Klinge CM, Knox DT, Bambara RA, Zain S, Hilf R. Antiestrogen(4-hydroxytamoxifen)-charged estrogen receptor binding to nuclei from normal and neoplastic rat mammary tissues is not affected by host hormonal status.
JOURNAL OF STEROID BIOCHEMISTRY 1989;
33:335-40. [PMID:
2779224 DOI:
10.1016/0022-4731(89)90321-x]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Interaction of [3H]4-hydroxytamoxifen-charged estrogen receptor [( 3H]AER) with nuclei was compared to that of [3H]17 beta-estradiol-charged estrogen receptor [( 3H]ER) in vitro. Specificity of [3H]AER binding was demonstrated since more than 90% of [3H]AER binding was displaced by ten-fold excess estradiol-charged ER. For R3230AC tumors, the number of [3H]AER binding sites was approximately 40% lower than the number of [3H]ER binding sites. There were no differences in affinity of binding of these receptors complexes (Kd range 0.7-1.6 nM). In contrast 0.7-1.6 nM). In contrast to a reduction of [3H]ER binding after ovariectomy, no difference in the number of [3H]AER binding sites was seen among tumors from intact, ovex, or estrogen-treated ovex rats. These results suggest that [3H]AER bind to 60% of the sites that bind [3H]ER, and that neither tissue type nor host ovarian status affects the number of nuclear [3H]AER binding sites.
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