Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Estrogen Receptor Modulators”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,567 records · Page 87Linked to original sources
PubMed2005

Effects of tibolone on bone quality in ovariectomized monkeys.

OBJECTIVE: The purpose of this report is to examine the effects of two doses of tibolone on bone quality (bone biomarkers, bone density, and bone strength) in ovariectomized cynomolgus monkeys fed high-fat diets. DESIGN: Ovariectomized cynomolgus monkeys were randomized into one of five treatment groups: placebo-treated control, tibolone (0.2 mg/kg/day), tibolone (0.05 mg/kg/day), conjugated equine estrogens (Premarin, 0.042 mg/kg/day), and conjugated equine estrogens plus medroxyprogesterone acetate (0.042 and 0.167 mg/kg/day, respectively). Bone quality was assessed by determining bone strength and density in vertebrae and femora collected after 24 months of treatment. RESULTS: Monkeys treated for 24 months with tibolone had increased bone mineral density in the distal femur and improved biomechanical properties in the midshaft femur compared with placebo-treated ovariectomized monkeys, as did monkeys treated with conjugated equine estrogens with or without medroxyprogesterone acetate. No treatment effects were seen in lumbar vertebra bone density or strength. There was no significant difference between tibolone and estrogen on biomechanical properties of the femur. CONCLUSION: These data show that tibolone is comparable to conjugated equine estrogens with or without medroxyprogesterone acetate in decreasing bone turnover and increasing bone strength in ovariectomized monkeys.

Alkaline Phosphatase↗
PubMedDate not supplied

Effects of tibolone on estrogen biosynthesis in the mammary tissue of postmenopausal monkeys.

OBJECTIVE: To evaluate the long-term effects of tibolone on estrone sulfate (E1S)-sulfatase activity in breast tissue in a primate model (Macaca fascicularis) in comparison with conventional hormone therapies. DESIGN: Ovariectomized female animals (n = 112) were randomized into five groups and treated for 2 years. Treatment included tibolone at 0.05 mg/kg (LoTib, n = 23) or 0.2 mg/kg (HiTib, n = 23), conjugated equine estrogens at 0.042 mg/kg (CEE, n = 24), CEE + medroxyprogesterone acetate at 0.167 mg/kg (CEE+MPA, n = 21), or placebo (controls, n = 21). E1S-sulfatase activity was evaluated by incubating homogenized breast tissue with [H]-E1S. Thin-layer chromatography was performed to separate the products estrone (E1) and estradiol (E2). Histomorphometry was performed to measure the amount of epithelial and fat tissue in the mammary gland. RESULTS: Significantly more E2 than E1 was produced in all groups. E1S-sulfatase activity did not differ among the groups. E1S-sulfatase activity was highest in HiTib animals with less fatty breasts (5.9 fmol total estrogen/mg of protein/min; P < or =0.05) and lowest in HiTib animals with more fatty breasts (2.8 fmol total estrogen/mg of protein/min; P = 0.004 relative to less fatty breasts). CONCLUSIONS: We conclude that tibolone had a differential effect on local estrogen biosynthesis in animals with high and low breast fat content. Therefore, breast tissue composition affects the steroidogenic response to hormonal treatment.

Animals↗
PubMedDate not supplied

Different effects of tibolone and low-dose EPT in the management of postmenopausal women with primary headaches.

OBJECTIVE: The present randomized prospective study aimed to compare the effect of tibolone (T) with conventional low-dose estrogen-progestogen therapy (EPT) administered in a combined continuous regimen on the course of primary headaches in postmenopausal women requesting hormone therapy (HT) for climacteric complaints. DESIGN: Forty women presenting for clinical evaluation of headache (migraine without aura and episodic tension-type headache) were enrolled. The observational period lasted 7 months during which women kept a diary of the clinical characteristics of headache attacks and analgesic use. Climacteric symptoms and both anxiety and depression were also measured. After a 1-month run-in period, women received two different HT regimens: 1 mg 17beta-estradiol + 0.5 mg norethisterone acetate (EPT) or 2.5 mg T. Follow-up evaluations were planned after 3 and 6 months of treatment. RESULTS: Although T did not affect the number of days with migraine without aura, it significantly reduced the number of hours during which pain intensity prohibited daily activities (P < 0.001) and the number of analgesics (P < 0.001) after 3 months. Conventional low-dose EPT administered in a combined continuous regimen was confirmed to have a mild, but negative, effect on the course of migraine without aura by increasing the number of days with head pain (P < 0.001) and the number of analgesics (P < 0.001). Interestingly, both treatments were effective in the management of episodic tension-type headache, significantly reducing the number of days with head pain, severity, and analgesic consumption. CONCLUSIONS: In postmenopausal headache sufferers, analgesics are more effective in alleviating severe head pain when women are treated with T in comparison with low-dose EPT for climacteric complaints.

