1995 Fiscal Year Final Research Report Summary
PHYSIOLOGICAL ROLES OF INSULIN-LIKE GROWTH FACTOR I ON THE PROLIFERATION OF MOUSE PITUITARY CELLS
| Project/Area Number |
06640866
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
生物形態・構造
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| Research Institution | OKAYAMA UNIVERSITY |
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Principal Investigator |
TAKAHASHI Sumio OKAYAMA UNVERSITY,Faculty of Science, Professor, 理学部, 教授 (90144807)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Pituitary / Insulin-like growth factor I / Proliferation / Growth factor / Mouse |
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| Research Abstract |
The present study was aimed to calrify the physiological roles of insulin-like growth factor-I (IGF-I) in the mouse pituitary glands. In the mouse pituitary glands, IGF-I containing cells and cells expressing IGF-I type I receptor were studied by in situ hybridization and immunohistochemical methods. Somatotrophs contained IGF-I and IGF-I mRNA,indicating that IGF-I was synthesized in somatotrophs. IGF-I receptors were also detected in somatotrophs. IGF-I inhibited growth hormone (GH)-releasing hormone-induced GH release in a monolayr-cultured system, indicating that IGF-I directly acts at the somatotroph level. In the same culture system, IGF-I and insulin stimulated the proliferation of pituitary cells. Epidermal growth factor (EGF) also stimulated the proliferation. These growth factor-induced proliferation was inhibited by administration of genistein, tyrosine kinase inhibitor. Estrogen with insulin treatment stimulated the proliferation, suggesting that "cross-talk" of estrogen-associated mechanism and insulin-associated one. Thus, the pituitary growth was regulated by not only steroid hormone, but also pituitary-derived growth factors. Estrogen increased pituitary IGF-I mRNA level. Estrogen effect on the proliferation was inhibited by EGF-receptor blocker RG 13022. Therefore, these findings suggest that estrogen action is mediated by IGF-I and/or EGF.IGF-I and EGF play physiological roles in an autocrine or paracrine manner in the pituitary gland.
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Research Products
(15 results)
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[Publications] Yoshikawa, T., Uozumi, T., Kawamoto, K., Arita, K., Ito, A., Takahashi, S.: "Characteristics of prolactin secretion in normal and estrogen-treated pituitaries of rats at the single cell level-Analysis by reverse hemolytic plague assay -." Endocrine Journal. 42. 235-243 (1995)
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[Publications] Yoshikawa, M., Uozumi, T., Kawamoto, K., Arita, K., Ito, A.and Takahashi, S.: "Characteristics of prolactin secretion in normal and estrogen-treated pituitaries of rats at the single cell level" -Analysis by reverse hemolytic plaque assay-.Endocrine J.42. 235-243 (1995)
Description
「研究成果報告書概要(欧文)」より
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[Publications] Takeuchi, S., Suzuki, H., Hirose, S., Yabuuchi, M., Sato, C., Yamamoto, H.and Takahashi, S.: "Molecular cloning and sequence analysis of the chick melanocortin 1-receptor gene." Biochim.Biophys.Acta. (in press).
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「研究成果報告書概要(欧文)」より
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