| Project/Area Number |
10470344
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Obstetrics and gynecology
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| Research Institution | Yamanashi Medical University |
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Principal Investigator |
HOSHI Kazuhiko Yamanashi Medical University, School of Medicine, Department of Obstetrics and Gynecology, Professor, 医学部, 教授 (20111289)
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| Co-Investigator(Kenkyū-buntansha) |
NAGAI Seiichiro Yamanashi Medical University, School of Medicine, Department of Obstetrics and Gynecology, Assistant Professor, 医学部, 助手 (40291380)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥6,300,000 (Direct Cost: ¥6,300,000)
Fiscal Year 1999: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1998: ¥5,800,000 (Direct Cost: ¥5,800,000)
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| Keywords | fertilization / fertilizing ability / sperm / oocyte / progesterone / progesterone receptor / estrogen receptor / egg activation |
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| Research Abstract |
1. The participation to the sperm fertilizing ability acquisition of sex steroid hormones and analysis of mechanisms for the process/
Progesterone has been demonstrated to induce the acrosome reaction in the human spermatozoon via the cell surface membrane progesterone receptor (PR). However, the molecular identity of the membrane receptor has not been clarified yet. We identified a novel isoform (termed "isoform S") of the progesterone receptor mRNA (PR isoform S mRNA ,PR-S mRNA) which consisted of a previously unidentified 5' -untranslated sequence and the exon 4-8 of the intracellular PR gene from the human testicular cDNA library. The PR-S mRNA could encode the protein corresponding to the almost entire part of the hormone binding domain of the intracellular PR, termed "PR isoform S (PR-S)". The 5' -untranslated sequence of the message was confirmed to be derived from a novel exon (termed "exon S") by the genomic cloning. Moreover, the expression level of the PR-S mRNA was higher in
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the spermatozoon than that in the uterine endometrium.
Estrogen induces the influx of Ca++ into sperm cell, and this action is estimated with non-genomic action via the cell surface membrane estrogen receptor (ER), mo. We identified a novel isoform ( termed "isoform S" ) of the estrogen receptor mRNA (ER is form S mRNA ,Era -S mRNA) which consisted of a previously unidentified 5' -untranslated sequence and the exon 4-8 of the intracellular ER gene from the human testicular cDNA library. The ERα -S mRNA could encode the protein corresponding to the almost entire part of the hormone binding domain of the intracellular ER, termed "Era isoform S (ERα - S).
These results implied that the PR-S and ERα -S which were possibility expressed in the spermatozoon might be related to the cell surface membrane steroid hormone receptors.
2. Effect of sperm immobilization and demembranation on the oocyte activation rate in the mouse
To analyze the effect of the state of sperm membrane on the oocyte activation rate following intracytoplasmic sperm injection (ICSI), three types of human and mouse spermatozoa (intact, immobilized and Triton X-100 treated) were individually injected into mouse oocytes.
Following human sperm injection, the fastest and the most efficient oocyte activation and sperm head decondensation occurred when the spermatozoa were treated with Triton X-100. Intact spermatozoa were the least effective in activating oocytes. When mouse spermatozoa were injected into mouse oocytes, the rates of oocyte activation and sperm head decondensation within activated oocytes were the same irrespective of the types of sperm treatments prior to injection. Less
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