Analysis of Variance↗
PubMed2004

Tibolone.

Explore the source record for details and available documents.

Abnormalities, Drug-Induced↗
PubMed2006

Dynamic changes in dopaminergic neurotransmission induced by a low concentration of bisphenol-A in neurones and astrocytes.

One of the most common chemicals that behaves as an endocrine disruptor is the compound 4,4'-isopronylidenediphenol, called bisphenol-A (BPA). We previously reported that prenatal and postnatal exposure to BPA potentiated central dopaminergic neurotransmission, resulting in supersensitivity to psychostimulant-induced pharmacological actions. Many recent findings have supported the idea that astrocytes, which are a subpopulation of glial cells, play a critical role in neuronal transmission in the central nervous system. The present study aimed to investigate the role of neurone-astrocyte communication in the enhancement of dopaminergic neurotransmission induced by BPA. We found that treatment of mouse purified astrocytes and neurone/glia cocultures with BPA in vitro caused the activation of astrocytes, as detected by a stellate morphology and an increase in levels of glial fibrillary acidic protein. A low concentration of BPA significantly enhanced the Ca2+ responses to dopamine in both neurones and astrocytes. Furthermore, a high concentration of BPA markedly induced the activation of caspase-3, which is a marker of neuronal apoptotic cell death in mouse midbrain neurone/glia cocultures. By contrast, treatment with 17beta-oestradiol (E2) had no such effects. Prenatal and neonatal exposure to BPA led to an enhancement of the dopamine-dependent rewarding effect induced by morphine. These findings provide evidence that BPA alters dopamine responsiveness in neurones and astrocytes and that, at least in part, it may contribute to potentiate the development of psychological dependence on drugs of abuse.

Analgesics, Opioid↗
PubMed2006

Effects of long-term hormone treatment and of tibolone on monoamines and monoamine metabolites in the brains of ovariectomised, Cynomologous monkeys.

The effects of long-term hormone treatment on monoamines and monoamine metabolites in different regions of the primate brain were examined and compared. Ovariectomised Cynomologous monkeys received daily oral administration of either conjugated equine oestrogens (CEE), CEE + medroxyprogesterone acetate (MPA), or a low or high dose of tibolone, for a period of 2 years. Tissue punches collected from frozen sections through various regions of the forebrain, midbrain, and hindbrain were assayed for levels of dopamine, dihydroxyphenylacetic acid (DOPAC), serotonin, 5-hydroxyindole acetic acid (5-HIAA), and norepinephrine by high-performance liquid chromatography. Few differences between hormone-treated animals and ovariectomised controls were observed. No statistically significant effects of CEE relative to controls were detected in any of the seven brain regions analysed. Animals treated with CEE + MPA showed significant reductions in 5-HIAA in the dorsal raphe nucleus, a significant reduction in dopamine in the hypothalamus, and a significant reduction in serotonin (5-HT) levels in area 8AD of the frontal cortex. Similar to CEE, no significant effects of tibolone relative to controls were detected; however, animals treated with high-dose tibolone showed a decrease in 5-HT levels in the frontal cortex that approached significance and was similar to the effect of CEE + MPA. Collectively, the findings suggest that long-term oral administration of these compounds has relatively few effects on the levels of dopamine, serotonin, and their primary metabolites in the primate brain. This differs from the significant effects on serotonergic and dopaminergic systems detected following parenteral treatment with oestradiol and progesterone, and likely reflects differences between the effects of treating with CEE + MPA versus oestradiol and progesterone on brain monoaminergic systems.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2002

Effects of tibolone and continuous combined hormone replacement therapy on bleeding rates, quality of life and tolerability in postmenopausal women.

