Shyamala G, Barcellos-Hoff M H, Toft D, Yang X
Life Sciences Division, Lawrence Berkeley Laboratory, University of California, Berkeley 94720, USA.
J Steroid Biochem Mol Biol. 1997 Nov-Dec;63(4-6):251-9. doi: 10.1016/s0960-0760(97)00128-3.
In normal mammary glands of both rodents and humans, progesterone promotes the proliferation of epithelial cells and several lines of evidence suggest that this action of progesterone may be mediated by progesterone receptor (PR). It is well established that normal mammary development involves a complex interplay between the epithelial cells and the surrounding fatty stroma. Furthermore, during mammary development, there is a change in both the relative proportion of epithelial cells and the steady-state levels of PR. Therefore, towards understanding the precise role of PR in mammary development, we have generated a highly sensitive antibody against mouse PR and examined its pattern of localization. Immunoreactive PR was detected only in the epithelial cells of the ducts while both the adipose and fibrous stroma surrounding these ducts were receptor negative. Similarly, PR mRNA was also associated only with the ductal epithelial cells. Approximately only 45-50% of the ductal cells were receptor positive and this distribution remained unchanged whether or not the tissues had been exposed to estrogen, suggesting that they may represent a distinct subpopulation. The potential significance of these findings to mammary development is discussed.
在啮齿动物和人类的正常乳腺中，孕酮可促进上皮细胞增殖，并且有多项证据表明，孕酮的这一作用可能由孕酮受体（PR）介导。众所周知，正常的乳腺发育涉及上皮细胞与周围脂肪基质之间复杂的相互作用。此外，在乳腺发育过程中，上皮细胞的相对比例和PR的稳态水平都会发生变化。因此，为了了解PR在乳腺发育中的精确作用，我们制备了一种针对小鼠PR的高灵敏度抗体，并检测了其定位模式。仅在导管的上皮细胞中检测到免疫反应性PR，而这些导管周围的脂肪和纤维基质均为受体阴性。同样，PR mRNA也仅与导管上皮细胞相关。大约只有45%至50%的导管细胞为受体阳性，无论组织是否暴露于雌激素，这种分布都保持不变，这表明它们可能代表一个独特的亚群。本文讨论了这些发现对乳腺发育的潜在意义。
