J Clin Endocrinol. 1972 January;34:243-6.
Preliminary isolation of an estrogen specific binding macromolecule from the human uterus.

Mcguire JL, Bariso CD, Fuller BS, Mcelrath TG, Delahunte JM.

PIP: A preliminary isolation of an estrogen specific binding macromolecule from the human uterus is described. Tritiated-estradiol-17beta was incubated with uterine cytosol fractions (273,000 g supernatant) and various nonradioactive steroids. Sucrose gradient centrifugation was employed in isolating the human estrogen, and bound steroids were separated from the unbound by dextran-coated charcoal. Only nonlabeled estrogens depressed the quantity of bound estradiol. Ethynyl estradiol, estriol, and estradiol-17beta competitively inhibited tritiated-estradiol binding, whereas, cholesterol, cortisol, testosterone, progesterone, and norethindrone did not. Sucrose density gradient ultracentrifugation also revealed binding of estradiol to uterine cytosol. It is concluded that these data sugges t the presence of an estrogen-binding macromolecule in the human uterus similar to that in lower mammals making various hormone receptor studies applicable to both man and mammals.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12332921&dopt=Abstract estradiol




Eur J Obstet Gynecol Reprod Biol. 2003 Apr 25;107(2):163-7.
Tocolytic effects of formoterol are associated with local change in the progesterone/estradiol ratio.

Shinkai N, Sasaki H, Okumura Y, Saito H, Takasuna K, Takayama S.

Daiichi Pharmaceutical Co Ltd, 8-1 Minamisakae-cho, Kasukabe, Saitama 344-0067, Japan. shinkadsk.co.jp

OBJECTIVE: The aim of the study was to determine whether a beta(2)-adrenoceptor agonist, formoterol, inhibits premature delivery in connection with change in estradiol and progesterone concentrations in the amniotic fluid in ovariectomized rats. STUDY DESIGN: Pregnant rats at the 15th day of gestation were bilaterally ovariectomized and given injection of 17beta-estradiol immediately after the operation and every 24 h. An osmotic pump filled with a solution of formoterol or saline was also implanted subcutaneously into the back of each. The animals were killed by decapitation under light ether anesthesia 18, 36, 54 or 72 h after ovariectomy, and the numbers of undelivered fetuses and newborn were counted. Amniotic fluid was collected 16, 36, and 54 h after ovariectomy. RESULTS: Formoterol (0.15 mg/(kg h)) reversed the decline in premature delivered fetuses due to 17beta-estradiol 54 and 72 h after ovariectomy. Although no influence was evident regarding the progesterone and estradiol concentrations in amniotic fluid in ovariectomized rats supplemented with 17beta-estradiol, formoterol significantly inhibited the increment in the estradiol/progesterone ratio as well as the elevation in prostaglandin F2alpha concentration. CONCLUSION: These findings indicate that tocolytic effects of formoterol may be associated with suppression of uterine activity due to modulation of hormone secretion. Copyright 2002 Elsevier Science Ireland Ltd.

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Mol Endocrinol. 2002 Oct;16(10):2255-65.
Estradiol feedback alters potassium currents and firing properties of gonadotropin-releasing hormone neurons.

DeFazio RA, Moenter SM.

Department of Internal Medicine, University of Virginia, Charlottesville, Virginia 22908-0578, USA.

GnRH neurons are regulated by estradiol feedback through unknown mechanisms. Voltage-gated potassium channels determine the pattern of activity and response to synaptic inputs in many neurons. We used whole-cell patch-clamp to test whether estradiol feedback altered potassium currents in GnRH neurons. Adult mice were ovariectomized and some treated with estradiol implants to suppress reproductive neuroendocrine function; 1 wk later, brain slices were prepared for recording. Estradiol affected the amplitude, decay time, and the voltage dependence of both inactivation and activation of A-type potassium currents in these cells. Estradiol also altered a slowly inactivating current, I(K.) The estradiol-induced changes in I(A) contributed to marked changes in action potential properties. Estradiol increased excitability in GnRH neurons, decreasing both threshold and latency for action potential generation. To test whether estradiol altered phosphorylation of the channels or associated proteins, the broad-spectrum kinase inhibitor H7 was included in the recording pipette. H7 acutely reversed some but not all effects of estradiol on potassium currents. Estradiol did not affect I(A) or I(K) in paraventricular neurosecretory neurons, demonstrating a degree of specificity in these effects. Potassium channels are thus one target for estradiol regulation of GnRH neurons; this regulation involves changes in phosphorylation of potassium channel components.

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Am J Physiol Cell Physiol. 2002 Nov;283(5):C1461-8.
Essential role of Ca2+ -dependent phospholipase A2 in estradiol-induced lysosome activation.

Burlando B, Marchi B, Panfoli I, Viarengo A.

