Expression of the steroidogenic acute regulatory protein in the corpus luteum of the rabbit: Dependence upon the luteotropic hormone, estradiol-17 beta
Expression of the steroidogenic acute regulatory protein in the corpus luteum of the rabbit: Dependence upon the luteotropic hormone, estradiol-17 beta
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DOI：
10.1095/biolreprod55.4.868
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发表时间：
1996-10-01
影响因子：
3.6
通讯作者：
Stocco, DM
中科院分区：
文献类型：
--
作者：
Townson, DH;Wang, XJ;Stocco, DM
最近表征的线粒体蛋白，类固醇生成急性调节（星星）蛋白，作为类固醇生成的限速蛋白，促使我们调查是否星星在兔黄体中表达，以及星星的表达是否对雌二醇-17 β，促黄体激素在兔。在连续给予外源性雌二醇治疗至假孕第13天的家兔中（n = 9），免疫印迹分析显示星星的黄体表达稳定，校正积分光密度范围为8.5至9.7 U。这些家兔的血浆孕酮浓度（平均值+/- SEM）仍然升高（14.3 +/- 2.1 ng/ml）。相比之下，在实验的最后48和72小时内，在剥夺雌二醇的兔的黄体中星星的表达减少（分别为4.9 +/- 2.2和0.3 +/- 0.2 U，每组n = 3），并且与血浆孕酮的下降相关（分别为0.8 +/- 0.1和0.5 +/- 0.3 ng/ml）。雌二醇剥夺48小时后补充雌二醇（n = 3）刺激星星（10.3 +/- 2.6 U）的重现和血浆孕酮（10.4 +/- 4.9 ng/ml）的恢复。[S-35]对兔黄体中蛋白质的甲硫氨酸标记显示，响应雌二醇处理，特异性合成了星星蛋白的几种亚型。总的来说，这些观察结果与星星在调节雌激素促黄体作用以促进兔体内孕酮合成方面的拟议作用一致。
The recent characterization of the mitochondrial protein, Steroidogenic Acute Regulatory (StAR) protein, as a rate-limiting protein in steroidogenesis prompted us to investigate whether StAR is expressed in the rabbit corpus luteum and whether the expression of StAR is responsive to estradiol-17 beta, the luteotropic hormone in the rabbit. In rabbits treated continuously with exogenous estradiol through Day 13 of pseudopregnancy (n = 9), immunoblot analysis revealed that luteal expression of StAR was stable, ranging from 8.5 to 9.7 U of corrected integrated optical density. Plasma progesterone concentration (mean +/- SEM) remained elevated in these rabbits (14.3 +/- 2.1 ng/ml). In contrast, expression of StAR decreased in corpora lutea of rabbits deprived of estradiol for the last 48 and 72 h of the experiment (4.9 +/- 2.2 and 0.3 +/- 0.2 U, respectively, n = 3 per group), and was associated with a decline in plasma progesterone (0.8 +/- 0.1 and 0.5 +/- 0.3 ng/ml, respectively). Replacement of estradiol after 48 h of estradiol deprivation (n = 3) stimulated the reappearance of StAR (10.3 +/- 2.6 U) and the restoration of plasma progesterone (10.4 +/- 4.9 ng/ml). [S-35]Methionine labeling of proteins in rabbit corpora lutea revealed that several isoforms of StAR protein were specifically synthesized in response to estradiol treatment. Collectively, these observations are consistent with a proposed role for StAR in the mediation of the luteotropic effect of estrogen to promote the synthesis of progesterone in the rabbit.