| Project/Area Number |
02808028
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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 |
物質生物化学
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| Research Institution | FAculty of Pharmaceutical Sciences, Nagasaki University |
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Principal Investigator |
SAKAKIBARA Ryuzo Faculty of Pharm. Sci. Nagasaki Univ. Associate Prof., 薬学部, 助教授 (30127229)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIGURO Masatsune Faculty of Pharm. Sci. Nagasaki Univ. Prof., 薬学部, 教授 (90038274)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1991: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1990: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Mouse oocyte / Oocyte maturation / Nonsecretory ribonuclease / Opioid peptide / Urinary peptides from pregnant women / Urinary peptides / RNase |
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| Research Abstract |
In mammals, the germinal vesicle of follicle-enclosed oocytes remains arrested at the dictyate stage of meiosis until the occurrence of a gonadotropin surge. Upon releasing the oocytes from the follicles in vitro, the meiotic process resumes, leading to a spontaneous germinal breakdown(GVBD)followed by the first polar body formation(PBF)of the oocytes, suggesting that oocyte maturation inhibitor(s)sustain the meiotic arrest of oocytes. In normal pregnancy, although hormonal levels of chorionic gonadotropin and estrogen are high, significant maturation of the oocytes and follicles do not occur for a long period, suggesting the possibility of a considerable increase in concentration of oocyte maturation inhibitor(s)in urine during pregnancy. The purpose of this study was to determine protein inhibitor(s)using denuded mouse oocytes in culture, if such inhibitor(s)are present in urine of pregnant women.
The results obtained from this study are as follows :
1. A protein inhibitor of PBF was purified from a uine of pregnant women by Sephadex G-100 and reversed-phase chromatographies. It was revealed that this protein possessed an ribonuclease activity and amino terminal sequence analysis showed that this protein is a product of a peculiar processing of a nonsecretory ribonuclease precursor. This protein was detected only in urine of pregnant women but not of normal men and women.
2. A fraction with molecular mass of less than 2, 000 daltons containing peptide inhibitor(s)of GVBD was prepared by gel filtration from pregnancy urine. The inhibitory activity of this fraction was partially reversed in the presence of naloxon, a potent opioid antagonist. Activity of this fraction obtained from pregnancy urine was significantly potent than same fractions obtained from normal women and men.
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