Endometrial content of nuclear estrogen receptor and receptivity for ovoimplantation in the rat.
The purpose of this study was to provide information concerning the amount of nuclear binding sites for estrogen in endometrial cells during the first week of pregnancy in the rat. The "insoluble" (high-salt non-extractable) binding during the first four days of pregnancy follows a circadian rhythm, with a maximal value at midnight, and a minimal one a noon. By day 5, the amount plateaus at a minimal value. The number of estradiol binding sites of the soluble (high-salt extractable) nuclear fraction shows a similar pattern. All the necessary elements for the estrogen-dependent induction of endometrial receptivity for nidation appear, therefore, to be present already by day 3, but the turning on of the endometrial response to estrogen on day 4 seems to depend on additional factor(s).
D000818:Animals; D002467:Cell Nucleus; D004247:DNA / Q000378:metabolism; D004717:Endometrium / Q000378:metabolism*; D004967:Estrogens / Q000378:metabolism*; D005260:Female; D011247:Pregnancy; D011270:Pregnancy, Animal; D051381:Rats; D011956:Receptors, Cell Surface; D013997:Time Factors
D004967:Estrogens; D011956:Receptors, Cell Surface; D004247:DNA