RESUMEN
This study evaluated the protective effect of proanthocyanidins (PCs) on reducing apoptosis in the mouse intestinal epithelial cell model MODE-K exposed to zearalenone (ZEA) through inhibition of the endoplasmic reticulum stress (ERS)-induced apoptosis pathway. Our results showed that PCs could reduce the rate of apoptosis in MODE-K cells exposed to ZEA (p < 0.01). PCs significantly increased the ZEA-induced antioxidant protective effects on the enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and on the content of GSH. PCs also significantly decreased the ZEA-induced increase in the content of malondialdehyde (MDA). The analysis indicated that ZEA increased both mRNA and protein expression levels of C/EBP homologous protein (CHOP), GRP78, c-Jun N-terminal kinase (JNK), and cysteinyl aspartate specific proteinase 12 (caspase-12) (p < 0.05), which are related to the ERS-induced apoptosis pathway. ZEA decreased levels of the pro-apoptotic related protein Bcl-2 (p < 0.05) and increased the anti-apoptotic related protein Bax (p < 0.05). Co-treatment with PCs was also shown to significantly reverse the expression levels of these proteins in MODE-K cells. The results demonstrated that PCs could protect MODE-K cells from oxidative stress and apoptosis induced by ZEA. The underlying mechanism may be that PCs can alleviate apoptosis in mouse intestinal epithelial cells by inhibition of the ERS-induced apoptosis pathway.
Asunto(s)
Antioxidantes/farmacología , Estrés del Retículo Endoplásmico/efectos de los fármacos , Células Epiteliales/efectos de los fármacos , Estrógenos no Esteroides/antagonistas & inhibidores , Proantocianidinas/farmacología , Zearalenona/antagonistas & inhibidores , Animales , Apoptosis/efectos de los fármacos , Caspasa 12/genética , Caspasa 12/metabolismo , Línea Celular , Supervivencia Celular/efectos de los fármacos , Chaperón BiP del Retículo Endoplásmico , Células Epiteliales/citología , Células Epiteliales/metabolismo , Estrógenos no Esteroides/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Glutatión/agonistas , Glutatión/antagonistas & inhibidores , Glutatión/metabolismo , Glutatión Peroxidasa/genética , Glutatión Peroxidasa/metabolismo , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Intestino Delgado/citología , Intestino Delgado/efectos de los fármacos , Intestino Delgado/metabolismo , Proteínas Quinasas JNK Activadas por Mitógenos/genética , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Malondialdehído/agonistas , Malondialdehído/antagonistas & inhibidores , Malondialdehído/metabolismo , Ratones , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Transducción de Señal , Superóxido Dismutasa/genética , Superóxido Dismutasa/metabolismo , Factor de Transcripción CHOP/genética , Factor de Transcripción CHOP/metabolismo , Zearalenona/farmacología , Proteína X Asociada a bcl-2/genética , Proteína X Asociada a bcl-2/metabolismoRESUMEN
Estrogen regulates numerous developmental and physiological processes and effects are mediated mainly by estrogenic receptors (ERs), which function as ligand-regulated transcription factor. ERs can be activated by many different types endocrine disrupting chemicals (EDCs) and interfere with behaviour and reproductive potential of living organism. Estrogenic regulation of membrane associated G protein-coupled estrogen receptor, GPER activity has also been reported. Bisphenol A (BPA), a ubiquitous endocrine disruptor is present in many household products, has been linked to many adverse effect on sexual development and reproductive potential of wild life species. The present work is aimed to elucidate how an environmentally pervasive chemical BPA affects in vivo expression of a known estrogen target gene, cyp19a1b in the brain, and a known estrogenic biomarker, vitellogenin (Vg) in the whole body homogenate of 30â¯days post fertilization (dpf) swim-up fry of Labeo rohita. We confirm that, like estrogen, the xenoestrogen BPA exposure for 5-15â¯days induces strong overexpression of cyp19a1b, but not cyp19a1a mRNA in the brain and increase concentration of vitellogenin in swim-up fry. BPA also induces strong overexpression of aromatase B protein and aromatase activity in brain. Experiments using selective modulators of classical ERs and GPER argue that this induction is largely through nuclear ERs, not through GPER. Thus, BPA has the potential to elevate the levels of aromatase and thereby, levels of endogenous estrogen in developing brain. These results indicate that L. rohita swim-up fry can be used to detect environmental endocrine disruptors either using cyp19a1b gene expression or vitellogenin induction.
