Early exposure of the rat mammary gland to estrogen and progesterone blocks co-localization of estrogen receptor expression and proliferation
in Journal of EndocrinologySearch for other papers by L Sivaraman in
Current site
Google Scholar
PubMed
Search for other papers by SG Hilsenbeck in
Current site
Google Scholar
PubMed
Search for other papers by L Zhong in
Current site
Google Scholar
PubMed
Search for other papers by J Gay in
Current site
Google Scholar
PubMed
Search for other papers by OM Conneely in
Current site
Google Scholar
PubMed
Search for other papers by D Medina in
Current site
Google Scholar
PubMed
Search for other papers by BW O'Malley in
Current site
Google Scholar
PubMed
An early single full-term pregnancy induces a long-lasting protective effect against mammary tumor development in humans and rodents. This protective effect can be mimicked in rats by short-term administration of estrogen and progesterone hormones prior to carcinogen administration. The hormones of pregnancy are able to induce a proliferative block upon carcinogen challenge that is not observed in the age-matched virgin. We wished to determine whether carcinogen is needed to induce a paracrine-to-autocrine shift of proliferation in steroid receptor positive cells or if such a cell population already exists in the age-matched virgin mammary gland. Here we show that estrogen receptor positive (ER+) proliferating cells are rare in the developing mammary gland of the virgin rat but represent the majority of the proliferating cells in the mature (96-day-old) mammary gland of the virgin rat. As the majority of the proliferating cells before carcinogen challenge were ER positive, the ER+ proliferating cells in the mature mammary gland may represent the target cells for carcinogen-induced transformation. Importantly, prior exposure of the mammary gland to pregnancy levels of estrogen/progesterone blocked this positive association. This ability to block the proliferation of the ER+ cells may be one factor by which pregnancy induces protection against breast cancer.
Journal of Endocrinology is committed to supporting researchers in demonstrating the impact of their articles published in the journal.
The two types of article metrics we measure are (i) more traditional full-text views and pdf downloads, and (ii) Altmetric data, which shows the wider impact of articles in a range of non-traditional sources, such as social media.
More information is on the Reasons to publish page.
| Sept 2018 onwards | Past Year | Past 30 Days | |
|---|---|---|---|
| Full Text Views | 241 | 155 | 7 |
| PDF Downloads | 79 | 30 | 12 |
Online ISSN: 1479-6805
Print ISSN: 0022-0795
Strengthening biomedical communities
to advance science and health
CONTACT US
Bioscientifica Ltd | Starling House | 1600 Bristol Parkway North | Bristol BS34 8YU | UK
Bioscientifica Ltd | Registered in England no 3190519