Ignar-Trowbridge D M, Nelson K G, Ross K A, Washburn T F, Korach K S, McLachlan J A
Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709.
J Steroid Biochem Mol Biol. 1991 Jul;39(1):131-2. doi: 10.1016/0960-0760(91)90021-v.
The possibility that estrogen receptors may exist in uterine plasma membranes was investigated by covalent labeling of estrogen receptors in mouse uterine cells with [3H]tamoxifen aziridine (TA). Isolated epithelial and stromal cells of immature mice were incubated with [3H]TA in the presence or absence of unlabeled tamoxifen, homogenized and separated into nuclear, cytosolic and microsomal fractions by differential centrifugation. These fractions were subjected to SDS-polyacrylamide gel electrophoresis and the proteins labeled covalently with TA were visualized by autoradiography. Proteins labeled specifically with [3H]TA were observed almost exclusively in the nuclear fraction of both epithelial and stromal cells. In contrast, very little labeled protein was detected in the cytosolic or microsomal fraction. Although these data do not preclude the possibility that estrogen binding sites are present in plasma membranes of uterine cells, this cellular fraction is definitely not labeled to a significant extent by [3H]TA. Thus, if membrane estrogen binding sites exist, their structural conformations may be different from that of nuclear estrogen receptors.
利用[3H]他莫昔芬氮丙啶（TA）对小鼠子宫细胞中的雌激素受体进行共价标记，研究雌激素受体是否可能存在于子宫质膜中。将未成熟小鼠的分离上皮细胞和基质细胞在有或无未标记他莫昔芬的情况下与[3H]TA一起孵育，匀浆后通过差速离心分离成核、胞质和微粒体部分。对这些部分进行SDS-聚丙烯酰胺凝胶电泳，并用放射自显影法观察与TA共价标记的蛋白质。几乎仅在上皮细胞和基质细胞的核部分观察到特异性被[3H]TA标记的蛋白质。相反，在胞质或微粒体部分检测到的标记蛋白很少。虽然这些数据并不排除子宫细胞质膜中存在雌激素结合位点的可能性，但该细胞部分肯定没有被[3H]TA大量标记。因此，如果存在膜雌激素结合位点，其结构构象可能与核雌激素受体不同。
