title: Local effect of the blastocyst on estrogen and progesterone receptors in the rat endometrium.
abstract: Nuclear receptors for both estradiol and progesterone were present in twofold higher concentrations in implantation sites than in nonimplantation regions of the endometrium of 6-day pregnant rats. Decidualization in the absence of an embryo was not accompanied by a similar increase in the concentration of nuclear receptors. Moreover, this difference in receptor distribution between the implantation and nonimplantation areas persisted when a major part of the maternal supply of sex steroids was suppressed by ovariectomy on day 5 of pregnancy. These results support the hypothesis that steroids originating from the embryo affect the endometrial implantation site.
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000378:metabolism*; D002369:Castration; D002467:Cell Nucleus / Q000378:metabolism; D003656:Decidua / Q000378:metabolism; D004717:Endometrium / Q000378:metabolism* / Q000648:ultrastructure; D005260:Female; D005865:Gestational Age; D011247:Pregnancy; D011555:Pseudopregnancy; D051381:Rats; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*
chemical_list: D011960:Receptors, Estrogen; D011980:Receptors, Progesterone