Progesterone stimulates DNA synthesis and lobulo-alveolar development in mammary glands in ovariectomized mice

✍ Scribed by Karen Plaut; Rhonda Maple; Erika Ginsburg; Barbara Vonderhaar

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 348 KB
• Volume: 180
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/(sici)1097-4652(199908)180:2<298::aid-jcp17>3.0.co;2-v

✦ Synopsis

The objective of this study was to determine whether sustained progesterone (P) use in the absence of estrogen could influence mammary development in mice. Three-week-old intact or ovariectomized mice were primed with subcutaneous (s.c.) cholesterol (C), estrogen (E), P, or estrogen and progesterone (E/P) together. Nine days after priming, mammary glands were removed and incubated as a whole organ in media supplemented with various combinations of lactogenic hormones. After 5 days in whole organ culture, glands were removed and end buds, alveolar buds and lobulo-alveoli were quantified. Glands from mice primed with C or E developed significantly less lobulo-alveoli than glands from mice primed with P or E/P. While the development was greater in animals treated with E/P compared to those treated with P, it was clear that P in the absence of E could still induce lobulo-alveolar development. We have shown in this paper that P, in the absence of E, can stimulate cell proliferation during priming. Subsequently, the P primed glands can differentiate in response to lactogenic hormones.