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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The distribution of estrogen and progesterone receptors (ER and PR, respectively) was studied immunohistochemically in the chick oviduct. Estrogen receptor immunoreactivity was found only in the nuclei of glandular epithelial cells. Progesterone receptor was found in the nuclei of glandular and luminal epithelia, stroma, smooth muscle cells and in the mesothelium. The dissimilar distribution of ER and PR suggests that either ER concentration in the luminal epithelium and smooth muscle is very low (below the sensitivity of ER immunostaining) or that estrogens control their PR synthesis indirectly via ER in glandular cells. A known estrogen-inducible protein, ovalbumin, was localized in the same glandular epithelial cells as ER. A progestin-inducible protein, avidin, was found in part of the luminal and glandular epithelium cells but not in other PR-positive cell types. This indicates the importance of cellular differentiation in the regulation of avidin synthesis. Estrogen and progesterone administration had effects also on ER and PR immunoreactivity. Estrogen and progesterone administrations for 24 h decreased markedly the immunoreactivity of their receptors. The decrease in receptor immunoreactivity is most likely due to a transient loss of immunoreactive receptor protein, since the antibodies (H222, PR6) react both with transformed (4 S) and non-transformed (8 S) receptor forms. At the subcellular level, PR was localized in the chromatin by immunoelectron microscopy. Progestin administration seemed to decrease PR immunoreactivity especially in the heterochromatin area, suggesting that conformational chromatin rearrangements occur during down-regulation of PR.
Mol Cell Endocrinol 1990 Mar 05
PMID:Distribution of estrogen and progesterone receptors and steroid-regulated gene products in the chick oviduct. 232 29

Estrogen induces DNA synthesis to a lesser degree, but with similar kinetics compared to insulin-like growth factors when added to quiescent MCF7 human breast cancer cells. Moreover, this steroid rapidly induces expression of the growth-related c-fos and c-myc protooncogenes. The induction was shown to be a direct effect, independent of protein synthesis. These results demonstrate that no growth factor production is involved in estrogen-induced protooncogene expression, and that these direct effects on gene expression may be an important step in estrogen-induced mitogenesis.
Mol Cell Endocrinol 1989 Jul
PMID:Direct effects of estrogen on c-fos and c-myc protooncogene expression and cellular proliferation in human breast cancer cells. 250 74

The present study examined 1) whether the estrogen-regulated destabilization of albumin mRNA occurs in the nuclear or extranuclear fraction of the liver cell, and 2) whether the selective posttranscriptional regulation of albumin mRNA stability might result from covalent changes introduced in the processing or polyadenylation of the primary transcript. The disappearance of albumin mRNA after estrogen is restricted to the extranuclear fraction of the cell. Transient changes in steady state levels of the mature nuclear transcript were observed that mirrored the transient estrogen-induced changes previously reported for albumin gene transcription. When assayed 24 h after estrogen (when albumin RNA is virtually undetectable in the extranuclear fraction) the steady state levels of both the primary and mature albumin transcripts found in the nucleus were the same as observed in control animals. Estrogen had no effect on the splicing or selection of polyadenylation sites on the 3'-UTR as determined by high resolution gel analysis of the 3'-UTR and DNA sequencing of cDNA clones isolated from a liver library from an estrogen-treated male Xenopus. Most eukaryotic mRNAs have poly(A) tracts several hundred residues in length, and recent studies have demonstrated that a change in the stability of a number of mRNAs correlates directly with the degree of polyadenylation. Albumin contrasts sharply with this, first because it has an exceptionally short poly(A) tail of 17 residues, and second because the degree of polyadenylation is totally unrelated to its destabilization in response to estrogen. These findings indicate that a unique pathway is involved in the regulation of albumin RNA stability by estrogen in Xenopus.
Mol Endocrinol 1989 May
PMID:Extranuclear estrogen-regulated destabilization of Xenopus laevis serum albumin mRNA. 254 54

