Chilton B S, Nicosia S V, Lyttle C R
J Steroid Biochem. 1982 Oct;17(4):363-9. doi: 10.1016/0022-4731(82)90627-6.
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.
