Haslam S Z
Anatomy Department, Michigan State University, East Lansing 48824.
Endocrinology. 1988 Feb;122(2):464-70. doi: 10.1210/endo-122-2-464.
Current in vivo and in vitro data indicate that progesterone (P) is required for epithelial proliferation in mammary glands of adult mice. P receptors (PgR) in adult mammary glands are under estrogenic regulation. By contrast in immature, pubertal 5-week-old mice, PgR are present only in low concentration and cannot be increased by estrogen (E). Having identified two different mammary gland developmental states with differing PgR compositions, the purpose of the present studies was to investigate the roles of E-dependent and -independent PgR in epithelial cell proliferation. DNA histoautoradiography was used to quantitate the effect of P on DNA synthesis; hormonal effects on mammary gland morphology were also assessed. The results demonstrate the P, rather than E, has a major role in stimulating epithelial DNA synthesis in the adult mammary gland. The morphological correlate of P's stimulatory effect on cell proliferation was increased ductal side-branching. We postulate that P is acting via E-dependent PgR and that one important way in which E promotes epithelial cell proliferation in adult tissue is by its ability to increase PgR concentration. In the immature mammary gland E rather than P is primarily responsible for stimulation of epithelial cell proliferation at this developmental stage. It appears likely that the absence of a predominant, P-mediated cell proliferative effect is related to the lack of E-dependent PgR.
目前的体内和体外数据表明，成年小鼠乳腺上皮细胞增殖需要孕酮（P）。成年乳腺中的孕酮受体（PgR）受雌激素调节。相比之下，在未成熟的5周龄青春期小鼠中，PgR仅以低浓度存在，且不能被雌激素（E）增加。在确定了两种具有不同PgR组成的乳腺发育状态后，本研究的目的是探讨雌激素依赖性和非依赖性PgR在乳腺上皮细胞增殖中的作用。采用DNA组织放射自显影法定量P对DNA合成的影响；还评估了激素对乳腺形态的影响。结果表明，在成年乳腺中，刺激上皮细胞DNA合成的主要是P而非E。P对细胞增殖的刺激作用在形态学上的相关表现是导管侧支增多。我们推测P通过雌激素依赖性PgR发挥作用，并且雌激素促进成年组织中上皮细胞增殖的一个重要方式是其增加PgR浓度的能力。在未成熟乳腺中，在这个发育阶段，主要是E而非P负责刺激上皮细胞增殖。缺乏主要的、由P介导的细胞增殖效应似乎与缺乏雌激素依赖性PgR有关。