Asunto(s)
Aromatasa/metabolismo , Compuestos de Bencidrilo/toxicidad , Encéfalo/efectos de los fármacos , Cyprinidae/fisiología , Inductores de las Enzimas del Citocromo P-450/toxicidad , Disruptores Endocrinos/toxicidad , Neuronas/efectos de los fármacos , Fenoles/toxicidad , Animales , Acuicultura , Aromatasa/química , Aromatasa/genética , Compuestos de Bencidrilo/antagonistas & inhibidores , Encéfalo/enzimología , Encéfalo/crecimiento & desarrollo , Cyprinidae/crecimiento & desarrollo , Disruptores Endocrinos/química , Biomarcadores Ambientales/efectos de los fármacos , Inducción Enzimática/efectos de los fármacos , Antagonistas del Receptor de Estrógeno/farmacología , Estrógenos no Esteroides/antagonistas & inhibidores , Estrógenos no Esteroides/toxicidad , Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/metabolismo , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Neurogénesis/efectos de los fármacos , Neuronas/enzimología , Concentración Osmolar , Fenoles/antagonistas & inhibidores , ARN Mensajero/metabolismo , Regulación hacia Arriba/efectos de los fármacos , Vitelogeninas/agonistas , Vitelogeninas/genética , Vitelogeninas/metabolismo , Contaminantes Químicos del Agua/antagonistas & inhibidores , Contaminantes Químicos del Agua/toxicidadRESUMEN
Bisphenol A (BPA) is one hormonally active chemical with potential deleterious effects on reproductive organs, including breast and prostate. In contrast, genistein (GEN) is the major phytoestrogen of soy that presents potential protective effects against hormone-dependent cancers, including that of the prostate. Thus, pregnant Sprague-Dawley rats were treated with BPA at 25 or 250 µg/kg/day by gavage from gestational day (GD) 10-21 with or without dietary GEN at 250 mg/kg/chow (â¼5.5 mg/kg/day). Then, male offspring from different litters were euthanized on post-natal day (PND) 21 and 180. At PND21, BPA 25 exposure induced early prostatic changes while dietary GEN attenuated some deleterious actions this xenoestrogen on epithelial cell proliferation levels, androgen receptor expression and prostatic architecture in male offspring. At PND180, a significant increase in incidence of prostatic multifocal inflammation/reactive hyperplasia and atypical hyperplasia were observed in male offspring from dams that received BPA 25. On the other hand, maternal GEN feeding attenuated some the adverse effects of BPA 25 on prostate disease at late-in-life. This way, the present findings point to preventive action of dietary GEN on deleterious effects of gestational BPA exposure in both early and late prostate development in offspring F1.
