Search results for "Estradiol"
showing 10 items of 203 documents
Diacylglycerol kinase α mediatses 17-β-estradiol-induced proliferation, motility, and anchorage-independent growth of Hec-1A endometrial cancer cell …
2011
Increased levels of endogenous and/or exogenous estrogens are one of the well known risk factors of endometrial cancer. Diacylglycerol kinases (DGKs) are a family of enzymes which phosphorylate diacylglycerol (DAG) to produce phosphatidic acid (PA), thus turning off and on DAG-mediated and PA-mediated signaling pathways, respectively. DGK α activity is stimulated by growth factors and oncogenes and is required for chemotactic, proliferative, and angiogenic signaling in vitro. Herein, using either specific siRNAs or the pharmacological inhibitor R59949, we demonstrate that DGK α activity is required for 17-β-estradiol (E2)-induced proliferation, motility, and anchorage-independent growth of …
The COMT val158met Polymorphism Is Associated with Early Pubertal Development, Height and Cortical Bone Mass in Girls
2005
Estrogens are involved in accretion of bone mass during puberty. Catechol-O-Methyltransferase (COMT) is involved in the degradation of estrogens. In this cross-sectional study we investigated associations between the COMT val158met polymorphism, which results in a 60-75% difference in enzyme activity between the val (high activity = H) and the met (low activity = L) variant, and skeletal phenotypes in 246 healthy pre/early pubertal girls. Girls with COMT(LL) were 5.4 cm taller than COMT(HH) girls. Dual x-ray absorptiometry showed higher values of bone mineral content (BMC), and larger areas of total body, femur and spine in COMT(LL). Cortical BMC, measured by peripheral quantitative compute…
Effects of polymorphisms of the sex hormone-binding globulin (SHBG) gene on free estradiol and bone mineral density.
2009
Polymorphisms of the sex hormone-binding globulin (SHBG) gene are associated with differences in SHBG levels, influencing the risk for breast cancer and polycystic ovarian syndrome, but no association has been reported for osteoporosis in postmenopausal women.To determine the effect of G to A substitution in the 5'UTR (rs1799941) and the Asp356Asn (rs6259) polymorphisms of the SHBG gene on bone mineral density (BMD).This is a cross-sectional study in a university-based research center from May, 2002 to December, 2007. A total of two hundred and thirteen healthy postmenopausal Caucasian womenor = 1 year from last menstrual period participated to this study. Serum estradiol by ultrasensitive …
Change in bone mass distribution induced by hormone replacement therapy and high-impact physical exercise in post-menopausal women.
2002
The purpose of this intervention trial was to determine whether changes in bone mass distribution could be observed in postmenopausal women following hormone replacement therapy (HRT) and/or high-impact physical exercise. Eighty healthy women, aged 50-57 years, at5 years after the onset of menopause and with no previous use of HRT, were randomly assigned to one of four groups: HRT; exercise (Ex); HRT + Ex (ExHRT); and control (Co). HRT administration was conducted in a double-blind manner for 1 year using estradiol plus noretisterone acetate (Kliogest). The exercise groups participated in a 1 year progressive training program consisting of jumping and bounding activities. Subjects participa…
The effect of oral hormone replacement therapy on lipoprotein profile, resistance of LDL to oxidation and LDL particle size
2001
Abstract Objectives: To disclose if oral estradiol (E 2 ), alone or in combination with natural progesterone (P) or medroxyprogesterone acetate (MPA), may modify the oxidizability of low density lipoprotein (LDL), and if the effect is achieved at physiological dosages. LDL oxidizability was assessed by the resistance to oxidation by copper and by the particle size profile, since small particles have increased oxidation susceptibility. Methods: Thirty-three women received two consecutive, two-month length doses of 1 and 2 mg/day of oral E 2 . They were then randomly assigned to a fourteen-day treatment of 2 mg/day E 2 plus either 300 mg/day P or 5 mg/day MPA. A parallel group of experiments …
The estrogen receptor α:insulin receptor substrate 1 complex in breast cancer: structure–function relationships
2007
Background: Insulin receptor substrate 1 (IRS-1) is a signaling molecule that exerts a key role in mediating cross talk between estrogen receptor a (ERa) and insulin-like growth factor 1 (IGF-1) in breast cancer cells. Previously, we demonstrated that a fraction of IRS-1 binds ERa, translocates to the nucleus, and modulates ERa-dependent transcription at estrogen response elements (ERE). Here, we studied structure-function relationships of the ER-a:IRS-1 complex under IGF-1 and/or estradiol (E 2 ) stimulation. Materials and methods: ERa and IRS-1 deletion mutants were used to analyze structural and functional ERα/IRS-1 interactions. IRS-1 binding to ERE and IRS-1 role in ERa-dependent ERE t…
O069. Menstrual cycle affects cortical excitability differently in females with migraine and in healthy controls: a new perspective by cross modal so…
2015
The sound-induced flash illusions (SIFI) represent a valid tool to explore multimodal perception and are critically dependent on visual and acoustic cortical excitability [1, 2]. In a previous study [3], we observed a significant reduction of illusions in migraine patients with respect to healthy controls, probably due to a condition of visual cortex hyperexcitability. Aim of the present study was to evaluate SIFI perceptions in healthy women and patients with menstrual migraine and to describe the effects of cyclical change of steroid hormones and cortical responsiveness.
Viability and function of the cryopreserved whole rat ovary: comparison between slow-freezing and vitrification
2011
Objective To investigate four different protocols for cryopreservation of the whole rat ovary with intact vasculature to evaluate whether differences exist in post-thawing viability of the ovary after either vitrification or slow freezing. Design Experimental study. Setting Obstetrics and gynecology department. Animal(s) Immature Sprague-Dawley female rats. Intervention(s) Ovaries were isolated with the vascular tree intact up to the bifurcation of the abdominal aorta and were subsequently cannulated. The ovaries were flushed with increasing concentrations of the cryoprotectant dimethyl sulfoxide (DMSO) to either 1.5 or 7 M. The ovaries underwent cryopreservation by vitrification or passive…
Selective inhibition of calcium entry induced by benzylisoquinolines in rat smooth muscle.
1992
Abstract The mechanism of relaxant activity of six benzylisoquinolines was examined in order to determine the minimal structural requirements that enable these compounds to have either a non-specific action like papaverine or an inhibitory activity on calcium entry via potential-operated channels. All the alkaloids tested totally or partially relaxed KCl-depolarized rat uterus and inhibited oxytocin-induced rhythmic contractions. Only glaucine and laudanosine inhibited K+-induced uterine contractions more than oxytocin-induced uterine contractions. In Ca+-free medium, sustained contractions induced by oxytocin or vanadate were relaxed by the alkaloids tested except for glaucine and laudanos…
Early, but not late onset estrogen replacement therapy prevents oxidative stress and metabolic alterations caused by ovariectomy.
2014
Aims: The usefulness of estrogen replacement therapy (ERT) in preventing oxidative stress associated with menopause is controversial. We aimed to study if there is a critical time window for effective treatment of the effects of ovariectomy with estrogens at the molecular, metabolic, and cellular level. Results: Our main finding is that early, but not late onset of ERT prevents an ovariectomy-associated increase in mitochondrial hydrogen peroxide levels, oxidative damage to lipids and proteins, and a decrease in glutathione peroxidase and catalase activity in rats. This may be due to a change in the estrogen receptor (ER) expression profile: ovariectomy increases the ER α/β ratio and immedi…