Spectrochim Acta A Mol Biomol Spectrosc. 2003 Jan 15;59(2):279-84.
Syntheses of steroid-based molecularly imprinted polymers and their molecular recognition study with spectrometric detection.
Dong H, Tong AJ, Li LD.
Department of Chemistry, Tsinghua University, Beijing 100084, People's Republic of China.
Recognition of five steroid compounds, beta-estradiol, ethynylestradiol, estradiolbenzoate, testosterone and methyltestosterone were studied using a synthesized molecularly imprinted polymer (MIP). When beta-estradiol was used as the template molecule, the polymer was synthesized with methacrylic acid (MAA) as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the cross linking agent through non-covalent interactions. It is found that the kind of porogen solvent and the polymerization conditions greatly affected the binding ability of a MIP to a certain molecule. Releasing of the template was performed by continuous extraction with methanol containing 10% acetic acid in a Soxhlet extractor. Our results indicated that such carefully synthesized MIP showed specific affinity toward beta-estradiol in the adsorption process.
J Steroid Biochem Mol Biol. 2002 Mar;80(3):291-7.
17beta-Estradiol inhibits cytokine induction of the human E-selectin promoter.
Tyree CM, Zou A, Allegretto EA.
Department of New Leads Discovery, Ligand Pharmaceuticals Inc., 10255 Science Center Road, San Diego, CA 92121, USA. ctyreeurogeneticsinc.com
Estradiol has been shown to decrease levels of the cell adhesion molecule E-selectin in cultured cells and in women on hormone replacement therapy. We set out to determine if the mechanism of estradiol action on E-selectin is at the level of its promoter. It was found that estradiol repressed the cytokine-stimulated induction of luciferase activity driven by the human E-selectin promoter in a reporter plasmid (hE-sel-LUC) in co-transfected human hepatoma cells (Hep G2) and human umbilical cord endothelial cells (ECV-304). Repression by estradiol was dependent on the presence of transfected estrogen receptor (ER) alpha or beta expression vectors. The ER antagonist ICI-182,780 blocked the repression by estradiol, confirming the receptor-dependence of the effect. The intact DNA-binding domain of ERalpha was required for estradiol repression of the cytokine-induced stimulation of the promoter in each cell line as demonstrated by the inability of an ER construct with two point mutations in the DNA-binding domain to inhibit reporter activity. Mutation of the NFK-B site at -94 to -85 within the E-selectin promoter led to less stimulation of hE-sel-LUC by interleukin one beta (IL-1beta). Estradiol did not inhibit this IL-1beta stimulated luciferase activity, indicating that the NFK-B site is necessary for ER-mediated inhibition of this promoter. Mutation of the AP-1 site at -500 to -494 within the E-selectin promoter had no effect on the ability of IL-1beta to stimulate its transcription, and estradiol repressed this activation in an ER-dependent manner with identical efficacy and potency in comparison with the wild-type promoter. Therefore, the E-selectin promoter is down-regulated by estradiol working thro
Food Chem Toxicol. 2002 May;40(5):643-51.
Comparison of the oestrogenic effects of infant milk formulae, oestradiol and the phytoestrogen coumestrol delivered continuously in the drinking water to ovariectomised mice.
Pocock VJ, Sales GD, Milligan SR.
Endocrinology and Reproduction Research Group, School of Biomedical Sciences, Guy's Campus, King's College, London SE1 1UL, UK.
The potential oestrogenic effects of infant milk formulae, coumestrol and oestradiol delivered in the drinking water were investigated in ovariectomised mice. None of the infant formulae tested (three soya, two cow's milk) produced any uterotrophic or mitotic responses in the reproductive tract, although the soya milks displayed weak oestrogenic activity in vitro. Studies of the interactions between coumestrol and oestradiol were undertaken to investigate claims that phytoestrogens may act as oestrogen antagonists. The responses to coumestrol (100 g/ml drinking water) and 17-oestradiol (100 ng/ml) given separately were similar. Combined administration begun simultaneously produced only additive effects on uterine weight and cell proliferation in the vagina and uterus. While pretreatment with coumestrol for 24 h reduced the mitotic response of the uterus 48 h after placement of an oestradiol implant, the uterine weight increase was unaffected and the apparent reduction in mitoses reflected the natural fluctuations in the underlying cycle of cell proliferation. These studies indicate that coumestrol acts as a typical oestrogen and shows only additive effects with oestradiol. The results also indicate that infant soya milk formulae do not constitute a large enough source of oestrogenic compounds to invoke oestrogenic effects in the reproductive tract of mature mice.
J Urol. 2003 May;169(5):1735-7.
Transdermal estradiol therapy for advanced prostate cancer--forward to the past?
Ockrim JL, Lalani EN, Laniado ME, Carter SS, Abel PD.
Department of Surgical Oncology, Faculty of Medicine, Imperial College, Hammersmith Hospitals NHS Trust, UK.
