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Query: UMLS:C0009443 (cold)
 92,137 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The authors prepared the prolactin marker with iodine-125 and made iodine-125-human prolactin and iodine-125-sheep prolactin. To make the complex, iodine-125-human prolactin was incubated with prolactin receptors isolated from female rat liver cell membranes. This complex is reversible and can be replaced by cold human prolactin. Studies with mammary glands of various animals have indicated that the prolactin receptor seemed to be a peptide or a protein of macromolecules in chemical nature. Estrogen enhanced the binding ability of iodine-125-sheep prolactin to prolactin receptor of rat liver cell membranes. The mammary cells from hyposectomized animals lost the binding ability, and this ability was not recovered even by estrogen administration. In experimental animals, the growth of mammary cancer, induced by dimethyl benzanthracene, was enhanced by the administration of prolactin and reduced by the introduction of an antiprolactin serum. Ergocornine which would suppress the secretion of prolactin also reduced the cancer growth. The factors which would increase the secretion of prolactin increased the tumor growth. Mammary cancer cells have generally less binding ability to prolactin than the normal mammary cells. These cancer cells in animals seem not to be prolactin dependent and have an autonomic nature. The relationship between prolactin and human mammary cancer is not yet entirely clear. However, there is a possibility that prolactin may play a role in certain mammary cancer. Reports on prolactin receptor in human mammary cancer cells are sparse. Although the authors found estrogen receptor in some mammary cancer cases, they were not able to find a significant amount of prolactin binding ability in these cells.
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PMID:[Radioreceptor assay of prolactin]. 0 10

Norethindrone (ENT), which is a representative in estrane series of progestogen, is not only strongly progestational but also estrogenic and in some cases, antiestrogenic. To understand progestational effect and antiestrogenic effect, the interactions of ENT on estrogen and progestogen receptors were studied in the uterine cytosol of white female rabbit. The 274,200 X G supernatant of uterine homogenate was used as cytosol. 3H-Estradiol, 3H-Progesterone, 3H-ENT or cold ENT were incubated with uterine cytosol at 4 degrees C for 2 hours. Results are as follows: 1. Sucrose gradient centrifugation [5 approximately 20% linear and 40,000 rpm (159,200 X G) for 16 hours at 4 degrees C]: ENT was bound to extrogen 8S receptor in immature rabbit uterus (Fig. 2 & 3), and to progestogen 8S receptor in estrogen primed rabbit uterus (Fig. 5). 2. Kinetic study, determined by dextran coated charcoal (0.001% dextran and 0.1% charcoal): (1) In the uterine cytosol of immature rabbit, 3H-estradiol-receptor binding was observed with Kd divide by 3.6 X 10-9 M and it was revealed that ENT was a competitive inhibitor to this binding with Ki divide by 2.6 X 10-6 M, as in Fig. 6. (2) 8S component, obtained by centrifugation of uterine cytosol (Fig. 1) in estrogen primed rabbit, binds 3H-progesterone with Kd divide by 8.1 X 10-10 M and Bm (maximal binding sites) divide by 5.0 X 10-8 M/mg of protein, and ENT was a competitive inhibitor in this binding with Ki divide by 2.3 X 10-9 M (FIG. 7 & 8). 3H-ENT-8S binding was demonstrated with Kd divide by 1.1 X 10-9 M and Bm divide by 8.7 X 10-8 M/mg of cytosol protein (Fig. 8). These results indicate: (a) ENT is bound to both estrogen and progestogen receptors in 8S macromolecules of uterine cytosol, (b) competitive inhibition of ENT to these bindings indicated that ENT is bound to these receptors at the steroid binding sites where estradiol and progesterone bind to, (c) ENT has much more affinity to progestogen receptor (Ki divide by 2.3 X 10-9 M) than to estrogen receptor (Ki divide 2.6 X 10-6 M), (d) while ENT is bound to progestogen and estrogen receptors at the same time, Bm of ENT (8.7 X 10-8 M/mg of cytosol protein) is more than Bm of progesterone (5.0 X 10-9 M/mg of cytosol protein), and Kd of ENT (1.1 X 10-9 M) was less than Ki of ENT (2.3 X 10-9 M) in the binding to progesterone-receptor. Biologically, while ENT is bound to progestogen -receptor with high affinity and to estrogen receptor with low affinity, ENT is actually progestational in low dose and antiestrogenic in high dose but the anti-estrogenicity seems to be incomplete in vivo as ENT may be metabolized to a potent estrogenic compound, ethinyl estradiol
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PMID:[Interaction of norethindrone on estrogen and progesterone receptors in the rabbit uterine cytosol (author's transl)]. 18 90

