Immuno-biochemical assay for determination of nuclear steroid receptors during tamoxifen therapy.
The exact knowledge of hormone receptor status is critical for therapeutic strategies in hormone-dependent tumors. The influence of tamoxifen on estrogen receptor concentration has to be taken into account when evaluating results in tamoxifen-treated patients. We studied the receptor modulation of tumors xenotransplanted into nude mice (one breast and one endometrial carcinoma) after injection of 50 micrograms tamoxifen/mouse. To differentiate between unoccupied and occupied receptors, determinations were done by an enzyme immunoassay for the estrogen receptor under low- and high-salt extraction. With low-salt extraction we found a temporary decrease of the estrogen receptor concentration within the first hours after tamoxifen treatment. This decrease lasted for several days before recovery to pretreatment levels occurred. The hormone-receptor complexes, tightly bound to acceptor sites of the DNA, increased more than 15 times within 24 h. These values remained at increased levels for 2-7 days, after which a decrease to initial level was observed.
Vering
A
A
Department of Gynecology, University Medical Center, Frankfurt am Main, Germany.
Vockel
A
A
Stegmüller
M
M
Bender
H G
HG
D000818:Animals; D001943:Breast Neoplasms / Q000737:chemistry* / Q000188:drug therapy; D002467:Cell Nucleus / Q000737:chemistry*; D016889:Endometrial Neoplasms / Q000737:chemistry* / Q000188:drug therapy; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D011960:Receptors, Estrogen / Q000032:analysis / Q000187:drug effects* / Q000276:immunology; D011980:Receptors, Progesterone / Q000032:analysis / Q000187:drug effects* / Q000276:immunology; D013629:Tamoxifen / Q000494:pharmacology / Q000627:therapeutic use*; D014183:Transplantation, Heterologous
D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D013629:Tamoxifen