Dipartimento di Scienze e Tecnologie Avanzate, Universita del Piemonte Orientale Amedeo Avogadro, 15100 Alessandria, Biologia e Genetica, Universita di Genova, 16132 Genoa, Italy. burlandnipmn.it

The mechanism of lysosome activation by 17beta-estradiol has been studied in mussel blood cells. Cell treatment with estradiol induced a sustained increase of cytosolic free Ca2+ that was completely prevented by preincubating the cells with the Ca2+ chelator BAPTA-AM. Estradiol treatment was also followed by destabilization of the lysosomal membranes, as detected in terms of the lysosomes' increased permeability to neutral red. The effect of estradiol on lysosomes was almost completely prevented by preincubation with the inhibitor of cytosolic Ca2+ -dependent PLA2 (cPLA2), arachidonyl trifluoromethyl ketone (AACOCF3), and was significantly reduced by preincubation with BAPTA-AM. In contrast, it was virtually unaffected by preincubation with the inhibitor of Ca2+ -independent PLA2, (E)-6-(bromomethylene)tetrahydro-3-(1-naphtalenyl)-2H-pyran-2-one (BEL). The Ca2+ ionophore A-23187 yielded similar effects on [Ca2+](i) and lysosomes. Exposure to estradiol also resulted in cPLA2 translocation from cytosol to membranes, lysosome enlargement, and increased protein degradation. These results suggest that the destabilization of lysosomal membranes following cell exposure to estradiol occurs mainly through a Ca2+ -dependent mechanism involving activation of Ca2+ -dependent PLA2. This mechanism promotes lysosome fusion and catabolic activities and may mediate short-term estradiol effects.

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Neurosci Lett. 2002 Oct 25;332(1):65-9.
Enhancement of rat hippocampal long-term potentiation by 17 beta-estradiol involves mitogen-activated protein kinase-dependent and -independent components.

Kim JS, Kim HY, Kim JH, Shin HK, Lee SH, Lee YS, Son H.

Department of Biochemistry, Hanyang University College of Medicine, 17 Haengdang-dong, Sungdong-gu, Seoul 133-791, South Korea.

To investigate if estrogen modulates long-term potentiation (LTP) via mitogen-activated protein kinase (MAPK) activation, in vitro hippocampal slices were used to induce LTP through extracellular field recordings. Slices perfused with 17beta-estradiol exhibited a significant enhancement of LTP (224+/-19%) compared with LTP in control slices (157+/-9%). In the presence of PD098059, 17beta-estradiol still produced a significant magnitude of LTP (131+/-7%), revealing the existence of p-MAPK-independent LTP mediated by 17beta-estradiol. Immunocytochemistry showed that 17beta-estradiol promoted a transient increase in nuclear translocation of p-MAPK. 17beta-estradiol induced the extracellular proteolysis of neural cell adhesion molecule in a p-MAPK-independent manner, indicating that 17beta-estradiol may act on synaptic remodeling. These results indicate that 17beta-estradiol might affect hippocampal synaptic plasticity in a way involving two separate pathways, which are MAPK-dependent and MAPK-independent.

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Horm Metab Res. 2002 Sep;34(9):530-4.
Effects of 17beta-estradiol on blood-brain barrier disruption during focal ischemia in rats.

Chi OZ, Liu X, Weiss HR.

Department of Anesthesia, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901-1977, USA. chmdnj.edu

This study was performed to test whether 17beta-estradiol could attenuate the blood-brain barrier disruption caused by middle cerebral artery occlusion in the ovariectomized rats. Rats aged twelve to fourteen weeks were used in this study. Their ovaries were removed one week prior to the implantation of the pellets. For the 17beta-estradiol group, a 500 microg 17beta-estradiol 21 day-release pellet was implanted and for the control group, a vehicle pellet was implanted 21 days before the experiments. One hour after middle cerebral artery occlusion under isoflurane anesthesia, the transfer coefficient of 14C-alpha-aminoisobutyric acid (104 Daltons) and the volume of 3H-dextran (70,000 Daltons) distribution were determined to represent the degree of blood-brain barrier disruption. Blood pressures and blood gases were similar between controls and 17beta-estradiol-treated rats. In both groups, the transfer coefficient of the ischemic cortex was higher than that of the corresponding contralateral cortex (control: Ischemic Cortex 12.5 +/- 5.9 microl/g/min, Contralateral Cortex 3.0 +/- 1.6, p < 0.001; 17beta-estradiol: Ischemic Cortex 6.7 +/- 3.3 micro l/g/min, Contralateral Cortex 2.2 +/- 0.9, p < 0.01). There was no significant difference in the transfer coefficient of the contralateral cortex between these two groups. However, the transfer coefficient of the Ischemic Cortex of the 17beta-estradiol-treated animals was 46 % lower than that of the control, vehicle-treated rats (p < 0.05). The increase of the volume of 3H-dextran distribution with middle cerebral artery occlusion was significant in the vehicle-treated rats (Ischemic Cortex: 6.4 +/- 2.7 ml/100 g, Cont




Maturitas. 2002 Oct 25;43(2):87-93.
Impact of hormone replacement therapy on endogenous estradiol metabolism in postmenopausal women.

Mueck AO, Seeger H, Wallwiener D.

