Priming Action on Progesterone Receptor Synthesis by Estradiol and Tamoxifen in the 7,12-Dimethylbenz(a)anthracene-Induced Rat Mammary Carcinoma

Publisher Website
Google Scholar
Abstract
The priming action of estradiol and the antiestrogen tamoxifen (TMX) on progesterone receptor (PgR) synthesis has been investigated in the 7,12-dimethylbenz(a)anthracene-induced rat mammary tumor model testing different priming times. Rats received either TMX or estradiol benzoate (E2B) for 3 or 7 days. Tumors were assayed before and after treatment to investigate the changes produced by each treatment on estrogen receptor (ER) and PgR concentration. As expected, ER concentration decreased in each treatment group. PgR concentration increased after 3 days of either E2B or TMX administration, but decreased when treatment was prolonged to 7 days. These findings point out the time dependency of PgR induction in this tumor model, similarly to what was observed in other experimental and clinical conditions.