Asunto(s)
Suplementos Dietéticos , Estrógenos no Esteroides/antagonistas & inhibidores , Genisteína/uso terapéutico , Fenómenos Fisiologicos Nutricionales Maternos , Fitoestrógenos/uso terapéutico , Efectos Tardíos de la Exposición Prenatal/prevención & control , Próstata/efectos de los fármacos , Animales , Compuestos de Bencidrilo/administración & dosificación , Compuestos de Bencidrilo/antagonistas & inhibidores , Compuestos de Bencidrilo/toxicidad , Proliferación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Estrógenos no Esteroides/administración & dosificación , Estrógenos no Esteroides/toxicidad , Femenino , Masculino , Fenoles/administración & dosificación , Fenoles/antagonistas & inhibidores , Fenoles/toxicidad , Embarazo , Efectos Tardíos de la Exposición Prenatal/metabolismo , Efectos Tardíos de la Exposición Prenatal/patología , Efectos Tardíos de la Exposición Prenatal/fisiopatología , Próstata/metabolismo , Próstata/patología , Hiperplasia Prostática/inducido químicamente , Hiperplasia Prostática/metabolismo , Hiperplasia Prostática/patología , Hiperplasia Prostática/prevención & control , Neoplasias de la Próstata/inducido químicamente , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/prevención & control , Ratas Sprague-Dawley , Receptores Androgénicos/metabolismo , Organismos Libres de Patógenos Específicos , DesteteRESUMEN
Developing reagents with high affinity and specificity are critical to detect the environmental hormones or toxicants. Ribosome display technology has been widely used in functional protein or peptide screening and in directed evolution of protein molecules in vitro. In this study, single-chain variable fragments (scFvs) against bisphenol A (BPA) were selected from a library constructed from splenocytes of non-immunized mice. After five rounds of selection, the selected scFvs bound to BPA with high affinity. Indirect competitive enzyme-linked immunosorbent assay (ELISA) was introduced to screen the antibody affinity and specificity to BPA. The equilibrium dissociation constants (KDS) of one clone was 1.76µM as determined by surface plasmon resonance (SPR). This study indicated that ribosome display can isolate binders to small molecules from a non-immunized naive library without any in vivo steps and can generate recombinant antibodies efficiently and rapidly. In addition, this study provides a methodological framework for detection of small molecules using recombinant antibodies.
Asunto(s)
Compuestos de Bencidrilo/análisis , Contaminantes Ambientales/análisis , Estrógenos no Esteroides/análisis , Fenoles/análisis , Ribosomas/metabolismo , Anticuerpos de Cadena Única/análisis , Secuencia de Aminoácidos , Animales , Afinidad de Anticuerpos , Especificidad de Anticuerpos , Compuestos de Bencidrilo/antagonistas & inhibidores , Compuestos de Bencidrilo/química , Compuestos de Bencidrilo/metabolismo , China , Contaminantes Ambientales/antagonistas & inhibidores , Contaminantes Ambientales/metabolismo , Ensayo de Inmunoadsorción Enzimática , Escherichia coli/enzimología , Escherichia coli/metabolismo , Estrógenos no Esteroides/antagonistas & inhibidores , Estrógenos no Esteroides/metabolismo , Biblioteca de Genes , Haptenos/análisis , Haptenos/química , Haptenos/metabolismo , Proteínas Inmovilizadas/química , Ligandos , Ratones , Datos de Secuencia Molecular , Fenoles/antagonistas & inhibidores , Fenoles/química , Fenoles/metabolismo , Proteínas Recombinantes/análisis , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Alineación de Secuencia , Anticuerpos de Cadena Única/química , Anticuerpos de Cadena Única/genética , Anticuerpos de Cadena Única/metabolismo , Bazo/metabolismo , Resonancia por Plasmón de SuperficieRESUMEN
Zearalenone (ZEN) has caused significant economic effects on swine production in China. There is growing concern that exposure to ZEN during pregnancy affects the health of the offspring due to changes in the development of the immune system. To assess the risks associated with maternal ZEN exposure, several immunological parameters were assessed in pregnant sows and their offspring. The main aim of the study was to determine if modified hallosite nanotubes (MHNTs) can be used to protect pigs against the adverse effects of ZEN. Eighteen pregnant sows (second parity Yorkshire sows) were randomly divided into three treatment groups: (1) basal diet (control group); (2) contaminated grain (instead of 50% mouldy corn); and (3) contaminated grain (instead of 50% mouldy corn) + 1% MHNTs. The pregnant sows were fed the different treated diets from days 35 to 70 of gestation. Dietary ZEN exposure decreased the organ coefficient and the mRNA expression levels of IFN-γ, TNF-α, and IL-10, and increased ZEN residues and IL-4 mRNA expression in the spleen of pregnant sows and neonatal piglets. Decreases in the serum IgA and IgG levels were observed in the pregnant sows. Maternal ZEN exposure decreased the organ coefficient and the mRNA expression levels of IFN-γ and IL-10, and increased IL-4 mRNA expression in the spleen of weaning piglets. Exposure to ZEN during pregnancy decreased the level of serum IgG in the weaning piglets. Maternal exposure to ZEN induced histopathological damage and oxidative stress in the spleens of pregnant sows and their piglets. The addition of MHNTs to ZEN-contaminated diets can mitigate the negative effects induced by ZEN in the swine.
