Dynamics of in situ estrogen uptake by nuclei of individual pituitary and uterine cell types.

This investigation was carried out to examine the temporal aspects of nuclear retention of 3H-estrogen by individual target cell types of the rat uterus and pituitary. A quantitative dry autoradiographic-immunocytochemical method was used to measure relative 3H-estrogen uptake by nuclei of seven different target cell types 15 m, 1 h, 3 h and 7 h after injection of 3H-estradiol-17 beta. All five target cell types in anterior pituitary showed maximal nuclear retention at 15 m. Possible cell-type differences were noted in the rate of release of the isotope from nuclei. In the uterus maximal uptake, occurred between 1 h and 3 h after injection with stromal cells consistently concentrating more 3H-estrogen than luminal epithelial cells. These findings indicate possible differences between the mechanisms controlling nuclear retention of estrogen by the uterus and the pituitary.