OBJECTIVE: To compare the effects of tibolone and conjugated equine oestrogens continuously combined with medroxyprogesterone acetate on bleeding rates, quality of life (QoL) and tolerability. DESIGN: A double-blind, randomised comparative trial. SETTING: Thirty-seven centres in six European countries. POPULATION: Five hundred and one postmenopausal women, under 65 years of age with an intact uterus. INTERVENTIONS: For 12 months, women received daily treatment with tibolone 2.5 mg (n = 250), or conjugated equine oestrogens 0.625 mg continuously combined with medroxyprogesterone acetate 5 mg (CEE-MPA, n = 251). MAIN OUTCOME MEASURES: The primary outcome was vaginal bleeding rate during cycles 4-6. The secondary outcomes were vaginal bleeding rate during cycles 1-3, 7-9 and 10-13, cumulative bleeding rate, QoL, wellbeing, climacteric symptoms, urogenital complaints and tolerability. RESULTS: Treatment with tibolone led to a significantly lower bleeding rate during cycles 4-6 compared with CEE-MPA (15.0% vs 26.9%; P = 0.004); there was a similar difference during cycles 1-3. Both treatments improved QoL, wellbeing, climacteric symptoms and urogenital complaints. By intent-to-treat analysis, tibolone significantly improved sexual drive, interest and/or performance, compared with CEE-MPA at 12 months (P = 0.017). Although both treatments were well tolerated, there was a significantly lower incidence of breast tenderness with tibolone than CEE-MPA (2.4% vs 17.1%; P < 0.001). CONCLUSION: The vaginal bleeding rate during cycles 4-6 was significantly lower in women using tibolone. Both treatments improved QoL, wellbeing, climacteric symptoms and urogenital symptoms. Breast tenderness was significantly less frequent with tibolone.

Drug Combinations↗
PubMed2005

Assessment and management of women's sexual dysfunctions: problematic desire and arousal.

INTRODUCTION: Women frequently report low sexual desire or interest. An associated lack of subjective arousal during sexual activity is clinically highly apparent but has not been the focus of traditional sexual inquiry, definitions of dysfunction, or management. The frequent poor correlation of women's subjective sexual arousal and observable increases in genital congestion in response to sexual stimulation has not been reflected in assessment, diagnosis, or management. AIM: To provide recommendations/guidelines for the assessment and management of women's sexual dysfunctions focusing on low desire, low interest, and lack of arousal. METHODS: An international consultation, in collaboration with major sexual medicine associations, assembled over 200 multidisciplinary experts from 60 countries into 17 committees. One subcommittee of five members focused on women's sexual desire and arousal, developing over a 2-year period various recommendations. MAIN OUTCOME MEASURE: Expert opinion was based on grading of evidence-based scientific literature, widespread internal committee discussion, public presentation, and debate. RESULTS: Women's sexual response in health can be reconceptualized as a circular model of overlapping phases of variable order influenced by psychological, societal, and biological factors. Subsequent revisions to definitions of arousal and desire disorder are given. Recommendations regarding assessment and management focus on factors reducing arousability and satisfaction. These include women's mental health and feelings for their partner, generally and at the time of sexual activity. Recommendations reflect the poor correlation of subjective arousal and increases in genital vasocongestion. CONCLUSION: Further outcome research of management based on new conceptualization of sexual response and revised definitions of dysfunction is needed. The basis of the variable correlation between genital vasocongestion and subjective arousal needs clarification as do the biological underpinnings of sexual response and their changes with age and life cycle.

Adult↗
PubMed2005

Inhibitory effects of idoxifene on hepatic fibrosis in rats.