Asunto(s)
Silicatos de Aluminio/farmacología , Estrógenos no Esteroides/antagonistas & inhibidores , Feto/efectos de los fármacos , Inmunidad Innata/efectos de los fármacos , Bazo/efectos de los fármacos , Zearalenona/antagonistas & inhibidores , Alimentación Animal , Animales , Arcilla , Estrógenos no Esteroides/efectos adversos , Femenino , Feto/inmunología , Expresión Génica/efectos de los fármacos , Edad Gestacional , Humanos , Inmunoglobulina A/sangre , Inmunoglobulina G/sangre , Interferón gamma/genética , Interferón gamma/inmunología , Interleucina-10/genética , Interleucina-10/inmunología , Interleucina-4/genética , Interleucina-4/inmunología , Nanotubos , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/inmunología , Embarazo , ARN Mensajero/genética , ARN Mensajero/inmunología , Bazo/inmunología , Porcinos , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/inmunología , Zearalenona/efectos adversosRESUMEN
The sequestration/inactivation of the oestrogenic mycotoxin zearalenone (ZEA) by two adsorbents--yeast cell wall extract (YCW) and hydrated sodium calcium aluminosilicate (HSCAS)--was studied in three laboratory models: (1) an in vitro model was adapted from referenced methods to test for the sequestrant sorption capabilities under buffer conditions at two pH values using liquid chromatography coupled to a fluorescence detector for toxin quantification; (2) a second in vitro model was used to evaluate the sequestrant sorption stability according to pH variations and using ³H-labelled ZEA at low toxin concentration; and (3) an original, ex vivo Ussing chamber model was developed to further understand the transfer of ZEA through intestinal tissue and the impact of each sequestrant on the mycotoxin bioavailability of ³H-labelled ZEA. YCW was a more efficient ZEA adsorbent than HSCAS in all three models, except under very acidic conditions (pH 2.5 or 3.0). The Ussing chamber model offered a novel, ex vivo, alternative method for understanding the effect of sequestrant on the bioavailability of ZEA. The results showed that compared with HSCAS, YCW was more efficient in sequestering ZEA and that it reduced the accumulation of ZEA in the intestinal tissue by 40% (p < 0.001).