In order to analyse the molecular weight polymorphism of the estrogen receptor (ER) in MCF-7 cells, we have developed a procedure which allowed in situ linkage of ER by (3H) tamoxifen aziridine and provided labelled proteins in conditions which minimized protease activities. After labelling, cell lysis was performed in SDS buffer containing various concentrations of [symbol: see text]-mercaptoethanol. Proteins extracted with phenolic solution and precipitated by cold acetone were analysed by SDS PAGE. It appears that beside the form of 67 kDa already described, binding entities of tamoxifen aziridine were also present at a molecular mass of 110 kDa and 45 kDa. On the other hand, investigations on the effect of 12-0-Tetradecanoyl Phorbol 13-Acetate (TPA) showed that TPA induces a decrease of the 67 kDa entity.
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PMID:Modulation of the estrogen receptor structure, evidence of a heterogeneity. 226 30

Treatment of human breast cancer cytosol with tamoxifen (Tam) or 4-monohydroxytamoxifen (MHT) enhances the immunoreactivity of the estrogen receptor toward monoclonal antibody H222 but not monoclonal antibodies D547 or D75. This effect is evident from an increase in the apparent receptor content measured by the Abbott enzyme immunoassay, which uses peroxidase-labeled H222 as the chromogenic marker, and in the rate and size of the sedimentation peak of the immune complex of the receptor with radiolabeled H222. In contrast, MHT shows no effect in reversed immunoassay systems that use peroxidase-labeled D547 or D75 as chromogenic markers, nor does it affect the sedimentation peak of the complex of D547 with the receptor. MHT can exert its action on receptor bound to immobilized antibody. These results indicate that reaction with antiestrogens causes a change, probably conformational, in the receptor protein that exposes an occult antigenic determinant recognized uniquely by H222. Since this can occur in cytosol previously treated with excess estradiol in the cold, it appears to result from an interaction of antiestrogens with a region of the receptor distinct from the estrogen-binding site, suggesting that agonist and antagonist actions may involve different parts of the receptor molecule.
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PMID:Binding of antiestrogens exposes an occult antigenic determinant in the human estrogen receptor. 245 27

A peroxidase-antiperoxidase technique was used to visualize estrogen and progesterone receptors in stored imprints and cryostat sections of breast carcinomas that were prepared at the time of biopsy or frozen section diagnosis. This was done to provide an alternate technique for the assessment of the receptor status of tumors that could not be adequately assayed with other biochemical or immunocytological methods. Fixation in Zamboni's fixative followed by passage through cold methanol and acetone before storage at -80 C insured good preservation of the receptor proteins over extended periods of time (up to 56 weeks). Immunostaining of these stored preparations with monoclonal antibodies against estrogen receptor (H222) and progesterone receptor (JZB39 and KD68) showed a high degree of correspondence with immunocytochemical assays (ER-ICA and PR-ICA) and biochemical analysis. This technique is easy to perform and provides reliable information, even in tumors that are too small and/or ill defined to permit separate sampling for receptor assays.
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PMID:Immunohistochemical assessment of estrogen and progesterone receptors in stored imprints and cryostat sections of breast carcinomas. 254 46

Cancer of the breast is the most common tumor in females in Singapore, with the rate of 20.7 per 100,000 per year (1977 estimate), which is predicted to increase to 29.8 per 100,000 women per year by 1995. A detailed histopathologic review of 50 primary breast cancer tumors analyzed for estrogen receptor (ER) level was carried out and a variety of morphologic features correlated with ER results to identify any factors that will improve the management and prognosis for breast cancer. Cytosol was incubated with 3H-estradiol in the presence and absence of cold diethylstilbestrol, and bound and free hormone were separated by Dextran-coated charcoal method. Tumors binding more than 5 fmol/mg cytosol protein were classified as ER-positive. Progesterone receptor (PR) level was analyzed in some specimens with the use of a similar method. Most of the patients were Chinese (90%). Three patients were Malays, one was Indian, and one was European in this series. Results indicated that there was strong correlation between ER level, age, and histologic grade of the tumors. No correlation existed between absence or presence of lymph node metastases and ER. Although there was a trend for ER-positive tumors to have a low-grade lymphocytic infiltration, the difference was not statistically significant.
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PMID:Correlation of steroid receptors with histologic differentiation in mammary carcinoma. A Singapore experience. 299 51

