1989 Fiscal Year Final Research Report Summary
Study on the Role of Prolactin in Reproductive Physiology.
| Project/Area Number |
62570744
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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 |
Obstetrics and gynecology
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| Research Institution | The University of Tokyo |
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Principal Investigator |
TAKETANI Yuji Depart. of OB/GY associated. prof., 医学部(病)・産婦人科, 助教授 (10114539)
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| Co-Investigator(Kenkyū-buntansha) |
松岡 良 日立総合病院, 産婦人科, 医員 (80165787)
HAYASI Naoki Depart. of OB/GY Univ. of Tokyo. Senior staff., 医学部(病)・産婦人科, 助手 (60211489)
KUGU Koji Depart. of OB/GY Univ. of Tokyo. Senior staff., 医学部(病)・産婦人科, 助手 (20177976)
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| Project Period (FY) |
1987 – 1989
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| Keywords | Prolactin / gonadotropin / gonadotropin-releasing hormone(GnRH) / hypothalamus / anterior pituitary gland / endometriosis / inadequate luteal phase / infertility |
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| Research Abstract |
Modulatory effects of prolactin(PRL) on gonadotropin release were examined. An acute administration of OPRL to ovariectomized rats induced no influence on the content of gonadotropin-releasing hormone(GnRH) in the hypothalamus. However, the release of GnRH and gonadotropin were inhibited in rats given OPRL. The reduction in the gonadotropin release seems to be ascribable to the suppression of GnRH release. An acute elevation in PRL levels did not affect the pituitary responsiveness to GnRH. Thus, we deduced from these results that hyperprolactinemia inhibits the release of gonadotropin by primarily impairing the release of GnRH from the hypothalamus.
Then, the action of PRL on the secretion of donadotropin was investigated using a primary cell culture system of rat anterior pituitary gland. LH release was increased by adding PRL into culture media in a dose-dependent manner in the range between 10-1000 ng/ml. The stimulatory effect of PRL was further augmented in the presence of GnRH an
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d estradiol. PRL also caused an increase in FSH release. These data demonstrate that PRL stimulates the release of gonadotropin at the pituitary level, suggesting a paracrine mode of action of PRL in the anterior pituitary gland.
Clinically, the synchronous secretion of LH and PRL is frequently observed in normal cycling and hypogonadal women. Looking for the effects of GnRH on the PRL release, GnRH was given to women with normal menstruation and various menstrual disorders. This study offered such conclusion that GnRH occasionally alters the blood levels of PRL in either positive or negative manner depending on basal PRL levels.
In order seek the underlying mechanism of infertility associated with endometriosis, we demonstrate a close linkage of endometriosis and inadequate luteal function as evidenced by lower levels of progesterone at midluteal phase. There appears to be no correlation between the levels of progesterone and PRL. Therefore, conclusion is drawn that an aberrant secretion of PRL has no relation to the impaired corpus luteum function in endometriosis. Less
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Research Products
(9 results)