Asunto(s)
Alimentación Animal , Productos Biológicos/metabolismo , Pared Celular/química , Estrógenos no Esteroides/antagonistas & inhibidores , Saccharomyces cerevisiae/química , Secuestrantes/metabolismo , Zearalenona/antagonistas & inhibidores , Silicatos de Aluminio/química , Silicatos de Aluminio/metabolismo , Animales , Productos Biológicos/química , Precipitación Química , Estrógenos no Esteroides/química , Estrógenos no Esteroides/metabolismo , Aditivos Alimentarios/química , Aditivos Alimentarios/metabolismo , Fármacos Gastrointestinales/química , Fármacos Gastrointestinales/metabolismo , Concentración de Iones de Hidrógeno , Íleon/metabolismo , Técnicas In Vitro , Absorción Intestinal , Mucosa Intestinal/metabolismo , Masculino , Ratas , Ratas Wistar , Secuestrantes/química , Solubilidad , Zearalenona/química , Zearalenona/metabolismoRESUMEN
Endocrine disrupting chemicals (EDCs) and estrogens appear to promote development of estrogen-dependent cancers, including breast and ovarian carcinomas. In this study, we evaluated the cell viability effect of BPA on BG-1 human ovarian cancer cells, along with the growth inhibitory effect of resveratrol (trans-3,4,5-trihydroxystilbene; RES), a naturally occurring phytoestrogen. In addition, we investigated the underlying mechanism(s) of BPA and RES in regulating the interaction between estrogen receptor alpha (ERα) and insulin-like growth factor-1 receptor (IGF-1R) signals, a non- genomic pathway induced by 17ß-estradiol (E2). BPA induced a significant increase in BG-1 cell growth and up-regulated mRNA levels of ERα and IGF-1R. In parallel with its mRNA level, the protein expression of ERα was induced, and phosphorylated insulin receptor substrate-1 (p-IRS-1), phosphorylated Akt1/2/3, and cyclin D1 were increased by BPA or E2. However, RES effectively reversed the BG-1 cell proliferation induced by E2 or BPA by inversely down-regulating the expressions of ERα, IGF-1R, p-IRS-1, and p-Akt1/2/3, and cyclin D1 at both transcriptional and translational levels. Taken together, these results suggest that RES is a novel candidate for prevention of tumor progression caused by EDCs, including BPA via effective inhibition of the cross-talk of ERα and IGF-1R signaling pathways.
Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Receptor alfa de Estrógeno/antagonistas & inhibidores , Neoplasias Ováricas/tratamiento farmacológico , Fitoestrógenos/farmacología , Receptor IGF Tipo 1/antagonistas & inhibidores , Transducción de Señal/efectos de los fármacos , Estilbenos/farmacología , Compuestos de Bencidrilo/antagonistas & inhibidores , Compuestos de Bencidrilo/farmacología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Ciclina D1/agonistas , Ciclina D1/antagonistas & inhibidores , Ciclina D1/genética , Ciclina D1/metabolismo , Regulación hacia Abajo/efectos de los fármacos , Estradiol/química , Estradiol/metabolismo , Receptor alfa de Estrógeno/agonistas , Receptor alfa de Estrógeno/genética , Receptor alfa de Estrógeno/metabolismo , Estrógenos no Esteroides/antagonistas & inhibidores , Estrógenos no Esteroides/farmacología , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Proteínas Sustrato del Receptor de Insulina/agonistas , Proteínas Sustrato del Receptor de Insulina/antagonistas & inhibidores , Proteínas Sustrato del Receptor de Insulina/genética , Proteínas Sustrato del Receptor de Insulina/metabolismo , Proteínas de Neoplasias/agonistas , Proteínas de Neoplasias/antagonistas & inhibidores , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Neoplasias Ováricas/metabolismo , Fenoles/antagonistas & inhibidores , Fenoles/farmacología , Fosforilación/efectos de los fármacos , Procesamiento Proteico-Postraduccional/efectos de los fármacos , Receptor IGF Tipo 1/agonistas , Receptor IGF Tipo 1/genética , Receptor IGF Tipo 1/metabolismo , ResveratrolRESUMEN
The fusarielins are a group of metabolites found in several Aspergillus and Fusarium species that have been reported to have with weak antifungal, antibiotic and cytotoxic effects. This study identifies fusarielin A, F, G and H isolated from Fusarium as mycoestrogens. Mycoestrogens are compounds from fungi that bind to the estrogen receptors and induce an estrogenic response in targeted cells. All four tested fusarielins stimulate MCF-7 cell proliferation with fusarielin H as the most potent, able to stimulate cell proliferation 4-fold in a resazurin metabolism assay at 25µM. MDA-MB-231 cells without the estrogen receptor-α and MCF-10a cells without estrogen receptors were not stimulated by fusarielins. Furthermore, the stimulation was prevented in MCF-7 cells when fusarielins were incubated in the presence of the estrogen receptor antagonist fulvestrant. These observations suggest that fusarielins bind to the estrogen receptor and act as weak mycoestrogens.
Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Anticarcinógenos/farmacología , Neoplasias de la Mama/tratamiento farmacológico , Compuestos Epoxi/farmacología , Estrógenos no Esteroides/farmacología , Proteínas Fúngicas/farmacología , Fusarium/química , Adenocarcinoma/metabolismo , Adenocarcinoma/patología , Anticarcinógenos/antagonistas & inhibidores , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Proliferación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Compuestos Epoxi/antagonistas & inhibidores , Estradiol/análogos & derivados , Estradiol/farmacología , Antagonistas de Estrógenos/farmacología , Estrógenos no Esteroides/antagonistas & inhibidores , Femenino , Fulvestrant , Humanos , Indicadores y Reactivos/farmacología , Células MCF-7 , Oxazinas/farmacología , Extractos Vegetales/antagonistas & inhibidores , Extractos Vegetales/farmacología , Receptores de Estrógenos/antagonistas & inhibidores , Receptores de Estrógenos/deficiencia , Receptores de Estrógenos/metabolismo , Xantenos/farmacologíaRESUMEN
Bisphenol-A (BPA), a toxic chemical from polycarbonate plastics, is known for behavioural and neural abnormalities. These neuro-behavioural changes reflect the changes in neural activity. However the effect of BPA on nerve action potential is not available. Therefore, present investigation was undertaken to study the effect of BPA on compound action potential (CAP) of frog sciatic nerve. Bundle containing small group of nerve fibres in a sciatic nerve was dissected and placed in a Perspex chamber perfused with Ringer solution. Suction electrodes were applied to the cut ends of the nerve for stimulating and recording purposes. The stimulation of one end (with supramaximal strength) produced CAP in the recording electrode. BPA (1-100 µM) decreased the amplitude and repolarization time of CAP in a concentration-dependent manner, without any alteration in latency, rise time and threshold. The decrease in amplitude was directly correlated with decrease in repolarization time (r=0.76). The BPA-induced decreases were absent in Ca(2+)-free medium or in presence of L-type Ca(2+)-channel antagonist (nifedipine/deltiazem). T and P type Ca(2+) channel antagonist (Ni(2+)) failed to block the BPA-induced responses. Pre-treatment with an Erα antagonist (tamoxifen) blocked the BPA-induced decrease in CAP parameters. These observations indicate that the BPA decreased the amplitude and repolarization time of CAP involving L-type Ca(2+)-channel dependent mechanisms. Further involvement of Erα in the modulation of Ca(2+) channels is a possibility.
Asunto(s)
Potenciales de Acción/efectos de los fármacos , Calcio/fisiología , Estrógenos no Esteroides/farmacología , Fenoles/farmacología , Nervio Ciático/efectos de los fármacos , Animales , Compuestos de Bencidrilo , Bloqueadores de los Canales de Calcio/farmacología , Diltiazem/farmacología , Estimulación Eléctrica , Electrodos , Fenómenos Electrofisiológicos , Antagonistas de Estrógenos/farmacología , Receptor alfa de Estrógeno/antagonistas & inhibidores , Estrógenos no Esteroides/antagonistas & inhibidores , Técnicas In Vitro , Níquel/farmacología , Nifedipino/farmacología , Fenoles/antagonistas & inhibidores , Ranidae , Tamoxifeno/farmacologíaRESUMEN
Cadmium (Cd) is a heavy metal classified as a human carcinogen. Occupational exposure, dietary consumption and cigarette smoking are sources of Cd contamination. Cd-induced carcinogenicity depends on its oxidative and estrogenic actions. A possible role of Cd in breast cancer etiology has been recently suggested. Melatonin, because of its antioxidant and antiestrogenic properties could counteract the toxic effects of this metalloestrogen. Our aim was both to determine the effects of relevant doses of Cd on mice mammary glands and uterus and to test whether melatonin would counteract its effects. Female mice of different ages and estrogenic status (prepuberal, adult intact, adult ovariectomized) were treated with CdCl(2) (2-3 mg/kg, i.p.), melatonin (10 microg/mL in drinking water), CdCl(2) + melatonin, or diluents. Whereas in prepuberal animals Cd disturbs mammary ductal growth and reduces the number of terminal end buds, in adults, regardless of the steroidal milieu, Cd exerts estrogenic effects on mammary glands, increasing lobuloalveolar development and ductal branching. Uterine weight also increased as a result of Cd treatment. The effects of Cd are partially inhibited by melatonin. In adult ovariectomized mice, Cd concentration in blood of animals treated with CdCl(2) + melatonin was lower than in mice receiving only Cd; the opposite effects were found in non-castrated animals. As Cd mimics the effect of estrogens, the high incidence of breast cancer in tobacco smokers and women working in industries related with Cd could be explained because of the properties of this metal. The effects of melatonin point to a possible role of this indoleamine as a preventive agent for environmental or occupational Cd contamination.