AIM: To investigate the effects of a tissue-specific selective estrogen receptor modulator, idoxifene, on hepatic fibrosis in rats. METHODS: Hepatic fibrosis was induced by dimethylnitrosamine (DMN) in male rats. The DMN model of hepatic fibrosis and the hepatocytes undergoing oxidative stress were treated with idoxifene respectively. The effect of idoxifene on hepatic fibrosis in the DMN model was examined by immunohistochemistry. Effects of idoxifene on antioxidant enzyme levels of copper, zinc-dependent superoxide dismutase (CuZn-SOD), and cellular glutathione peroxidase (GSHPx) were measured by ELISA. Effects of idoxifene on activation, proliferation, and apoptosis of culture-activated hepatic stellate cells (HSC) were analysed by immunohistochemistry, bromodeoxyuridine (BrdU) uptake, and flow cytometry, respectively. RESULTS: Idoxifene could markedly suppress DMN-induced hepatic fibrosis in male rats. A treatment of 0.4 mg x kg(-1) x d(-1) of idoxifene reduced the protein levels of collagen in the DMN model by 41.19% (P<0.05). Protein level of CuZn-SOD and activitiy of GSHPx in liver treated with DMN plus 0.4 mg/kg/d of idoxifene were 2.65 times (P<0.05) and 2.08 times greater (P<0.05) than that of liver treated with DMN alone respectively. The protein level of CuZn-SOD and activity of GSHPx in cultured rat hepatocytes treated with ferric nitrilotriacetate (FeNTA) plus 1 multiply 10(-7) mol/L of idoxifene were 3.43 times (P<0.05) and 2.52 times (P<0.05) greater than that treated with FeNTA alone. Idoxifene could inhibit HSC activation. Compared with the control, the uptake of BrdU in HSC cultured with 1 multiply 10(-7) mol/L of idoxifene was reduced by 51.87 % (P<0.05), and the number of apoptotic HSCs cultured with 1 multiply 10(-7) mol/L of idoxifene increased by 94.52% (P<0.05). CONCLUSION: Idoxifene showed inhibitory action on hepatic fibrosis in male rats.

Animals↗
PubMed2006

Neuroprotective effects of 17beta-estradiol and nonfeminizing estrogens against H2O2 toxicity in human neuroblastoma SK-N-SH cells.

Neuroprotective effects of estrogens have been shown in various in vitro and in vivo models, but the mechanisms underlying protection by estrogen are not clear. Mounting evidence suggests antioxidant effects contribute to the neuroprotective effects of estrogens. In the present study, we assessed the protective effects of estrogens against H2O2-induced toxicity in human neuroblastoma cells and the potential mechanisms involved in this protection. We demonstrate that 17beta-estradiol (17beta-E2) increases cell survival against H2O2 toxicity in human neuroblastoma cells. 17beta-E2 effectively reduced lipid peroxidation induced by 5-min H2O2 exposure. Furthermore, 17beta-E2 exerts the protective effects by maintaining intracellular Ca2+ homeostasis, attenuating ATP depletion, ablating mitochondrial calcium overloading, and preserving mitochondrial membrane potential. Two nonfeminizing estrogens, 17alpha- and ent-estradiol, were as effective as 17beta-E2 in increasing cell survival, alleviating lipid peroxidation, preserving mitochondrial function, and maintaining intracellular glutathione levels and Ca2+ homeostasis against H2O2 insult. Moreover, the estrogen receptor antagonist fulvestrant (ICI 182,780) did not block effects of 17beta-E2, but increased cell survival and blunted intracellular Ca2+ increases. However, these estrogens failed to reduce cytosolic reactive oxygen species, even at concentrations as high as 10 microM. In conclusion, estrogens exert protective effects against oxidative stress by inhibiting lipid peroxidation and subsequently preserving Ca2+ homeostasis, mitochondrial membrane potential, and ATP levels.

Calcium↗
PubMed2000

Therapeutic approaches to bone diseases.

The strength and integrity of our bones depends on maintaining a delicate balance between bone resorption by osteoclasts and bone formation by osteoblasts. As we age or as a result of disease, this delicate balancing act becomes tipped in favor of osteoclasts so that bone resorption exceeds bone formation, rendering bones brittle and prone to fracture. A better understanding of the biology of osteoclasts and osteoblasts is providing opportunities for developing therapeutics to treat diseases of bone. Drugs that inhibit the formation or activity of osteoclasts are valuable for treating osteoporosis, Paget's disease, and inflammation of bone associated with rheumatoid arthritis or periodontal disease. Far less attention has been paid to promoting bone formation with, for example, growth factors or hormones, an approach that would be a valuable adjunct therapy for patients receiving inhibitors of bone resorption.

Animals↗
PubMed2002

Glycolysis as a metabolic marker in orthotopic breast cancer, monitored by in vivo (13)C MRS.

Enhanced glycolysis represents a striking feature of cancers and can therefore serve to indicate a malignant transformation. We have developed a noninvasive, quantitative method to characterize tumor glycolysis by monitoring (13)C-labeled glucose and lactate with magnetic resonance spectroscopy. This method was applied in MCF7 human breast cancer implanted in the mammary gland of female CD1-NU mice and was further employed to assess tumor response to hormonal manipulation with the antiestrogen tamoxifen. Analysis of the kinetic data based on a unique physiological-metabolic model yielded the rate parameters of glycolysis, glucose perfusion, and lactate clearance in the tumor, as well as glucose pharmacokinetics in the plasma. Treatment with tamoxifen induced a twofold reduction in the rate of glycolysis and of lactate clearance but did not affect the other parameters. This metabolic monitoring can thus serve to evaluate the efficacy of new selective estrogen receptor modulators and may be further extended to improve diagnosis and prognosis of breast cancer.

Animals↗
PubMed2005

Differential effects of 17beta-estradiol and raloxifene on VSMC phenotype and expression of osteoblast-associated proteins.

Several studies demonstrate an association between osteoporosis and arterial calcific disease, both of which being common in elderly women. Estradiol and raloxifene, a selective estrogen receptor modulator, prevent bone loss in postmenopausal women. Little is known regarding how these agents affect arterial calcification. The aim of this study was to determine whether or not 17beta-estradiol and raloxifene reduced vascular smooth muscle cell (VSMC) differentiation and expression of bone-associated proteins during phosphate-induced calcification in vitro. Aortic VSMC were cultured from adult, gonadally intact, and ovariectomized (OVX) female pigs. Calcifying medium was added, and cells were treated with solvent (control), 17beta-estradiol (E(2)), or raloxifene. Extent of calcification and phenotypic expression of bone-associated proteins [matrix gla protein (MGP), osteoprotegerin (OPG), and bone sialoprotein (BSP)] were examined at 3-day intervals over 2 wk. Calcium content increased in all groups but was greater in VSMC derived from intact compared with OVX animals. E(2) reduced calcification and preserved a contractile phenotype. Expression of OPG significantly decreased with time; this decrease was significantly greater in VSMC derived from OVX compared with gonadally intact pigs. E(2) and raloxifene preserved expression of OPG only in VSMC from intact pigs. Expression of MGP increased significantly with time and was not affected by E(2) or raloxifene treatments. E(2) treatment significantly inhibited synthesis of BSP in cells from both groups. In conclusion, E(2) slows differentiation of VSMC induced by excess phosphate. Effectiveness of raloxifene to preserve expression of bone cell-associated proteins depends on the hormonal status of the tissue donor.

Animals↗
PubMed2005

[Prevalence of osteopenia and osteoporosis in postmenopausal women].

OBJECTIVE: To know the osteoponia and osteoporosis prevalence in postmenopausal women determined with broadband ultrasonic attenuation (BUA). DESIGN: Descriptives cross-sectional study of prevalence. SETTING: Salvador Allende Health Center. Valencia, Spain. PARTICIPANTS: A total of 115 postmenopausal women aged 49 at 85 years old was studied, initiated in September to December 2003. Iatrogenic menopause or women with calcium, vitamin D, estrogen replacement therapy, estrogen receptor modulators, and biphosphonates therapy were considered criteria for exclusion. We measured bone mineral density with BUA at right calcaneus. MAIN MEASUREMENTS: We analyzed the age, height, and weight, the result of BUA, tobacco and diuretics consumption and years of amenorrhea. RESULTS: . The prevalence of osteoporosis was 50.4%. Other 29.6% had osteopenia. Of the postmenopausal women with osteoporosis, 27.6% were 70 to 75 years old. The 82.8% of postmenopausal women with osteoporosis were younger than 75 years old. The 66.7% postmenopausal women with body mass index lesser than 25 had osteoporosis. CONCLUSIONS: The osteoporosis prevalence in our patients was greater than other studies (30%). Emphasis may be placed on screening osteoporosis with BUA in primary health care. We suggested that educational community programs should start at an earlier age to identify factors that contribute to maintaining bone mineral density among postmenopausal women.

