Subcellular distribution of estrogen receptor and progesterone receptor with and without specific ligand.

摘要: The estrogen receptor (ER) and progesterone (PR) content of cultured human breast carcinoma cells (MCF-7) was determined by biochemical assay, immunoblot analysis, immunohistochemical assay under varying conditions hormonal stimulation. ER PR in cytosolic nuclear extracts varied with steroid treatment. However, both the amount distribution each these virtually same when binding analyses. Two immunocytochemical parameters (staining intensity proportion stained) correlated quantitative analyses PR, but not subcellular distribution. When MCF-7 were grown for 4 days charcoal-stripped serum without phenol red, 93% total found cytosol (10 mM KCl), whereas short-term treatment 5 nM estradiol resulted appearance 82% extract (400 KCl). With either cell only staining observed. Progesterone undetectable any method. After estradiol, strongly induced (50-fold) as all three methods. As observed ER, 95% absence a progestin. Short-term ORG 2058, synthetic progestin, 42% extract. strong presence or These findings are consistent current view receptors present at least two forms. One these, unoccupied form receptor, is easily removed from nucleus hypotonic buffers during homogenization process appears other steroid-occupied form, more tightly bound to components nuclei vigorous extraction conditions.