Synthesis of 17beta-estradiol by isolated ovarian tissues of the pregnant rat: aromatization in the corpus luteum.
Synthesis of 17beta-estradiol by isolated ovarian tissues of the pregnant rat: aromatization in the corpus luteum.
复制标题
妊娠大鼠离体卵巢组织合成 17β-雌二醇：黄体中的芳香化。
作者：
D. Elbaum;P. Keyes
对怀孕大鼠的黄体进行孵育，以确定其体外产生17 -雌二醇和芳香化睾酮的能力。在妊娠第7、15和22天取出大鼠的黄体和非黄体卵巢组织，将这些组织立即冷冻或分别在37℃的培养基199中，在95% O2-5% CO2的气氛中孵育4小时。用高度特异性的放射免疫法定量组织和培养基中的β -雌二醇。在孵育过程中，雌二醇含量在非黄体组织中不断增加，而在孵育的黄体中则下降或保持不变。非黄体组织的合成，是18到400倍。黄体（5 - 25mg组织）与睾酮（200ng）在妊娠第7、15和22天孵育，在2.5 × 103pg /mg组织培养基中平均积累17β -雌二醇，相比之下，从同一卵巢取出的黄体组织在没有睾酮的情况下孵育的平均积累量为6pg /mg。孕15天大鼠黄体经(7α - 3h)-睾酮孵育后，15%转化为推定的（7α - 3h）17 -雌二醇，其分离方法与用于放射免疫测定的雌二醇分离方法相同。再结晶到恒定的比活性表明，分离的（3H）雌二醇的放射化学纯度很高（75%）。大鼠横膈膜肌和家兔黄体没有将睾酮芳构化为17 -雌二醇，而黄体放射孔在体外的非黄体卵巢组织中几乎是二醇。然而，黄体显示出惊人的芳香化睾酮的能力，这可能解释了怀孕期间大鼠黄体的高雌二醇含量。这种芳化系统和17 -雌二醇在黄体中的生理意义尚不清楚，但可能与雌二醇在妊娠大鼠中的促黄体作用有关。
Corpora lutea from pregnant rats were incubated to determine their ability to produce 17beta-estradiol and to aromatize testosterone in vitro. Corpora lutea and non-luteal ovarian tissues were removed from rats on days 7, 15, and 22 of pregnancy, and these tissues were immediately frozen or incubated separately in medium 199 at 37 C in an atmosphere of 95% O2-5% CO2 for 4 h. 17Beta-Estradiol in tissue and medium were quantified by a highly specific radioimmunoassay. The estradiol content ivnariably increased in non-luteal tissues during incubation, while it decreased or remained the same in incubated corpora lutea. The synthesis in non-luteal tissues, which was 18 to 400-fold greter. The incubation of corpora lutea (5 to 25 mg of tissue) with testosterone (200 ng) on days 7, 15, and 22 of pregnancy resulted in a mean accumulation of 17beta-estradiol in medium of 2.5 x 103 pg/mg tissue, compared with a mean value of 6 pg/mg for luteal tissue removed from the same ovaries and incubated without testosterone. The incubation of corpora lutea from 15-day pregnant rats with (7alpha-3H)-testosterone resulted in 15% conversion to presumptive (7alpha-3H)17beta-estradiol, which was isolated identically to estradiol isolated for radioimmunoassay. Recrystallization to constant specific activity revealed a high degree of radiochemical purity (75%) of the isolated (3H)estradiol. Rat diaphragm muscle and rabbit corpora lutea did not aromatize testosterone to 17beta-estradiol in amounts detectable by radioirpora lutea in vitro is virtually diol by non-luteal ovarian tissues. However,the corpora lutea show a striking capacity to aromatize testosterone, which might explain the high estradiol content of the rat corpora lutea during pregnancy. The physiological significance of this aromatizing system and of 17beta-estradiol in the corpus luteum is unknown but may be related to the luteotropic action of estradiol in the pregnant rat.