Aged↗
PubMed2006

Treatment-related osteoporosis in men with prostate cancer.

The intended therapeutic effect of gonadotropin-releasing hormone (GnRH) agonists is hypogonadism, a major cause of acquired osteoporosis in men. Consistent with this observation, GnRH agonists increase bone turnover and decrease bone mineral density, a surrogate for fracture risk. Large claims-based analyses and other retrospective studies provide compelling evidence that GnRH agonists increase risk of clinical fractures. Estrogens play a central role in homeostasis of the normal male skeleton, and estrogen deficiency rather than testosterone deficiency seems to be primarily responsible for the adverse skeletal effects of GnRH agonists. In randomized controlled trials, bisphosphonates (pamidronate and zoledronic acid) and selective estrogen receptor modulators (raloxifene and toremifene) increased bone mineral density in GnRH agonist-treated men. Two ongoing large randomized placebo-controlled studies will prospectively define fracture outcomes in men with prostate cancer and assess the efficacy of novel pharmacologic interventions (AMG162, toremifene) during GnRH agonist treatment.

Antineoplastic Agents↗
PubMed2002

Effects of tibolone on thromboxane B(2) levels in postmenopausal women.

This study was carried out in 16 premenopausal (control) and 24 postmenopausal women (study group) to investigate the effect of menopause and tibolone treatment (2.5 mg/day for 6 months) on plasma thromboxane B(2) (TxB(2)), a well-known vasoconstrictor and stimulator of platelet aggregation. The TxB(2) levels were measured using [(125)I] RIA kit. Statistical significance was analyzed by Student's t test for paired and unpaired data, and Pearson's correlation analysis. Plasma TxB(2) concentrations of postmenopausal women were higher than those of premenopausal women. Tibolone treatment decreased plasma TxB(2) in postmenopausal women. There was no correlation between TxB(2) and blood pressure and heart rate. It was concluded that tibolone, decreasing the plasma concentrations of TxB(2), might have beneficial effects on prostaglandin metabolism and thus reduce the risk of cardiovascular disease.

Adult↗
PubMed1999

Can an autocrine loop explain sex-hormone-dependent tumor growth? A brief overview.

Sex hormones and their related compounds have been known to regulate the target cell growth positively or negatively in the receptor-dependent manner. The molecular mechanism of these complicated events, especially sex hormone-dependent growth enhancement, has been studied extensively. In MCF-7 cells, estrogen-induced autocrine loop has been demonstrated to play the important role for estrogen-dependent growth. Androgen has been also found to promote the growth of SC-3 cell through the induction of an autocrine growth factor (FGF 8). The blockade of FGF 8 activity resulted in a complete inhibition of androgen-dependent growth of SC-3 cells, suggesting that FGF 8 acts as an essential component of androgen-dependent growth. However, the constitutional expression of FGF 8 failed to convert SC-3 cells from an androgen-dependent to an androgen-independent phenotype. These observations would suggest that sex hormone-induced autocrine loop is an obligatory but not sufficient component for the growth of sex hormone-dependent tumor.

Androgens↗
PubMed1999

Mitogen-activated protein kinase cascade in breast cancer.

The mitogen-activated protein (MAP) kinase is considered to play a central role in diverse cellular events including carcinogenesis and tumor progression. Indeed, expression of MAP kinase, tyrosine-phosphorylated MAP kinase, and Raf-1 protein was greater in cancerous human tissues than in the surrounding noncancerous glands. In a 7,12-dimethylbenz[a]anthracene-induced rat mammary carcinoma model, estrogen promoted and ovariectomy and antiestrogen, tamoxifen (TAM) inhibited the tumor growth. Ovariectomy suppressed expression of MAP kinase, tyrosine-phosphorylated MAP kinase and Raf-1, whereas estrogen as well as TAM induced expression of MAP kinase and Raf-1 under castrated conditions. Since it was reported that MAP kinase was activated during the progression of breast carcinoma cells, such estrogenic actions of TAM toward the MAP kinase cascade might be responsible for malignant progression.

Animals↗