Asunto(s)
Cadmio/toxicidad , Glándulas Mamarias Animales/efectos de los fármacos , Melatonina/farmacología , Útero/efectos de los fármacos , Animales , Cadmio/antagonistas & inhibidores , Contaminantes Ambientales/antagonistas & inhibidores , Contaminantes Ambientales/toxicidad , Estrógenos no Esteroides/antagonistas & inhibidores , Estrógenos no Esteroides/toxicidad , Femenino , Humanos , Glándulas Mamarias Animales/patología , Ratones , Útero/patologíaRESUMEN
The mechanisms of diethylstilbestrol (1 to 30 microM)-induced relaxation on noradrenaline (30 nM)-raised tone in the rat aorta smooth muscle were studied. Neither the increase of calcium content in the medium (3, 6 and 9 mM) nor Bay K 8644 (3, 10 and 100 nM) reversed diethylstilbestrol relaxation. Tamoxifen (3 microM), the quaternary derivate (tamoxifen ethyl bromide, 3 microM), actinomycin D (30 microM), cycloheximide (100 microM), Rp-cAMPS (30 microM), TPCK (1 microM) and difluoromethylornithine (1 mM) inhibited diethylstilbestrol-induced relaxation. Incubation with 2 microg/ml pertussis toxin, propranolol (1 microM), H-7 (10 microM), 2',3'- and 2',5'-dideoxiadenosine (10 and 30 microM, respectively) and methylene blue (10 microM) did not modify diethylstilbestrol-induced relaxation. Our results showed that presumably an activation of membrane mechanisms, protein kinase A activation, genomic mechanisms and polyamine synthesis might participate in diethylstilbestrol-elicited relaxation in addition to the increase in K(ATP) permeability, as previously described. Actinomycin D produces a synergistic effect, with tamoxifen, difluoromethylornithine and glibenclamide antagonizing the effect of diethylstilbestrol. In the case of the association of actinomycin D and glibenclamide, the antagonism of relaxation is complete. The fact that tamoxifen- and difluoromethylornithine-dependent mechanisms participate in diethylstilbestrol relaxation inhibited by glibenclamide suggests that two transduction pathways are involved in the relaxation. Therefore, K(ATP) channels and genomic mechanisms, both modulated by cyclic AMP (cAMP)-dependent mechanisms, are associated with diethylstilbestrol relaxation.
