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前言 |
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排卵前5-6天, dominant follicle就開始漸漸移至ovarian
cortex, 並漸漸突出卵巢表面,由於follicle的快速脹大,
終於破裂而將"oocyte-cumulus complex"排出卵巢.
為何會有這一連串的變化, 終至"排卵",
吾人雖還不能完全理解, 但是一些伴隨的現象,
則可以提供我們某種程度的解釋. |
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LH-surge |
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高量的LH可以刺激follicle分泌prostaglandin,
而prostaglandin在促成排卵上, 佔很重要的角色,
換句話說, 如果給予prostaglandin synthesis
inhibitor, 將會抑制排卵. 一般來說, "排卵"大約出現在LH
surge之後24-36小時. |
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Lesser extent of FSH surge |
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FSH surge在排卵上雖然沒有LH重要,
但是動物實驗證實, 一隻hypophysectomized rat,
如果以FSH及LH刺激到有mature follicle之後,
不給予LH, 而給予高度純化的FSH,
仍然可以導致排卵. |
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Rapid increase in size of the follicle. |
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排卵前兩三天, follicle size可以很快速的從14-16mm增大至21-25mm,
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Change in composition of antral fluid |
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*increase proteoglycan--->increase in colloid
osmotic pressure |
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*increase plasminogen activator--->convert
plasminogen to plasmin---->dissolution of basal
membrane and perifollicular stroma--->stigma
formation---->rupture of follicle--->ovulation |
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*plasminogen activator同時也破壞cumulus cell
與其周圍的granulosa cell間的gap junction,使oocyte-cumulus
complex得以脫離follicle. |
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後語 |
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Stigma的破裂及卵子的流出,
事實上是很徐緩的動作,
並非像火山爆發般的噴出來, 排卵前的
intrafollicular pressure不但不高,其實很低. |
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