Steroid Hormone Receptors in the Rat Mammary Adenocarcinoma Induced by N-Hydroxy-N-2-fluorenylacetamide

The steroid hormone receptors in N-2-fluorenylacetamide (2-FAA)- and N-hydroxy-2-FAA-induced mammary adenocarcinomas in outbred Sprague-Dawley rats were analyzed. Both 8S and 4S estrogen-binding components have been detected in cytosols of these tumors following sucrose gradient sedimentation in low...

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Bibliographic Details
Published in:JNCI : Journal of the National Cancer Institute 1982-07, Vol.69 (1), p.41-45
Main Authors: Li, Sara Antonia, Malejka-Giganti, Danuta, Li, Jonathan J.
Format: Article
Language:English
Subjects:
2-Acetylaminofluorene - analogs & derivatives
2-Acetylaminofluorene - pharmacology
Adenocarcinoma - metabolism
Animals
Breast Neoplasms - metabolism
Castration
Centrifugation, Density Gradient
Estrogens - metabolism
Female
Hydroxyacetylaminofluorene - pharmacology
Mammary Glands, Animal - analysis
Rats
Rats, Inbred Strains
Receptors, Cell Surface - biosynthesis
Receptors, Progesterone - biosynthesis
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Summary:The steroid hormone receptors in N-2-fluorenylacetamide (2-FAA)- and N-hydroxy-2-FAA-induced mammary adenocarcinomas in outbred Sprague-Dawley rats were analyzed. Both 8S and 4S estrogen-binding components have been detected in cytosols of these tumors following sucrose gradient sedimentation in low salt. Competitive binding analyses of this binder indicated a specificity profile expected of an estrogen receptor. Both androgen and progesterone receptors were also present in the cytosols of these mammary tumors. While the androgen receptor sedimented in the 8S region of the gradient, the progestin binder appeared only as a 4S moiety under similar conditions. The relative concentrations of these receptors (expressed in fmol/mg protein ± SE) were: 17β-estradiol (28.6± 4.1) > 5α-dihydrotestosterone(8.5± 2.2)> progesterone (5.0± 1.3). The progesterone receptor was increased at least eightfold in the mammary adenocarcinomas from ovariectomized rats that were treated with diethylstilbestrol for 6 days. Binding equilibrium data indicated Ka = 1.2–1.8×109 M−1 for the above cytoplasmic hormone receptor complexes (Ka, association constant). Although cytosols prepared from lactating mammary gland contained appreciable quantities of gluco-corticoid receptor, only trace amounts were found in the mammary adenocarcinoma.
ISSN:0027-8874
1460-2105
DOI:10.1093/jnci/69.1.41