| Project/Area Number |
03454510
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
内分泌・代謝学
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| Research Institution | Gunma University |
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Principal Investigator |
KOJIMA Itaru Professor, Inst. of Endocrinology Gunma University, 内分泌研究所 教授 (60143492)
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| Co-Investigator(Kenkyū-buntansha) |
SHIBATA Hiroshi Assistant Professor, Inst of Endo. Gunma University, 内分泌研究所, 助手 (20235584)
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| Project Period (FY) |
1991 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥6,400,000 (Direct Cost: ¥6,400,000)
Fiscal Year 1992: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1991: ¥5,800,000 (Direct Cost: ¥5,800,000)
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| Keywords | activin A / inhibin / TGF-beta / growth / differentiation / autocrine / growth factor / 活性因子 / インスリン / 肝細胞 / アクチビン / 下垂体ホルモン / カルシウム |
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| Research Abstract |
1) Studies in Pituitary Cells: We studied the effect of activin A in human GH-producing pituitary adenoma cells in primary culture. Activin A stimulated FSH secretion in these cells and increased cytoplasmic free calcium concentration by augmenting calcium entry. 2) Studies in Fibroblasts: In Balb/c 3T3 cells, activin A inhibited cell-cycle progression induced by insulin-like growth factor-I (IGF-I). Activin did not affect calcium entry induced by IGF-I but significantly reduced IGF-mediated production of diacylgylcerol, which may be causally related to its action on cell-cycle progression. 3) Studies in Pancreatic Islet: In pancreatic islets, immunoreactivity of activin A existed in both A- and D-cells. Electron Microscopic analysis revealed that activin A and glucagon existed in the same secretory graniles in A-cells. Given that activin is a potent stimulant of insulin secretion, it is possible that activin A acts as a paracrine regulator of insulin secretion. 4) Studies in Hepatocytes: In cultured hepatocytes, activin A blocked DNA synthesis induced by EGF. Activin inhibited DNA synthesis by acting on it sown receptors. Hepatocytes produce significant amount of activin A when the growth is stimulated. Stimulatory action of EGF was enhanced when follistatin was included in culture medium, suggesting that endogenous activin A attenuates DNA synthesis induced by EGF.
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