PURPOSE: Current hormonal therapies for prostate cancer are associated with significant morbidities, including symptoms of andropause and osteoporosis. Oral estrogens prevented many of these problems but were abandoned due to cardiovascular toxicity attributed to hepatic effect. In contrast, parenteral estrogens prevent first pass hepatic metabolism and substantially reduce cardiovascular risk, and long-term transdermal estradiol therapy is believed to be cardioprotective. We report preliminary results of a pilot study using transdermal estradiol therapy to treat men with advanced prostate cancer. MATERIALS AND METHODS: A total of 20 patients with advanced prostate cancer were enrolled in a before and after study that examined the impact of estradiol patches on hormones, disease, thrombophilia, vascular flow, osteoporosis and quality of life. RESULTS: Median followup is 15 months. Estradiol levels greater than 1,000 pmol./l. were achieved using 2 patches and higher levels were obtained by increasing the number of patches. All patients achieved castrate levels of testosterone within 3 weeks and had biochemical evidence of disease regression. One patient died of disease at 14 months and 1 cardiovascular complication occurred. Thrombophilic activation was avoided and vascular flow improved. Bone mineral density was significantly increased. Mild or moderate gynecomastia occurred in 80% of patients but no patient had hot flushes. All other functional and symptomatic quality of life domains improved. CONCLUSIONS: Transdermal estradiol therapy produced an effective tumor response. Cardiovascular toxicity was substantially reduced compared with that expected of oral estrogen, and other morbidity (gynecomastia) was negli
Eur Cytokine Netw. 2002 Jan-Mar;13(1):39-45.
Estradiol and raloxifene decrease the formation of multinucleate cells in human bone marrow cultures.
Ramalho AC, Couttet P, Baudoin C, Morieux C, Graulet AM, de Vernejoul MC, Cohen-Solal ME.
INSERM U. 349, Lariboisiere Hospital, 2, rue Ambroise-Pare, 75475 Paris Cedex 10 France.
Estrogen (E2) deficiency is responsible for increased bone turnover in the postmenopausal period, and it can be prevented by estrogen replacement therapy. The way estrogen acts on bone cells is not fully understood. Human bone marrow cell cultures may be a reliable model for studying the action of steroids on osteoclastogenesis in vitro. We examine the effects of estradiol and Raloxifene, a selective estrogen receptor modulator, on human primary bone marrow cells cultured for 15 days. 17beta-estradiol and Raloxifene significantly decreased the number of tartrate-resistant acid phosphatase multinucleate cells from osteoclast precursors on day 15. Estrogen receptor alpha (ER-alpha) mRNA was present in bone marrow mononuclear cells cultured for 5 days, but there was no estrogen receptor beta (ER-beta) mRNA, suggesting that this effect was mediated by ER-alpha. 15-day cultures no longer contained ER-alpha mRNA, suggesting that estrogen acts on early events of osteoclast differentiation. Finally, 10-8 M 17beta-estradiol has no effect on the release of IL-6 and IL-6-sr into the medium of marrow mononuclear cells cultured for 5 or 15 days. Osteoclast apoptosis was not affected by estradiol or Raloxifene after 15 days of culture under our conditions. In conclusion, we have shown that both estradiol and Raloxifene inhibit osteoclast differentiation in human bone marrow mononuclear cultures. The biological effect that can mimic in vivo differentiation could be mediated through ER-alpha.
Steroids. 2002 Apr;67(5):339-46.
Acute relaxant effects of 17-beta-estradiol through non-genomic mechanisms in rabbit carotid artery.
Salom JB, Burguete MC, Perez-Asensio FJ, Centeno JM, Torregrosa G, Alborch E.
Centro de Investigacion, Hospital Universitario La Fe, Valencia, Spain. salom_jbva.es
Estrogens could play a cardiovascular protective role not only by means of systemic effects but also by means of direct effects on vascular structure and function. We have studied the acute effects and mechanisms of action of 17-beta-estradiol on vascular tone of rabbit isolated carotid artery. 17-Beta-estradiol (10, 30, and 100 microM) elicited concentration-dependent relaxation of 50 mM KCl-induced active tone in male and female rabbit carotid artery. The stereoisomer 17-alpha-estradiol showed lesser relaxant effects in male rabbits. Endothelium removal did not modify relaxation induced by 17-beta-estradiol. The NO synthase inhibitor L-NAME (100 microM) only reduced significantly relaxation produced by 30 microM 17-beta-estradiol. Relaxation was not modified by the estrogen receptor antagonist ICI 182,780 (1 microM), the protein synthesis inhibitor cycloheximide (1 microM), and the selective K(+) channel blockers charybdotoxin (0.1 microM) and glibenclamide (1 microM). CaCl(2) (30 microM -10 mM) induced concentration-dependent contraction in rabbit carotid artery depolarized by 50 mM KCl in Ca(2+) free medium. Preincubation with 17-beta-estradiol (3, 10, 30, or 100 microM) or the L-type Ca(2+) channel blocker nicardipine (0.01, 0.1, 1, or 10 nM) produced concentration-dependent inhibition of CaCl(2)-induced contraction. In conclusion, 17-beta-estradiol induces endothelium-independent relaxation of rabbit carotid artery, which is not mediated by classic estrogen receptor and protein synthesis activation. The relaxant effect is due to inhibition of extracellular Ca(2+) influx to vascular smooth muscle, but activation of K(+) efflux is not involved. Relatively high pharmacological concentr
J Appl Physiol. 2002 May;92(5):2035-44.
