Heterogeneity of Nuclear Estrogen-Binding Sites in the Rat Uterus: A Simple Method for the Quantitation of Type I and Type II Sites by [3H]Estradiol Exchange*

Endocrinology ◽  
1981 ◽  
Vol 109 (1) ◽  
pp. 62-69 ◽  
Author(s):  
BARRY M. MARKAVERICH ◽  
MARILYN WILLIAMS ◽  
SUSAN UPCHURCH ◽  
JAMES H. CLARK
1988 ◽  
Vol 34 (10) ◽  
pp. 2053-2057 ◽  
Author(s):  
S Raam ◽  
D M Vrabel

Abstract We present evidence to show that monoclonal antibodies to estrogen receptors (ER) in solid phase recognize the secondary estrogen binding sites with moderate to low affinity for estradiol (E2). An excellent quantitative agreement was found in five cytosols between the ER values obtained by the enzyme immunoassay (ER-EIA) and the amount of secondary estrogen binding sites measured by the assay involving dextran-coated charcoal (Clin Chem 1986;32:1496). The immunoreactive protein recognized by the antibody-coated beads, when allowed to react with ER(+) cytosols, is shown to bind [3H]estradiol only when the ligand concentration exceeds 8 nmol/L. Further biochemical and functional characterization of the immunoreactive protein is required to establish similarities/dissimilarities between this protein, high-affinity Type I ER sites, and the secondary sites such as Type II sites.


1987 ◽  
Vol 7 (10) ◽  
pp. 3538-3547 ◽  
Author(s):  
R J Haché ◽  
S P Tam ◽  
A Cochrane ◽  
M Nesheim ◽  
R G Deeley

The stimulation of chicks or embryos with estrogen results in transient, hepatic expression of the vitellogenin gene, as well as long-term, propagatable alterations in the rapidity with which the gene can be reactivated. We examined the possibility that nuclear, type II estrogen-binding sites are involved in this long-term change in response characteristics. We demonstrate that the primary induction kinetics of type II sites in embryos and chicks correlated with the expression of the vitellogenin gene and that once their induction was triggered by estrogen, they accumulated, were propagated, and persisted for months after withdrawal of the hormone. We also show that their accumulation in the embryo was accompanied by prolonged expression of both the vitellogenin and very low-density apolipoprotein II genes, in the absence of elevated levels of type I receptor, and that the type II sites, like the classical receptor, appear to be preferentially associated with active or potentially active chromatin. Finally, we describe a regulatory mechanism, tested by computer modelling, that simulated the behavioral characteristics of these nuclear estrogen-binding sites and which may explain their role in mediating the long-term effects of estrogen.


1987 ◽  
Vol 7 (10) ◽  
pp. 3538-3547
Author(s):  
R J Haché ◽  
S P Tam ◽  
A Cochrane ◽  
M Nesheim ◽  
R G Deeley

The stimulation of chicks or embryos with estrogen results in transient, hepatic expression of the vitellogenin gene, as well as long-term, propagatable alterations in the rapidity with which the gene can be reactivated. We examined the possibility that nuclear, type II estrogen-binding sites are involved in this long-term change in response characteristics. We demonstrate that the primary induction kinetics of type II sites in embryos and chicks correlated with the expression of the vitellogenin gene and that once their induction was triggered by estrogen, they accumulated, were propagated, and persisted for months after withdrawal of the hormone. We also show that their accumulation in the embryo was accompanied by prolonged expression of both the vitellogenin and very low-density apolipoprotein II genes, in the absence of elevated levels of type I receptor, and that the type II sites, like the classical receptor, appear to be preferentially associated with active or potentially active chromatin. Finally, we describe a regulatory mechanism, tested by computer modelling, that simulated the behavioral characteristics of these nuclear estrogen-binding sites and which may explain their role in mediating the long-term effects of estrogen.


1984 ◽  
Vol 259 (5) ◽  
pp. 2697-2700
Author(s):  
C R Lyttle ◽  
K L Medlock ◽  
D M Sheehan

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Seiya Watanabe ◽  
Yohsuke Murase ◽  
Yasunori Watanabe ◽  
Yasuhiro Sakurai ◽  
Kunihiko Tajima

AbstractAconitase superfamily members catalyze the homologous isomerization of specific substrates by sequential dehydration and hydration and contain a [4Fe-4S] cluster. However, monomeric and heterodimeric types of function unknown aconitase X (AcnX) have recently been characterized as a cis-3-hydroxy-L-proline dehydratase (AcnXType-I) and mevalonate 5-phosphate dehydratase (AcnXType-II), respectively. We herein elucidated the crystal structures of AcnXType-I from Agrobacterium tumefaciens (AtAcnX) and AcnXType-II from Thermococcus kodakarensis (TkAcnX) without a ligand and in complex with substrates. AtAcnX and TkAcnX contained the [2Fe-2S] and [3Fe-4S] clusters, respectively, conforming to UV and EPR spectroscopy analyses. The binding sites of the [Fe-S] cluster and substrate were clearlydifferent from those that were completely conserved in other aconitase enzymes; however, theoverall structural frameworks and locations of active sites were partially similar to each other.These results provide novel insights into the evolutionary scenario of the aconitase superfamilybased on the recruitment hypothesis.