Estrogen and progesterone or estrogen and glucocorticoid receptors functionally cooperate in gene activation if their cognate binding sites are close to one another. These interactions have been described as synergism of action of the steroid receptors. The mechanism by which synergism is achieved is not clear, although protein-protein interaction of the receptors is one of the favorite models. In transfection experiments with receptor expression vectors and a reporter gene containing estrogen and progesterone-glucocorticoid receptor binding sites, we have examined the effects that different portions of the various receptors have on synergism. N-terminal domains of the chicken progesterone and human glucocorticoid receptors, when deleted, abolished the synergistic action of these receptors with the estrogen receptor. Deletion of the carboxy-terminal amino acids 341 to 595 of the estrogen receptor produced a mutant receptor that could not trans-activate on its own. This mutant receptor did not affect the action of the glucocorticoid receptor but functioned synergistically with the progesterone receptor. We therefore conclude that the synergistic action of the receptors for estrogen and progesterone is mechanistically different from the synergistic action of the receptors for estrogen and glucocorticoid.
Mol Cell Biol 1989 Dec
PMID:Different regions of the estrogen receptor are required for synergistic action with the glucocorticoid and progesterone receptors. 258 23

Sex steroids are major regulators of PRL receptor expression in rat liver. Using a probe encoding the rat PRL receptor we have studied receptor mRNA levels in female rat liver during ontogeny and in response to estrogen treatment. Steady state mRNA levels were determined by Northern blot and densitometric analysis. Messenger RNA levels have been compared to the number of binding sites, which was assessed by Scatchard analysis of [125I]ovine PRL binding in membrane preparations. Our results show that steady state mRNA and binding levels of PRL receptors are both regulated by development and estrogens, but that binding does not exactly parallel mRNA levels. From the developmental stages of prepuberty to adult, receptor numbers increase 8-fold, whereas mRNA levels increase 3-fold. Estrogen treatment stimulates receptor levels 6-fold, but mRNA levels are only increased 3-fold. These results suggest that PRL receptor gene expression in rat liver is regulated at the transcriptional or posttranscriptional level as well as at the translational level.
Mol Endocrinol 1989 Jun
PMID:Multiple regulation of prolactin receptor gene expression in rat liver. 273 54

alpha 1-Adrenergic and muscarinic cholinergic stimuli activate uterine contraction. Estrogen increases adrenergic but not cholinergic sensitivity of rabbit myometrium independent of its effects on adrenoceptor concentration. Since both alpha 1-adrenergic and muscarinic receptors are coupled to phosphatidylinositol hydrolysis, we tested the hypothesis that estrogen increases adrenergic- but not cholinergic-mediated inositol triphosphate production. We found that maximal production of inositol phosphates stimulated by norepinephrine was increased approximately 3-fold following estrogen treatment. Cholinergic-stimulated production was not increased by estrogen treatment. These results demonstrate that the effect of estrogen to enhance uterine adrenergic sensitivity is associated with an increased post-receptor response. The nature of the selectivity of estrogen for adrenergic versus cholinergic response remains obscure, but the results suggest the presence of parallel pathways for receptor activation of a common post-receptor response.
Mol Pharmacol 1987 Nov
PMID:Estrogen increases adrenergic- but not cholinergic-mediated production of inositol phosphates in rabbit uterus. 282 81

We studied the action of E-diethylstilbestrol (E-DES), erythro-hexestrol (erythro-HES), and E,E-dienestrol (E,E-DIES) on microtubule formation. The three drugs inhibit this formation from microtubular protein; the percentages of inhibition were, respectively, 15% and 45% for 1.25 X 10-s M E-DES and E,E-DIES. With purified tubulin 6S, 7.5 X 10(-6) M E,E-DIES and erythro-HES induced a 20% inhibition. In the case of E-DES, our results are in good agreement with previous ones. These drugs partially disrupt preformed microtubules. Moreover, when E,E-DIES (5 X 10(-5) M) is added to tubulin, loosely organized aggregates composed of twisted ribbon structure are formed. In the case of erythro-HES, similar structures were observed but at higher concentrations. With E-DES, no organized structures are present.
Mol Pharmacol 1987 Dec
PMID:Interaction of some estrogenic drugs with tubulin. Formation of twisted ribbon structures. 282 88

