al-Gubory K H, Machelon V, Nomé F
INRA, Station de physiologie animale, Unité d'endocrinologie de l'embryon, Joy-en-Josas, France.
C R Acad Sci III. 1995 Jan;318(1):91-8.
Previous studies in vivo provide evidence that extra-ovarian factors, currently unknown but nevertheless present and associated with pregnancy, directly prevent the growth of follicles beyond a diameter of 2 mm during the last trimester of pregnancy in the ewe. In the present study, the effect of charcoal-treated extract from sheep placenta on total aromatase activity, as determined by the conversion of [3H] androstenedione to estradiol and measurement of [3H] water, was investigated using primary culture of human granulosa cells in serum-free medium as a model. Addition of different doses (50, 150, 300 and 600 micrograms protein) of cotyledons extract of day 110 of pregnancy produced a dose-dependent diminution of granulosa cell aromatase activity in the absence of FSH. The maximal inhibition of aromatase activity occurred at a dose of 600 micrograms. These results showed that the cotyledons of late pregnancy contain a non-steroidal factor that inhibits basal aromatase activity in granulosa cells. Extracts prepared from cotyledons of days 90 and 110 of pregnancy but not extracts of days 50 and 70 significantly reduced basal aromatase activity in a dose-dependent manner. These results suggest that the production of the aromatase inhibiting factor increases with the advance of pregnancy. The aromatase inhibiting activity was lost after heating (80 degrees C, 30 min) or after treatment with trypsin (1 mg/ml) of cotyledons extract of day 110 of pregnancy, demonstrating the protein nature of the aromatase inhibiting factor. In conclusion, these experiments demonstrate that ovine placenta contains a heat- and trypsin-sensitive factor likely to be a protein which inhibits granulosa cell aromatase activity.
以往的体内研究表明，目前尚不清楚但确实存在且与妊娠相关的卵巢外因素，在母羊妊娠晚期可直接阻止直径超过2毫米的卵泡生长。在本研究中，以无血清培养基中培养的人颗粒细胞原代培养为模型，研究了经活性炭处理的绵羊胎盘提取物对总芳香化酶活性的影响，该活性通过[3H]雄烯二酮转化为雌二醇以及[3H]水的测量来确定。在无促卵泡素（FSH）的情况下，添加不同剂量（50、150、300和600微克蛋白质）的妊娠110天的子叶提取物，可使颗粒细胞芳香化酶活性呈剂量依赖性降低。芳香化酶活性的最大抑制作用出现在600微克的剂量下。这些结果表明，妊娠晚期的子叶含有一种非甾体因子，可抑制颗粒细胞中的基础芳香化酶活性。妊娠90天和110天的子叶制备的提取物，但妊娠50天和70天的提取物则不会，以剂量依赖性方式显著降低基础芳香化酶活性。这些结果表明，芳香化酶抑制因子的产生随着妊娠的进展而增加。妊娠110天的子叶提取物经加热（80摄氏度，30分钟）或用胰蛋白酶（1毫克/毫升）处理后，芳香化酶抑制活性丧失，这表明芳香化酶抑制因子具有蛋白质性质。总之，这些实验表明，绵羊胎盘含有一种对热和胰蛋白酶敏感的因子，可能是一种抑制颗粒细胞芳香化酶活性的蛋白质。
