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首页> 外文期刊>Journal of Cellular Physiology >Estrogen and estrogen plus progestin act directly on the mammary gland to increase proliferation in a postmenopausal mouse model.
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Estrogen and estrogen plus progestin act directly on the mammary gland to increase proliferation in a postmenopausal mouse model.

机译：雌激素和雌激素加黄体酮直接行动在乳腺增加扩散绝经后的小鼠模型。

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Hormone replacement therapy (HRT) with ovarian hormones is an important therapeutic modality for postmenopausal women. However, a negative side effect of HRT is an increased risk of breast cancer. Surgical induction of menopause by ovariectomy (OVX) in mice is an experimental model that may provide insights into the effects of hormone replacement therapy on the human breast. We have developed a mouse model of early and late postmenopausal states to investigate the effects of HRT on the normal mammary gland. The purpose of this study was to determine if HRT-induced proliferation was due to the direct action of the hormones on the mammary gland, or mediated systemically by hormones or growth factors produced elsewhere in the body. Estrogen (E) or E plus the synthetic progestin, R5020, were implanted directly into the mammary glands of early (1 week post OVX) and late (5 week post OVX) postmenopausal mice instead of administration by injection. We report that responses of early and late postmenopausal mice to implanted hormones were the same as those observed previously with systemically administered hormones. Implanted E conferred an enhanced proliferative response in the late postmenopausal gland characterized morphologically by enlarged duct ends. E+R5020 implants induced similar degrees of cell proliferation in both postmenopausal states but the morphological responses differed. Ductal sidebranching was observed in early postmenopausal mice, whereas duct end enlargement was observed in late postmenopausal mice. The differences in morphological response to E+R5020 in 5 week post OVX were associated with an inability of E to induce progesterone receptors (PR) in the late postmenopausal gland. The responses of the late postmenopausal glands to E and E+P were very similar to that observed previously in immature pubertal glands in ovary-intact mice. In pubertal mice, PR cannot be induced by E unless the mammary gland is pre-treated with EGF-containing implants. Similarly, herein pre-treatment of the late postmenopausal mammary gland with EGF-containing implants restored PR induction by E. Thus, EGF may determine the sensitivity of the mammary gland to E and E+P in late postmenopause and at puberty. Copyright 2001 Wiley-Liss, Inc.
机译：与卵巢激素替代疗法(HRT)荷尔蒙是一种重要的治疗方法绝经后妇女。荷尔蒙替代疗法的效果是一个增加乳腺癌的风险癌症。小鼠卵巢切除术(OVX)是一个实验模型可以提供洞察的影响激素替代疗法的人乳房。和绝经后晚期状态调查荷尔蒙替代疗法对正常乳腺的影响。本研究的目的是确定HRT-induced扩散是由于直接行动的乳腺激素,或调节系统由激素或增长身体其它部位的产生因素。(E)和E +合成黄体酮,R5020,直接植入到乳腺吗早期(1周后OVX)和后期(5周OVX)绝经后小鼠代替政府通过注入。绝经后小鼠反应的早期和晚期植入的激素水平是一样的观察之前与系统注射激素。加强后期增生性反应绝经后腺的特点形态学的放大管的目的。植入物诱导的细胞相似度扩散但在绝经后的状态形态不同的反应。分支是早期发现绝经后的小鼠,而管扩大在绝经后晚期老鼠。E + R5020形态反应的差异在5周后OVX与一个有关E无法引起孕激素受体在绝经后晚期腺(PR)。反应绝经后晚期腺E和E + P非常类似于观察以前在不成熟的青春期的腺体ovary-intact老鼠。由E除非乳腺预处理EGF-containing植入物。同样,这里的预处理绝经后与EGF-containing乳腺由e .因此,植入物恢复公关感应EGF可能决定乳房的敏感性腺在绝经后期年底E和E + P和青春期。

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