Dynamic studies on estrogen response in fetal guinea pig uterus: effect of estradiol administration on estradiol receptor, progesterone receptor and uterine growth.

Abstract

AbstractThe uterus of the guinea pig fetus has been shown to respond to estradiol treatment by an increase in uterine wet weight and a stimulation of the progesterone receptor protein. A study of the kinetics of these two parameters of estrogen response in the fetal uterus was undertaken in order to correlate these responses with changes in the estrogen receptor. Administration of estradiol to pregnant guinea pigs (1 mg/kg/body weight) leads to a rapid stimulation of the progesterone receptor by 6h after treatment which reaches maximal values by 15.5h, which are increased 7-fold in estradiol-primed guinea pigs above values in untreated animals. The estradiol receptor undergoes rapid translocation from the cytosol into the nucleus by 1h after hormone treatment and is retained in the nucleus for at least 6h. At the same time, there is a 50% decrease in the total occupied and available estradiol receptor concentration at 6h after treatment. Estradiol treatment also provokes an increase in wet weight of the f...