2004 Fiscal Year Final Research Report Summary
RELATIONSHIP BETWEEN NEUROPEPTIDES AND NITRIC OXIDE IN REGULATING GROWTH HORMONE SECRETION
| Project/Area Number |
15590979
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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 |
Endocrinology
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| Research Institution | SHIMANE UNIVERSITY (2004)
Shimane Medical University (2003) |
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Principal Investigator |
KATO Yuzuru SHIMANE UNIVERSITY, SCHOOL OF MEDICINE, PROFESSOR, 医学部, 教授 (90030965)
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| Co-Investigator(Kenkyū-buntansha) |
MURAKAMI Yoshio SHIMANE UNIVERSITY, SCHOOL OF MEDICINE, ASSISTANT PROFESSOR, 医学部, 助教授 (10252909)
SOHMIYA Motoi SHIMANE UNIVERSITY, SCHOOL OF MEDICINE, INSTRUCTOR, 医学部, 講師 (50243431)
YAMANE Yuko SHIMANE UNIVERSITY, SCHOOL OF MEDICINE, ASSISTANT, 医学部, 助手 (20335566)
YAMAMOTO Masahiro SHIMANE UNIVERSITY, SCHOOL OF MEDICINE, ASSISTANT, 医学部, 助手 (50346392)
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| Project Period (FY) |
2003 – 2004
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| Keywords | GROWTH HORMONE / NEUROPEPTIDES / NITRIC OXIDE / PITUITARY / HYPOTHALAMUS / INSULIN-LIKE GROWTH FACTOR / CALCIUM CHANNNEL / REGULATION OF SECRETION |
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| Research Abstract |
Nitric oxide(NO) is a new factor to regulate a number of cell functions. However, a role of NO in the endocrine system remains to be elucidated. We previously reported that endogenous NO plays a role in regulating growth hormone(GH) secretion in GH_3 cells as autocrine and paracrine functions. We also found that NOS, a specific synthetase of NO, exists in pituitary GH producing cells. In normal subjects, intravenous infusion of TRH rather inhibited GH secretion although the mechanisms remain to be clarified. TRH may stimulate somatostatin secretion from the hypothalamus, which in turn inhibits GH secretion from the pituitary. Otherwise, TRH may stimulate NO release from surrounding gonadotroph cells in the pituitary, which inhibites GH secretion from GH produsing cells. On the other hand, GH binds to the vasucular endothels in which GH could modify the production of NO. NO also has an important role in the memory function of the hypocampus, in which NO synthesis is regulated by a number of neuropeptides including erythropoietin (EPO) and insulin-like growth factor (IGF-I).
In the present study, we clearly elucidated the following mechanisms in which 1)TRH stimulated NO production in GH_3 cells, 2)NO production in the pituitary cells in normal rats, 3)GH stimulated NO production in human endothelial cells, 4)the distribution of NOS and stimulation of NO production by EPO and IGF-I in rat hypocampus. These findings strongly indicate that NO plays an important role in regulating GH secretion, GH action and the memory function in the central nervous system.
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