C6 Rat glioma cells acquire an astrocyte-like morphology (cytoplasmic shrinking) after exposure to beta-adrenergic compounds (e.g., isoproterenol) in serum-free medium. This morphological response is mediated by elevation of the intracellular cAMP level and possibly by activation of a kinase phosphorylating and inactivating the myosin-L-kinase in analogy to observations with smooth muscle cells. The result is a disturbance of the stress fiber function, which depends on a cooperation between actin and myosin. Diethylstilbestrol (DES) induces an identical morphological response in these cells under serum-free conditions. However, under the influence of DES no increase of the cAMP level was observed. In addition, at concentrations not inducing these morphological responses, DES inhibits the isoproterenol-induced effect when administered simultaneously or prior to the beta-receptor agonist. DES does not inhibit the isoproterenol-mediated morphological response when added after isoproterenol treatment. Furthermore, if serum is added to cells showing the isoproterenol- or DES-mediated astrocyte-like morphology (DES or isoproterenol present all the time) the cells regain their normal fibroblast-like morphology within 30 min. In view of these results the question arises whether DES interferes with myosin-L-chain phosphorylation or whether it directly interacts with the cytoskeleton stress fiber components, as cytochalasin B1 does. Thus it remains to be established whether the observed effects are related to the estrogenic activity of DES. Similar effects were observed with Syrian hamster embryo fibroblasts under the influence of DES and the naturally occurring steroid estrogen 17-beta-estradiol.
Mol Toxicol
PMID:Does diethylstilbestrol (DES) change the stress fiber organization in C6 rat glioma cells? 285 47

Two estrogen sulfatases, arylsulfatase C-estrone sulfatase (ASC-ES) and d-equilenin sulfatase (EqS) were demonstrated histochemically in the normal human female breast, in benign breast diseases and in infiltrating mammary ductal carcinomas to study their significance in the pathogenesis of epithelial proliferations. By hydrolyzing estrone sulfate, the amount of which in female blood is about ten times greater than that of estradiol or estrone, estrogen sulfatases can produce a high local concentration of estrogens. A simultaneous azo-coupling method for histochemical demonstration of ASC-ES is described in the present study; EqS was demonstrated by a previously described method. Estrogen sulfatases were not found in the normal female breast. Both estrogen sulfatases were found in epithelial cells in some examples of mastopathic disease and in fibroadenomas, while ASC-ES was found in periductal fibroblasts. In some cases of infiltrating ductal carcinomas, estrogen sulfatases were present in carcinoma cells. In most of these tumors ASC-ES activity was observed in fibroblasts around infiltrative cell cords. There was no correlation between the presence of estrogen sulfatases and of hormone receptors in carcinomas. It is concluded that estrogen sulfatases play no role in the early stages of benign or malignant epithelial proliferations. However, the induction of estrogen sulfatases may promote epithelial proliferation in some cases if estrogen receptors are present in epithelial cells.
Virchows Arch B Cell Pathol Incl Mol Pathol 1985
PMID:Histochemistry of estrogen sulfatases in human breast diseases. 286 35

Light microscopy was used to examine the oviduct and endometrium of offspring from mice administered DES (10 micrograms/kg in 0.1 cc of corn oil, subcutaneously) or corn oil alone on Day 15 of gestation. Offspring were sacrificed at 5, 7 and 9 months of age. Oviduct changes in DES exposed offspring included numerous abnormal secretory cells which lined the mucosal folds of the isthmus. These cells contained a distinct granular cytoplasm which was eosinophilic and a nucleus displaced towards the apical surface. In addition both the ampulla and isthmus had mucosal folds which extended to the serosal surface and an accumulation of subepithelial fibrinoid material. Endometrial changes included squamous metaplasia of both the surface and glandular epithelial layer as well as extensive cystic glandular hyperplasia. In addition the endometrial connective tissue stroma exhibited fibrinoid accumulation. These changes may reflect an altered endocrine environment resulting from ovarian abnormalities during adulthood.
Virchows Arch B Cell Pathol Incl Mol Pathol 1985
PMID:Histology of the adult mouse oviduct and endometrium following a single prenatal exposure to diethylstilbestrol. 286 44


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