1991 Fiscal Year Final Research Report Summary
Induction of thyroid C cell function and its mechanism.
| Project/Area Number |
02670141
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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 |
Human pathology
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| Research Institution | Wakayama Medical College |
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Principal Investigator |
KAKUDO K. Wakayama Med Coll, Pathology, Professor, 第2病理, 教授 (00112037)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEKOSHI S. Tokai Univ Med Sch, Pathol, assistant, 医学部・病理学, 助手 (70216878)
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| Project Period (FY) |
1990 – 1991
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| Keywords | C cell / Thyroid / Cell differentiation / Tumor differentiation / Secretion / Hormone synthesis / Lysosome |
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| Research Abstract |
For the purpose of studying effects of synthetic salmon calcitonin (TZ-CT) on CT synthesis and cell cycle of rat thyroid C cell, the following three experiments were carried out :
In experiment #1, effects of long term administration of TZ-CT on C cell population were evaluated immunohistochemically. Administration of TZ-CT 30IU/kg and 12OIU/kg for 53 weeks caused a dose-dependent, statistically significant reduction of the C cell population without the alteration of serum calcium levels. Electron microscopic examination showed no significant ultrastructural changes in C cells of both experimental and control groups.
In experiment #2, administration of TZ-CT 0.5IU/kg and 10OIU/kg for a short term (14 days) caused dose-dependent reduction of CT and CT-mRNA in the rat thyroid.
In experiment #3, effects of a short term administration of TZ-CT on C cell cycle were investigated. Administration of TZ-CT 0.4IU/kg and 40IU/kg for 15 days induced dose-dependent suppression of S phase C cell ratio to total C cells without decrease of C cell to the total thyroid cell ratio. These results may suggest that exogenous TZ-CT induces negative feedback to synthesis of CT and the proliferation of C cells of the thyroid.
Ultraviolet (254nm, 5J/m^2) on poorly differentiated C cell tumor line (HMCa) resulted in increased CT production after 96 hours, while over lOJ/m^2 ultraviolet resulted in cell degeneration.
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