Department of Obstetrics and Gynecology, Section of Endocrinology and Menopause, University of Tuebingen, Calwerstrasse 7, 72 076, Tuebingen, Germany. endo.mened.uni-tuebingen.de

OBJECTIVES: Changes in estradiol metabolism may play a role in the pathophysiology of different diseases, of special interest being an increase in D-ring over A-ring metabolites for the risk of breast cancer. In the present work we investigated the effect of exogenous estradiol therapy on endogenous estradiol metabolism in postmenopausal women. METHODS: Three different studies were carried out in 126 women: in study A the women were treated for 4 weeks either with oral or with transdermal 17beta-estradiol, in study B for 4 weeks with oral or transdermal 17beta-estradiol sequentially combined with oral or transdermal norethisterone acetate, and in study C for 12 weeks either with oral 17beta-estradiol or with an oral continuous combination of 17beta-estradiol with the new progestin dienogest. As main representatives of the A- and D-ring metabolism, 2-hydroxyestrone (2-OHE1) and 16 alpha-hydroxyestrone (16-OHE1), respectively, were measured in 8 h night urine using enzyme immunoassay technique. RESULTS: Oral estradiol treatment resulted in a significant higher excretion of estradiol metabolites compared to transdermal treatment. Neither oral nor transdermal estradiol induced a significant change in the ratio of 16-OHE1 to 2-OHE1. The addition of oral or transdermal norethisterone acetate to estradiol did not alter on average the endogenous estradiol metabolism, although in individual patients a significant increase in 16-OHE1 metabolism was observed only with oral norethisterone. The continuous oral addition of dienogest did not lead to any significant change in estradiol metabolism. CONCLUSIONS: These results indicate that oral estradiol replac




Drug Metab Dispos. 2002 Nov;30(11):1266-73.
Differential modulation of UDP-glucuronosyltransferase 1A1 (UGT1A1)-catalyzed estradiol-3-glucuronidation by the addition of UGT1A1 substrates and other compounds to human liver microsomes.

Williams JA, Ring BJ, Cantrell VE, Campanale K, Jones DR, Hall SD, Wrighton SA.

Department of Drug Disposition, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285, USA.

Previous results demonstrating homotropic activation of human UDP-glucuronosyltransferase (UGT) 1A1-catalyzed estradiol-3-glucuronidation led us to investigate the effects of 16 compounds on estradiol glucuronidation by human liver microsomes (HLM). In confirmation of previous work using alamethicin-treated HLM pooled from four livers, UGT1A1-catalyzed estradiol-3-glucuronidation demonstrated homotropic activation kinetics (S(50) = 22 microM, Hill coefficient, n = 1.9) whereas estradiol-17-glucuronidation (catalyzed by other UGT enzymes) followed Michaelis-Menten kinetics (K(m) = 7 microM). Modulatory effects of the following compounds were investigated: bilirubin, eight flavonoids, 17alpha-ethynylestradiol (17alpha-EE), estriol, 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine (PhIP), anthraflavic acid, retinoic acid, morphine, and ibuprofen. Although the classic UGT1A1 substrate bilirubin was a weak competitive inhibitor of estradiol-3-glucuronidation, the estrogens and anthraflavic acid activated or inhibited estradiol-3-glucuronidation dependent on substrate and effector concentrations. For example, at substrate concentrations of 5 and 10 microM, estradiol-3-glucuronidation activity was stimulated by as much as 80% by low concentrations of 17alpha-EE but was unaltered by flavanone. However, at higher substrate concentrations (25-100 microM) estradiol-3-glucuronidation was inhibited by about 55% by both compounds. Anthraflavic acid and PhIP were also stimulators of estradiol 3-glucuronidation at low substrate concentrations. The most potent inhibitor of estradiol 3-gl




Am J Physiol Heart Circ Physiol. 2002 Dec;283(6):H2389-96. Epub 2002 Sep 12.
Acute effects of 17beta -estradiol on femoral veins from adult gonadally intact and ovariectomized female pigs.

Bracamonte MP, Jayachandran M, Rud KS, Miller VM.

Department of Physiology and Biophysics, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.

Our experiments were designed to determine the acute effects of 17beta-estradiol on femoral veins from intact and ovariectomized female pigs. Rings of femoral veins with or without endothelium were suspended in organ chambers for measurement of isometric force. Concentration-response curves to 17beta-estradiol (10(-9) to 10(-5) M) were obtained in veins contracted with prostaglandin F(2alpha) in the absence and presence of inhibitors of either estrogen receptors (ICI-182780; 10(-5) M), nitric oxide synthase [N(G)-monomethyl-l-arginine (l-NMMA); 10(-4) M], soluble guanylate cyclase (1-H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one; 10(-5) M), or potassium channels (tetraethylammonium; 10(-2) M). Estrogen receptors were identified with the use of Western blotting and immunostaining in veins of both groups. 17beta-Estradiol caused acute endothelium-dependent relaxations in both groups. Relaxations to 17beta-estradiol were inhibited by l-NMMA and 1-H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one but not ICI-182780. Tetraethylammonium inhibited relaxations only in veins with endothelium from intact females. Results indicate that 17beta-estradiol causes acute endothelium-dependent relaxations in femoral veins. The relative contribution of nitric oxide and K(+) channels as mechanisms involved in relaxations to 17beta-estradiol in femoral veins is modulated by ovarian status.

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