Evidence for separate binding sites for progesterone and RU486 in the chick oviduct.
Evidence for separate binding sites for progesterone and RU486 in the chick oviduct.
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雏鸡输卵管中黄体酮和 RU486 不同结合位点的证据。
DOI：
10.1016/0167-4889(86)90104-7
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
M. Agarwal
中科院分区：
文献类型：
--
作者：
V. Moudgil;G. Lombardo;C. Hurd;N. Eliezer;M. Agarwal
研究了合成类固醇米非司酮(RU38486-又称RU486)在鸡输卵管和小牛子宫制备的胞浆中的结合特性，并与孕酮和合成孕酮R5020的结合特性进行了比较。与[~3H]孕酮结合不同，在50 nM的配基浓度下，[~3H]RU486在输卵管胞浆中的结合不饱和。过量的RU486不能消除[~3H]孕酮的结合，用1000倍的过量孕酮处理鸡输卵管胞浆后，[~3H]RU486的结合被认为是不可替代的。显然，雏鸡输卵管胞浆具有两组独立的位置，分别与孕酮和RU486相互作用。此外，在37℃下孵育60min时，鸡输卵管胞浆中的[~3H]RU486结合保持不变；从DEAE-Sephacel中洗脱后，它显示出单一的离子形式，并在无盐和0.3M KCl5-20%蔗糖梯度中沉积在4 S地区。在小牛子宫胞浆中，两种类固醇表现出相似的结合特征。我们的结果提供了证据，证明鸡输卵管具有不同的结合部位，可以接受孕酮或RU486，但不是两者都接受，就像在小牛子宫中的情况一样。
Binding characteristics of synthetic steroid, mifepristone (RU38486 - also referred to as RU486), were examined in cytosol prepared from the chick oviduct and the calf uterus, and were compared with those of progesterone and synthetic progestin R5020. Unlike [3H]progesterone binding, the [3H]RU486 binding in the oviduct cytosol did not saturate at 50 nM ligand concentration. The [3H]progesterone binding could not be eliminated in the presence of excess RU486, and [3H]RU486 binding was seen to be indisplaceable upon pretreatment of the chick oviduct cytosol with a 1000-fold excess progesterone. It is apparent that the chick oviduct cytosol is endowed with two separate sets of sites which interact with progesterone and RU486 independently. Furthermore, [3H]RU486 binding in the chick oviduct cytosol remained intact when incubated for 60 min at 37°C; it exhibited a single ionic form upon elution from DEAE-Sephacel and the [3H]RU486-associated radioactivity sedimented in the 4 S region both in salt-free and 0.3 M KCl-containing 5–20% sucrose gradients. In the calf uterus cytosol, both steroids exhibited comparable binding profiles. Our results provide evidence that chick oviduct possesses distinct binding sites that accept either progesterone or RU486, but not both, as is the case in the calf uterus.