Estradiol administration to newborn guinea pigs (30 ng/g body wt) provokes an 84 ± 10% and 145 ± 10% (means ± SE) increase of tamoxifen-specific binding site (site B) in the uterine cytosol and in the 0.6 M KCl nuclear extract, respectively, 48 hr after hormone administration. The simultaneous injection of progesterone (15 μg/g body wt) with estradiol antagonizes this estrogen-induced increase of site B. Parallel modifications of estrogen receptor are observed following the same estradiol treatment: after translocation to the nuclear fraction, cytoplasmic estrogen receptor is replenished 24 hr after hormone administration with a net increase of 60 ± 10% (mean ± SE) after 48 hr. The increase of estrogen receptor is also antagonized by the simultaneous administration of progesterone. It is concluded that the levels of both tamoxifen-specific binding site and estrogen receptor are modulated by estradiol and progesterone in the neonatal uterus of guinea pig.
|Number of pages||3|
|Publication status||Published - 1983|
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism