Mol Cell Endocrinol. 2002 Jun 28;192(1-2):1-6.
17beta-Estradiol upregulates distinct maxi-K channel transcripts in mouse uterus.
Holdiman AJ, Fergus DJ, England SK.
Department of Physiology and Biophysics, 5-660 Bowen Science Building, University of Iowa, Iowa City, IA 52242, USA.
The mouse maxi-K channel transcript undergoes alternative splicing to produce isoforms differing in sensitivity to intracellular regulators. We hypothesized that 17beta-estradiol could induce myometrial maxi-K channel transcripts to differentially splice. Polymerase chain reaction demonstrated two products at site D in mice injected with either 8.5 microg of 17beta-estradiol for 4 days or a vehicle control. Splicing of site D is known to modulate the sensitivity of the maxi-K channel to calcium and voltage. RNase protection analyses revealed that the alpha subunit transcript, and an exon encoding 59 amino acids at site D that enhances Ca(2+)- and voltage-sensitivity, are upregulated approximately 1.4-fold after 17beta-estradiol stimulation however, the insertless isoform of this transcript is enhanced approximately 5-fold. Immunoblotting demonstrates that the total maxi-K channel alpha subunit expression mimics transcript regulation. These findings verify that maxi-K channel transcripts are differentially spliced by 17beta-estradiol, which may contribute to stoichiometric changes in isoform expression during pregnancy.
Neuroendocrinology. 2002 Jul;76(1):8-17.
Regulation of expression of somatostatin genes by sex steroid hormones in goldfish forebrain.
Canosa LF, Lin X, Peter RE.
Biological Sciences Department, University of Alberta, Edmonton, Alta., Canada.
Recently, our laboratory has identified three distinct pre-pro-somatostatin (PSS) genes in goldfish brain: PSS-I encodes for somatostatin (SRIH)-14, PSS-II encodes SRIH-28, which contains [Glu(1), Tyr(7), Gly(10)] SRIH-14 at its C-terminus, and PSS-III encodes [Pro(2)] SRIH-14. In goldfish, increasing levels of the sex steroid estradiol increase the plasma levels of growth hormone (GH). However, whether sex steroids act at the level of the brain to regulate GH release is unclear. In the present study, the effects of sex steroids on the expression of the three PSS genes in goldfish forebrain were examined. The results demonstrate that treatment with estradiol significantly increases the expression of PSS-I and PSS-III genes in both male and female fish. The effects of estradiol were evident after only 2.5 days of treatment. Testosterone treatment increased the expression of PSS-I and PSS-III genes in female but not male fish, and only at the highest dose used. In addition, the effects of testosterone were evident only after treatment for 5 or 10 days and were blocked by an aromatase inhibitor, suggesting that testosterone must be converted to estradiol to exhibit the effect. Neither estradiol nor testosterone treatment had effects on the expression of the PSS-II gene. These results suggest that sex steroids can act either directly or indirectly on the brain to regulate PSS-I and PSS-III gene expression, influencing in turn the regulation of GH secretion. Copyright 2002 S. Karger AG, Basel
Am J Cardiol. 2002 Jul 3;90(1A):11F-16F.
Arch Surg. 2002 Jan;137(1):74-9.
Estradiol administration improves splanchnic perfusion following trauma-hemorrhage and sepsis.
Kuebler JF, Jarrar D, Toth B, Bland KI, Rue L 3rd, Wang P, Chaudry IH.
Center for Surgical Research, University of Alabama at Birmingham, Volker Hall G094, 1670 University Blvd, Birmingham, AL 35294-0019, USA.
HYPOTHESIS: The female sex steroid 17beta-estradiol improves immune functions following trauma-hemorrhage in rodent models. Therefore, we hypothesized that 17beta-estradiol administration following trauma-hemorrhage would also improve cardiac output, splanchnic perfusion, and oxygen utilization, even after the induction of subsequent sepsis. SETTING: A university laboratory. INTERVENTION: Male rats underwent midline laparotomy (ie, soft tissue injury). They were bled to a mean arterial pressure of 35 to 40 mm Hg for 90 minutes and resuscitated over 60 minutes with lactated Ringer solution. At the beginning of resuscitation, 17beta-estradiol (l mg/kg) or a vehicle was administered. At 20 hours after resuscitation, polymicrobial sepsis was induced by cecal ligation and puncture (CLP). MAIN OUTCOME MEASURES: At 5 hours after CLP, cardiac performance (via a left ventricular catheter), cardiac output, and organ blood flow were determined using strontium 85 microspheres. Blood samples were collected from the femoral artery and jugular, portal, and renal veins to determine systemic and regional oxygen delivery and consumption. Moreover, circulating levels of 17beta-estradiol, its adrenal precursor dehydroepiandrosterone (DHEA), and corticosterone were assessed by enzyme-linked immunosorbent assay. RESULTS: Hemorrhage and subsequent sepsis significantly depressed cardiac performance, cardiac output, organ perfusion, and oxygen consumption. Estrogen did not restore cardiac output or systemic oxygen consumption; nonetheless, it restored the depressed intestinal perfusion. Rats treated with estrogen had significantly elevated levels of plasma 17beta-estradiol, bu
Reprod Fertil Dev. 2001;13(4):297-305.
Estrogen sulfamates: a new approach to oral estrogen therapy.
Elger W, Barth A, Hedden A, Reddersen G, Ritter P, Schneider B, Zuchner J, Krahl E, Muller K, Oettel M, Schwarz S.
EnTec GmbH Jena, Germany. entec-online.de
Sulfamate substitution (-O-SO2-NH2) at carbon atom 3 of the steroid skeleton leads to orally active prodrugs of estrogens with much higher systemic, but lower hepatic, estrogenic activity than their parent steroids. This dissociation is achieved by first passage through the liver in erythrocytes, followed by systemic hydrolysis which releases the 'parent' estrogen. In the rat, orally administered tritiated estradiol sulfamate, unlike estradiol, appears in the circulation at high concentrations. At Cmax, approximately one third of the administered dose forms a depot in the circulation (98% in erythrocytes, 2% in plasma). Significant estradiol, estrone and estrone sulfate concentrations were recorded in plasma during depletion of the red blood cell pool. Estradiol sulfamate (J995) has no estrogen receptor affinity per se or estrogenic activity in vitro ( i.e. without hydrolysis). Its oral uterotropic activity in rats is approximately 100 times greater than that of estradiol, however, its hepatotropic activity is only marginally elevated. These functions include bile secretion, the secretion of angiotensinogen, lipoproteins (total and high-density lipoprotein cholesterol) and insulin-like growth factor I (IGF-I). Orally administred estradiol sulfamate led to systemic estrogenic effects without significant hepatic responses, whereas estradiol and other 'conventional' estrogens exerted parallel systemic and hepatic estrogenic effects. Sulfamate technology represents an approach to the use of natural estrogens for fertility control and hormone replacement therapy in both genders. In this context, reduced effects on hemostatic factors, angiotensinogen, bile and IGF-I secretion seem the most important aspects. In addition, blood concentratio
Pharmacology. 2002 Feb;64(2):84-90.
Effect of 17beta-estradiol on intracellular Ca(2+) levels in renal tubular cells.
Chen WC, Cheng JS, Chou KJ, Tang KY, Huang JK, Tseng LL, Wang JL, Lee KC, Jan CR.
Division of Urology, Ping Tung Christian Hospital, Ping Tung, Taiwan.
The effect of 17beta-estradiol on intracellular Ca(2+) concentrations ([Ca(2+)](i)) in Madin Darby canine kidney cells was investigated by using the fluorescent dye fura-2. 17Beta-estradiol (5-100 micromol/l) induced instantaneous increases in [Ca(2+)](i) in a concentration-dependent manner. Ca(2+) removal inhibited 45 +/- 15% of the Ca(2+) signal. In Ca(2+)-free medium, pretreatment with 50 micromol/l 17beta-estradiol abolished the [Ca(2+)](i) increases induced by 2 micromol/l carbonylcyanide m-chlorophenylhydrazone (CCCP; a mitochondrial uncoupler), 1 micromol/l thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor) and 50 micromol/l brefeldin A (an antibiotic which disperses the Golgi complex), but pretreatment with brefeldin A, CCCP and thapsigargin only partly inhibited the 17beta-estradiol-induced [Ca(2+)](i) signal. Adding 3 mmol/l Ca(2+) increased [Ca(2+)](i) in cells pretreated with 5-100 micromol/l 17beta-estradiol in Ca(2+)-free medium. Pretreatment with 1 micromol/l U73122 to abolish the formation of inositol-1,4,5-trisphosphate inhibited 50% of the Ca(2+) release induced by 50 micromol/l 17beta-estradiol. 17Beta-estradiol (20 micromol/l) also increased [Ca(2+)](i) in human bladder cancer cells and prostate cancer cells. Collectively, this study shows that 17beta-estradiol evoked a significant internal Ca(2+) release and external Ca(2+) entry possibly in a nongenomic manner. Copyright 2002 S. Karger AG, Basel
J Mol Biol. 2002 Jan 25;315(4):699-712.
Highly specific anti-estradiol antibodies: structural characterisation and binding diversity.
Monnet C, Bettsworth F, Stura EA, Le Du MH, Menez R, Derrien L, Zinn-Justin S, Gilquin B, Sibai G, Battail-Poirot N, Jolivet M, Menez A, Arnaud M, Ducancel F, Charbonnier JB.
Departement d'Ingenierie et d'Etude des Proteines, CEA, CE Saclay, Gif-sur-Yvette Cedex, 91191, France.
Subtle modulation of antibody-binding properties by protein engineering often lies with an accurate structural and energetic description of how an antigen is recognised. Thus, with the intent to increase the affinity and add a bias in favour of natural estradiol compared with its chemically modified immunogen, we have determined the crystal structure of two anti-estradiol monoclonal antibodies, 10G6D6 and 17E12E5. Although generated against the same estradiol derivative, these antibodies share little sequence identity, which is reflected in dissimilar binding pockets and in different positioning of the steroid. In both antibodies the characteristic 17-hydroxyl group is buried deeply at the bottom of hydrophobic pockets and stabilised by hydrogen bonds. Apart from this similarity, the steroid is oriented differently in the respective binding pockets. The high specificity of both antibodies has been mapped out, and even closely related steroids show low cross-reactivity. The structural studies of the complex formed between 10G6D6 and 6-CMO-estradiol have identified contacts between the 6-CMO coupling linker and an arginine residue from the heavy chain CDR2 segment. This segment is now being targeted by random mutagenesis to select mutants with a preference for natural estradiol compared to the branched hapten. Copyright 2002 Academic Press.
Anim Reprod Sci. 2002 Feb 15;69(3-4):175-86.
Steroidogenesis in cumulus cells of bovine cumulus-oocyte-complexes matured in vitro with BSA and different concentrations of steroids.
Mingoti GZ, Garcia JM, Rosa-e-Silva AA.
Department of Animal Health, UNESP, P.O. Box 341, CEP 16050-680, Aracatuba, SP, Brazil. gmingotmva.uesp.br
The present in vitro experiments were designed to evaluate the ability of bovine cumulus-oocyte-complexes (COCs) to produce steroids and also to evaluate the modulatory effects of added estradiol, progesterone and testosterone on the steroidogenic activity of COCs. Considerable estradiol accumulation was observed in the control maturation medium for in vitro maturation of bovine COCs during the 24h of maturation (P<0.05). When testosterone was added to the medium at various concentrations, a slight estradiol accumulation occurred, which, however, was lower (P<0.05) than that observed in the control medium. Slight estradiol accumulation was observed in maturation medium containing progesterone at concentrations of 2.5, 5.0 and 10.0 microg/ml, but these increases were less (P<0.05) than those observed in the control medium. However, in the presence of 1.0 microg/ml progesterone, estradiol accumulation was equal to that of the control medium (P>0.05). Progesterone accumulation (P<0.05) was observed in the control medium for in vitro maturation of bovine COCs. When estradiol was added to the maturation medium, progesterone accumulation was observed, but was significant (P<0.05) only when the medium was supplemented with the lesser concentrations of estradiol utilized in the experiment (1.0 microg/ml). The results demonstrated that (1) cumulus cells of bovine COCs are able to secrete estradiol and progesterone in culture systems for in vitro maturation, and this steroidogenesis is modulated by the steroids progesterone, testosterone and estradiol, and (2) the addition of estradiol to the in vitro maturation medium of bovine oocytes should be reviewed, since
Int J Clin Pharmacol Ther. 2003 Apr;41(4):148-52.
Endogenous estradiol metabolites stimulate the in vitro proliferation of human osteoblastic cells.
Seeger H, Hadji P, Mueck AO.
Section of Endocrinology and Menopause, Women's University Hospital, Tubingen, Germany.
OBJECTIVES: Evidence is accumulating that estradiol metabolites are not merely waste products but may play physiologic and pathophysiologic roles. In the present study, effect of estradiol metabolites on the proliferation of human female osteoblasts was investigated for the first time and compared to effect of their parent substance 17beta-estradiol. MATERIALS AND METHODS: Osteoblasts from female hipbone were incubated with estradiol and estradiol metabolites at dosages of 10(-9), 10(-7) and 10(-5) M for 7 days. Cell proliferation was measured using a cell counter. RESULTS: Estradiol had no effect on cell proliferation at the tested concentrations. In contrast, the A-ring metabolites 2-hydroxyestrone, 2-hydroxyestradiol, 2-hydroxyestriol, 4-hydroxyestrone and 4-hydroxyestradiol displayed significant increases in cell proliferation, although only at high physiologic or pharmacologic dosages. Methylation ofthese metabolites completely abolished their proliferating property. For the D-ring metabolites estrone, estriol, estetrol and 16alpha-hydroxyestrone, no significant changes in cell proliferation were observed. CONCLUSION: The present results suggest that endogenous estradiol metabolites are capable of stimulating the proliferation of human female osteoblastic cells. None of the estradiol metabolites examined inhibited cell proliferation. Thus, estradiol metabolism may play a decisive role in development and maintenance of bone mass.
Appl Environ Microbiol. 2002 Feb;68(2):859-64.
Biotransformation and bioconcentration of steroid estrogens by Chlorella vulgaris.
Lai KM, Scrimshaw MD, Lester JN.
Environmental Processes and Water Technology Group, Department of Environmental Science and Technology, Imperial College of Science, Technology and Medicine, London SW7 2BP, United Kingdom.
The biotransformation and bioconcentration of natural and synthetic steroid estrogens by Chlorella vulgaris were investigated by using batch-shaking experiments with incubation for 48 h in the light or dark. Estradiol and estrone were interconvertible in both light and dark conditions; however, this biotransformation showed a preference for estrone. In the light, 50% estradiol was further metabolized to an unknown product. Apart from biotransformation, estrone, as well as hydroxyestrone, estriol, and ethinylestradiol, was relatively stable in the algal culture, whereas estradiol valerate was hydrolyzed to estradiol and then to estrone within 3 h of incubation. All of the tested estrogens exhibited a degree of partitioning to C. vulgaris; however, the concentrations of estriol, hydroxyestrone, ethinylestradiol, and estradiol valerate were always below the quantification limits. For estradiol and estrone, the partitioning of these estrogens in the algal extracts to the filtrates was <6% of the total amount present. The average concentration factor for estrone was ca. 27; however, the concentration factor for estradiol was not reported since no equilibrium was reached between the aqueous solution and that within the cells due to continuing biotransformation.
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