Uterine proteins influenced by estrogen exposure. Analysis by two-dimensional gel electrophoresis

Two-dimensional gel electrophoresis has been utilized as a technique to investigate uterine protein patterns and protein distribution after estrogen administration. A combined in vivo stimulation, in vitro labeling technique was devised to investigate these questions. Animals were first primed in vivo with estrogen for 2 h to activate the normal early response to hormone and to stimulate protein synthesis. Tissue was removed and protein labeling occurred for 4 h with [35S]methionine. Tissue was then re-exposed in vitro to either estrogen or saline for an additional 1 h. Subfractionation of the uterine tissue and analysis of labeled proteins by two-dimensional gel electrophoresis has indicated the disappearance of some proteins from the cytoplasmic compartment and the appearance of other proteins in the nuclear fraction of estrogen-exposed samples. These findings suggest that in the mouse uterus, estrogen influences protein synthesis and also a redistribution of these proteins into various cellular fractions where they may act to elicit estrogen action.