The biological significance of estradiol receptor binding to DNA.
MTW9-D, a rat mammary tumor derived from MTW9 by chronic administration of the dopamine antagonist drug R33,812 shows ovariectomy-induced regression (OIR). MTW9-MtT is also a variant of MTW9, grown by coimplantation of a mammosomatotropic tumor MtTW10, but it does not show OIR. However, when the mammosomatotropic tumor (MtT) is resected, the tumor regresses and shows rapid OIR; implantation of MtT into animals bearing MTW9-D prevents OIR following drug withdrawal. The estradiol receptor (ER) from MTW9-D cytosol binds to DNA-cellulose significantly more than that from MTW9-MtT. After MtT resection, the mammary tumor ER binds to DNA-cellulose, as well as ER from MTW9-D, whereas implantation of MtT into animals bearing MTW9-D decreases ER binding to DNA-cellulose. The significance of these findings in relation to possible clinical application is discussed.
D000818:Animals; D002369:Castration; D004247:DNA / Q000378:metabolism*; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D066298:In Vitro Techniques; D008325:Mammary Neoplasms, Experimental / Q000378:metabolism* / Q000628:therapy; D009374:Neoplasms, Experimental / Q000378:metabolism; D009376:Neoplasms, Hormone-Dependent / Q000378:metabolism*; D011388:Prolactin / Q000378:metabolism / Q000502:physiology; D051381:Rats; D011920:Rats, Inbred WF; D011960:Receptors, Estrogen / Q000378:metabolism*
D011960:Receptors, Estrogen; D004958:Estradiol; D011388:Prolactin; D004247:DNA