1999 Fiscal Year Final Research Report Summary
Central mechanism controlling the expression of estrous behavior and its manipulation in the dog.
| Project/Area Number |
10839011
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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 |
動物臨床医学
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
INABA Toshio Univ. of Osaka Pref., Pref., Coll. of Agricul., Associate Professor, 農学部, 助教授 (00137241)
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| Co-Investigator(Kenkyū-buntansha) |
KAWATA Noritoshi Univ. of Osaka Pref., Coll. of Agricul., Research Associate, 農学部, 助手 (80221901)
TAMADA Hiromichi Univ. of Osaka Pref., Coll. of Agricul., Assistant Professor, 農学部, 講師 (10155252)
SAWADA Tsutomu Univ. of Osaka Pref., Coll. of Agricul., Professor, 農学部, 教授 (60081600)
TORII Ryuzo Siga Univ. of Mel. Sci., Inst. for Exp. Anim., Associate Professor, 医学部・付属動物実験施設, 助教授 (50106647)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Dog / Oestrus Induction / Gonadotrophin-Releasing Hormone / Hypothalamus / Anterior Pituitary / Estrogen Receptor mRNA / Estrogen / Luteinizing Hormone |
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| Research Abstract |
Central mechanism controlling the expression of estrous behavior and stimulatory effects of a sustained release formulation of the gonadotrophin-releasing hormone agonist (GnRH-A) on reproductive function in the dog were examined, and the following results were obtained.
1. An increase in the mean plasma levels of luteinizing hormone (LH) occurred from mid to late anestrus with the change in pulse patterns, followed by an increase in the mean plasma levels of estrogen and progesterone.
2. The increase in GnRH release from hypothalamus could be responsible for the increasing secretion of LH which occurs during the progression of anestrus.
3. Enhancement of hypothalamic estrogen receptor gene expression which may be regulated by estrogen might be one factor leading to the increased GnRH release in late anestrus.
4. During the course of anestrus pituitary GnRH receptor gene expression increased while the pituitary responded accordingly.
5. In proestrous bitches estrogen increased uterine sensitivity by increasing it's own receptor concentration, suggesting the preparation for estrus.
6. A single injection of sustained-release formulation of GnRH-A in anestrous bitches resulted in an induced heat.
These results suggest that, as a possible central mechanism controlling the expression of estrous behavior, the enhancement of hypothalamic estrogen receptor gene expression in late anestrus may lead to the increase in GnRH release, while pituitary responsiveness to thereby resulting in the resumption of ovarian and uterine activity with the return to estrus. They also indicate that microencapsulated LA can be useful in controlling the reproductive function in the dog.
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Research Products
(10 results)