1988 ◽  
Vol 255 (4) ◽  
pp. F736-F748 ◽  
Author(s):  
R. L. Duncan ◽  
W. M. Grogan ◽  
L. B. Kramer ◽  
C. O. Watlington

This study tests the hypothesis, in A6 epithelia, that 1) corticosterone stimulates active Na+ transport (short-circuit current, Isc) by an additional receptor mechanism to the type I (mineralocorticoid) and type II (glucocorticoid) mechanisms shared with aldosterone (Aldo) and 2) that the agonist may be 6 beta-OH-corticosterone made in the effector cell. The dose-response relationship of corticosterone at 24 h resolves into two components, by curve fitting, with a 50% effective concentration (EC50) for 10% of maximum Isc stimulation of 2 X 10(-9) M and an EC50 for the other 90% of 3 X 10(-7) M. The EC50 of the smaller component correlates with the apparent dissociation constant (K'd) of corticosterone for high affinity (type II) nuclear binding sites shared with Aldo. In unlabeled analogue competition studies Aldo and corticosterone displaced nuclear binding equally below 10(-8) M [3H]corticosterone, indicating only shared sites. However, nonshared saturable sites (displaced by corticosterone but not by Aldo) were found at [3H]-corticosterone concentrations above 10(-8) M. Concentration-binding curves performed with [3H]corticosterone, in presence of 1,000 X Aldo to displace shared sites, revealed a single class of binding sites with a half-maximal saturation of 2 X 10(-7) M, which is quite similar to the EC50 of the lower affinity component of Isc stimulation by corticosterone at 24 h. Reversed phase high-pressure liquid chromatography of nuclear extracts indicates that the saturable component of bound [3H] was 6 beta-OH-[3H]corticosterone derived from [3H]corticosterone. Thus, A6 cells metabolize corticosterone to 6 beta-OH-corticosterone, which in turn occupies lower-affinity receptors not shared with Aldo or corticosterone, to mediate most of the active Na+ transport stimulation by corticosterone.


1989 ◽  
Vol 257 (1) ◽  
pp. R87-R95 ◽  
Author(s):  
A. Gnionsahe ◽  
M. Claire ◽  
N. Koechlin ◽  
J. P. Bonvalet ◽  
N. Farman

Distal segment of several amphibians exhibits aldosterone-modulated ion transport properties. On the other hand, A6 cells, derived from Xenopus laevis (XL) kidney, are aldosterone sensitive. We examined the distribution of aldosterone binding sites in isolated tubules of XL compared with rabbit. After incubation with 2 nM [3H]aldosterone, microdissected tubular segments from proximal (PT), distal straight segment (DST), and flask cell collecting (CT) tubules from XL and from rabbit cortical thick ascending limb (CTAL), connecting (CNT), and collecting (CCD) tubules were processed for dry film autoradiography. In XL, specific nuclear labeling of type I (mineralocorticoid) sites was restricted to DST. Labeling of type II (glucocorticoid) sites was present all along the tubule. No specific cytoplasmic labeling was observed, except for type II sites in PT. In the rabbit, aldosterone binds to both type I and type II sites in the three tubular segments studied. In these segments, the binding was about fourfold higher than in DST of XL. These results bring direct evidence in designating the distal tubule of amphibians as a target epithelium for aldosterone. In addition, they suggest that A6 cell line may derive from DST of the Xenopus nephron.


2011 ◽  
Vol 25 (6) ◽  
pp. e217-e220 ◽  
Author(s):  
Wan-Fu Su ◽  
Shao-Cheng Liu ◽  
Feng-Shiang Chiu ◽  
Chia-Hsuan Lee

Background Vidian neurectomy was an option for treating allergic rhinitis in the past but outcomes varied. A modified transsphenoidal approach is proposed to simplify endoscopic vidian neurectomy. The postoperative evaluation of rhinorrhea, sneezing, and recurrence was investigated. Methods A total of 317 patients with refractory allergic rhinitis underwent 414 transsphenoidal vidian neurectomies from September 2006 to December 2010. A rigid nasal endoscope was used through a transsphenoidal approach to reach the vidian canal inside the sphenoid sinus (type I) or through its anterior opening into the pterygopalatine fossa (type II) and to cut or cauterize the vidian nerve. The surgical outcomes were analyzed for patients with at least 6 months of follow-up. Results Our approach was successful in 90.3% of the 414 vidian neurectomies. Vidian neurectomy was successful via the type I approach in 27 sides and type II approach in 347 sides. The short-term surgical outcomes of 163 patients who underwent a total of 236 vidian neurectomies with at least 6 months of follow-up were analyzed. Immediate, complete cessation of sneezing and rhinorrhea occurred uniformly. Three recurrences were detected during the 1–2 years of follow-up. The symptom of dry eye was reported for 172 surgical sides, but only 6 had persistent symptoms for > 6 months. Conclusion The transsphenoidal approach in a vidian neurectomy is a simple method that removes the need for sphenopalatine artery ligation and causes less surgical morbidity. However, the possibility of recurrence of this condition in the long term needs further investigation.


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