We have isolated and sequenced a cDNA clone encompassing the entire protein coding region of the Xenopus laevis estrogen receptor (xER). The Xenopus ER, the first steroid hormone receptor to be sequenced from a cold-blooded organism, exhibits two regions of striking amino acid homology with the human and avian ERs. In the putative DNA binding region, the amino acid sequence of the xER differs from those of the human and avian ERs at only one of 83 amino acids. The putative hormone binding region contains 44 and 46 amino acid blocks in which the sequence is identical in the Xenopus and human ERs. Blot hybridizations of Xenopus liver RNA suggest that the xER is encoded by four mRNAs with lengths of approximately 9, 6.5, 2.8, and 2.5 kilobases. In contrast, hybridization of human RNA to a human ER cDNA clone reveals only a single major ER RNA, approximately 6.7 kilobases in length.
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PMID:The Xenopus laevis estrogen receptor: sequence homology with human and avian receptors and identification of multiple estrogen receptor messenger ribonucleic acids. 327 94

Radiohalogenated estrogens have considerable potential for estrogen receptor-directed imaging and therapy for cancers which contain such receptors. In an effort to evaluate the potential of the triphenyl ethylene structure for such purposes we have synthesized 3 series of 2-halosubstituted triphenylethylenes containing oxygen functions in the 4 position of both aromatic rings attached to carbon 1 of the ethylene and tested their uterotrophic activity and competition for rat uterine low salt extractable, "cytosol" estrogen receptor. Most active, both as competitors for estradiol binding to estrogen receptors and by their ability to stimulate uterine growth are the 1,1-bis-4-hydroxyphenyl derivatives although the 1,1-bis-4-acetoxyphenyl derivatives also show good receptor affinity and demonstrate uterotrophic activities. However, since uterine cytosol contains enzymes which hydrolyze the acetates to the free phenols even during the incubation in the cold used for the competitive binding studies, a significant portion of the competition shown by the diacetates is probably due to their hydrolysis products, the free phenols. The 1,1-bis-4-methoxyphenyl derivatives are weak competitive binders and demonstrate uterotrophic activity only when administered at the higher, 20 micrograms, doses. Comparing the relative activities of various halogens at the 2 position, in each series the bromo and chloro derivatives generally were of similar activity and significantly more active than the corresponding iodo derivative. The non-halogen substituted derivatives were very good competitors for estrogen receptor binding but less active with regard to uterine growth stimulation, providing evidence that in vivo the vinyl halides would appear to be relatively stable to simple dehalogenation. Since they show reasonably good apparent affinities for the estrogen receptor and apparent in vivo stability, reflected by estrogenic activity, these halogen substituted triphenylethylene derivatives appear to be promising substrates for investigations of estrogen receptor directed imaging and therapy.
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PMID:Estrogen receptor binding affinity and uterotrophic activity of triphenylhaloethylenes. 338 26

Experimental conditions affecting the partitioning of the estrogen receptor were studied. Homogenization of rat uteri at 25 degrees C resulted in a particulate partitioning of the estrogen receptor. The use of frozen tissue (-70 degrees C) or pre-exposure of the tissue to 0 degrees C prior to 25 degrees C homogenization, homogenization at 0 degrees C and tissue dilution all induced soluble partitioning of the receptor. The estrogen receptor found in the particulate fraction was mostly associated with the nuclei, even in the absence of hormone. The interaction between estradiol and the estrogen receptor induced modification in the receptor's charge and size that promoted its cold-insensitive association with the nuclei of target cells. These modifications were studied in a cell-free in vitro system and were reversibly blocked by molybdate. Similar changes occurred in vivo when estradiol interacted with the receptor in the nuclei of target cells.
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PMID:Interaction between estrogen receptor and subcellular structures of target cells: nuclear localization of unoccupied receptor and its modification induced by estradiol. 352 48

Homogenization of rat uteri at 25 degrees C resulted in a particulate partitioning of the estrogen receptor. Homogenization at 0 degrees C, the use of frozen tissue, or the pre-exposure of the tissue to 0 degrees C prior to 25 degrees C homogenization induced soluble partitioning of the estrogen receptor. Binding of a radiolabeled monoclonal antibody indicated that, in absence of estradiol, the estrogen receptor is particulate and is associated with the nuclei-enriched fraction of the target cell. The presence of receptor in the soluble fraction thus appears to be an artifact of homogenization. The unoccupied receptor, loosely associated with the particulate fraction (cold-sensitive) represents the "native" form of receptor which, upon arrival of the hormone, becomes tightly associated (cold-insensitive). The transition from the cold-sensitive to the cold-insensitive status is accompanied by a modification of the electrical charge of the receptor.
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PMID:Particulate nature of the unoccupied uterine estrogen receptor. 399 17


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