DIFFERENTIAL DEPLETION OF CYTOPLASMIC HIGH AFFINITY OESTROGEN RECEPTORS AFTER THE in vivo ADMINISTRATION OF THE ANTIOESTROGENS, CLOMIPHENE, MER‐25 AND TAMOXIFEN

Open Access
Publisher Website
Google Scholar
Abstract
The in vivo actions of the oestrogen antagonists clomiphene, MER‐25 and tamoxifen upon the cytosol oestrogen receptors prepared from amygdala, hypothalamus, pituitary and uterus of rats were studied 24 h after drug administration. There was a dose‐related depletion of cytosol oestrogen receptors. However, the uterine and pituitary receptors were consistently affected at a lower dose than were those from the brain. The ratios of the combined central ED50 to the combined peripheral ED50 were clomiphene 169 < MER‐25 19.2 > tamoxifen 2.13. The receptor changes were not related to biological activity monitored by serum luteinizing hormone levels and uterotrophic response. The possible role of these drug effects in the induction of ovulation and future developments are discussed.