title: Cytosol and nuclear estrogen and progesterone receptors in the rabbit endocervix.
abstract: This report describes the measurement of estrogen and progesterone receptors in cytosols and nuclear fractions from endocervical tissue components. Unoccupied cytosol estrogen receptor levels as determined by Scatchard analysis of [3H]-estradiol binding data indicated a single class of high affinity binding sites for the epithelial-stromal complex (KD = 0.74 x 10(-9) M). Binding was specific for estrogen (estradiol greater than estriol greater than estrone) and unaffected by desoxycorticosterone, dihydrotestosterone and progesterone. Assays for total estrogen receptor verified that 71.6 +/- 5.3% of this 8S estrogen receptor is in the epithelial-stromal complex while the remaining approximately 28% is localized in the stroma and fibromuscular wall, with the cells of the complex containing the highest receptor concentration. In 5-day pseudopregnant and ovariectomized rabbits compared to estrous rabbits there was a 50% decrease in the cytosol estrogen receptor in the epithelial-stromal complex and a 30% decrease in the concentration of nuclear receptor. Cytosol and nuclear progesterone receptors were measured as an indicator of estrogen action in the rabbit endocervix. Cytosol progesterone receptor concentrations (fmol/mg DNA) in 5-day pseudopregnant and ovariectomized animals were reduced to approximately 35% of the concentration in estrous animals. Nuclear progesterone receptor concentrations decreased 65% in 5-day pseudopregnant and 90% in ovariectomized animals suggesting decreased receptor synthesis. Collectively these data support the concept that the rabbit endocervix may be directly regulated by estrogens.
mesh_terms: D000818:Animals; D002369:Castration; D002467:Cell Nucleus / Q000032:analysis; D002584:Cervix Uteri / Q000032:analysis*; D003600:Cytosol / Q000032:analysis; D004971:Estrus; D005260:Female; D011247:Pregnancy; D011555:Pseudopregnancy; D011817:Rabbits; D011960:Receptors, Estrogen / Q000032:analysis*; D011980:Receptors, Progesterone / Q000032:analysis*; D014018:Tissue Distribution
chemical_list: D011960:Receptors, Estrogen; D011980:Receptors, Progesterone