IGF-1 receptors in anterior pituitary cells in culture. The best immunostaining was obtained by using anti-ICE-1 receptor antibody purchased from Oncogene.
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