Estrogen has opposing effects on vascular reactivity in obese, insulin-resistant male Zucker rats.
Brooks-Asplund EM, Shoukas AA, Kim SY, Burke SA, Berkowitz DE.
Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
We hypothesized that estradiol treatment would improve vascular dysfunction commonly associated with obesity, hyperlipidemia, and insulin resistance. A sham operation or 17beta-estradiol pellet implantation was performed in male lean and obese Zucker rats. Maximal vasoconstriction (VC) to phenylephrine (PE) and potassium chloride was exaggerated in control obese rats compared with lean rats, but estradiol significantly attenuated VC in the obese rats. Estradiol reduced the PE EC50 in all groups. This effect was cyclooxygenase independent, because preincubation with indomethacin reduced VC response to PE similarly in a subset of control and estrogen-treated lean rats. Endothelium-independent vasodilation (VD) to sodium nitroprusside was similar among groups, but endothelium-dependent VD to ACh was significantly impaired in obese compared with lean rats. Estradiol improved VD in lean and obese rats by decreasing EC50 but impaired function by decreasing maximal VD. The shift in EC50 corresponded to an upregulation in nitric oxide synthase III protein expression in the aorta of the estrogen-treated obese rats. In summary, estrogen treatment improves vascular function in male insulin-resistant, obese rats, partially via an upregulation of nitric oxide synthase III protein expression. These effects are counteracted by adverse factors, such as hyperlipidemia and, potentially, a release of an endothelium-derived contractile agent.
J Pharmacol Exp Ther. 2002 May;301(2):631-7.
Nongenomic regulation of the kinetics of exocytosis by estrogens.
Machado JD, Alonso C, Morales A, Gomez JF, Borges R.
Unidad de Farmacologia, Facultad de Medicina, Universidad de La Laguna, Tenerife, Spain.
The role of nongenomic action of estrogens on elicited catecholamine secretion and exocytosis kinetics was studied in perfused rat adrenals and in cultured bovine chromaffin cells. 17beta-Estradiol as well as the estrogen receptor modulators raloxifene and LY117018, but not 17alpha-estradiol, inhibited at the micromolar range the catecholamine output elicited by acetylcholine or high potassium. However, these agents failed to modify the secretion elicited by high Ca(2+) in glands treated with the ionophore A-23187 (calcimycin), suggesting that estrogens did not directly act on the secretory machinery. At the single cell level, estrogens modified the kinetics of exocytosis at nanomolar range. All of the drugs tested except 17alpha-estradiol produced a profound slowing down of the exocytosis as measured by amperometry. LY117018 also reduced the granule content of catecholamines. 17beta-Estradiol reduced the intracellular free Ca(2+) but only at micromolar concentrations, whereas nanomolar concentrations increased the cAMP levels. These effects were reproduced with the nonpermeable drug 17beta-estradiol-horseradish peroxidase and antagonized with nanomolar concentrations of the antiestrogen ICI 182,780 (fulvestrant). Our data suggest the presence of membrane sites that regulate both the exocytotic phenomenon and the total catecholamine release with high and low affinity, respectively.
Arch Androl. 2002 May-Jun;48(3):225-32.
Seminal plasma melatonin and gonadal steroids concentrations in normal men.
Luboshitzky R, Shen-Orr Z, Herer P.
Endocrine Institute, Haemek Medical Center, Afula, Israel. luboshitzky_rclalit.org.il
The authors determined semen quality and the concentrations of estradiol, testosterone, and melatonin in blood and seminal plasma of 8 normal men. To investigate the reproducibility of these parameters, semen analysis and hormone concentrations were determined on 3 occasions, 6 weeks apart. All 8 men had normal semen analysis. Blood melatonin (9.7-45.4 pg/mL) and testosterone (3.5-12.3 ng/mL) levels were significantly higher than the comparable seminal plasma levels (0.6-5.0 pg/mL, p <.02; 0.1-0.9 ng/mL, p <.0001, respectively). Seminal plasma estradiol levels (46.9-91.3 pg/mL) were significantly higher than the blood levels (13.3-44.7 pg/mL) (p <.0001). The intraindividual variations in seminal plasma estradiol levels ranged between 8.7 and 13.8%. There was no correlation between sperm concentration, motility or morphology and blood or seminal plasma hormone levels. Also, blood and seminal plasma hormone levels were not correlated. These results indicate that in normospermic men seminal plasma estradiol levels are higher than blood hormone levels, suggesting local production of estradiol. This may imply that estrogen and/or the balance andorgen/estrogen is important in normal human spermatogenesis.
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