Asunto(s)
Dietilestilbestrol/farmacología , Estrógenos no Esteroides/farmacología , Músculo Liso Vascular/efectos de los fármacos , Animales , Aorta Torácica/efectos de los fármacos , Proteínas Quinasas Dependientes de AMP Cíclico/antagonistas & inhibidores , Cicloheximida/farmacología , Dactinomicina/farmacología , Dietilestilbestrol/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Antagonistas de Estrógenos/farmacología , Estrógenos no Esteroides/antagonistas & inhibidores , Espacio Extracelular/efectos de los fármacos , Técnicas In Vitro , Masculino , Relajación Muscular/efectos de los fármacos , Tono Muscular/efectos de los fármacos , Norepinefrina/farmacología , Inhibidores de la Ornitina Descarboxilasa , Toxina del Pertussis/farmacología , Propranolol/farmacología , Proteína Quinasa C/antagonistas & inhibidores , Inhibidores de la Síntesis de la Proteína/farmacología , Ratas , Ratas Wistar , Sistemas de Mensajero Secundario/fisiología , Tamoxifeno/farmacología , Vasoconstrictores/farmacología , Vasodilatadores/farmacologíaRESUMEN
The alkyl esters of p-hydroxybenzoic acid (parabens) are used widely as preservatives in foods, pharmaceuticals and cosmetics to which the human population is exposed. Recent studies have reported that methylparaben, ethylparaben, n-propylparaben and n-butylparaben all possess oestrogenic activity in several in vitro assays and in animal models in vivo. This study reports on the oestrogenic activity of isobutylparaben in a panel of assays in vitro and in vivo. Isobutylparaben was able to displace [(3)H]oestradiol from cytosolic oestrogen receptor alpha of MCF7 human breast cancer cells by 81% at 100 000-fold molar excess. Using a clonal line of MCF7 cells containing a stably transfected oestrogen-responsive ERE-CAT reporter gene, CAT gene expression could be increased by isobutylparaben such that the magnitude of the response was the same at 10(-5) M isobutylparaben as with 10(-8) M 17beta-oestradiol. Isobutylparaben could also increase expression of the endogenous oestrogen-responsive pS2 gene in MCF7 cells and maximal expression at 10(-5) M isobutylparaben could be inhibited with the anti-oestrogen ICI 182 780. The proliferation of two oestrogen-dependent human breast cancer cell lines MCF7 and ZR-75-1 could be increased with isobutylparaben such that at concentrations of 10(-5) M the proliferation response was of the same magnitude as with 10(-8) M 17beta-oestradiol. Evidence for oestrogen receptor mediation of proliferation effects was provided by the inability of isobutylparaben to influence the growth of oestrogen-unresponsive MDA-MB-231 human breast cancer cells and by the ability of the anti-oestrogen ICI 182 780 to inhibit the isobutylparaben effects on MCF7 cell growth. The proliferation response to 10(-10) M 17beta-oestradiol was not antagonized with isobutylparaben at any concentration from 10(-9) M to 10(-4) M in either MCF7 or ZR-75-1 cells. Finally, subcutaneous administration of isobutylparaben was able to increase the uterine weight in the immature mouse after three daily doses of 1.2 or 12.0 mg per mouse. Previous work using linear-alkyl-chain parabens has shown that oestrogenic activity increases with alkyl chain length from methylparaben to n-butylparaben. The results here show that branching of the alkyl chain to isobutylparaben increases oestrogenic activity beyond that of the equivalent length linear alkyl chain in n-butylparaben.
Asunto(s)
Estradiol/análogos & derivados , Moduladores de los Receptores de Estrógeno , Estrógenos no Esteroides/toxicidad , Parabenos/toxicidad , Animales , Neoplasias de la Mama/metabolismo , División Celular , Relación Dosis-Respuesta a Droga , Estradiol/farmacología , Receptor alfa de Estrógeno , Estrógenos no Esteroides/antagonistas & inhibidores , Femenino , Fulvestrant , Regulación Neoplásica de la Expresión Génica , Humanos , Ligandos , Ratones , Ratones Endogámicos , Tamaño de los Órganos/efectos de los fármacos , Unión Proteica , Proteínas/genética , ARN Mensajero/genética , Receptores de Estrógenos/metabolismo , Factor Trefoil-1 , Células Tumorales Cultivadas , Proteínas Supresoras de Tumor , Útero/efectos de los fármacos , Útero/patologíaRESUMEN
Estradiol-17beta relaxes rabbit coronary artery rings via large conductance Ca2+-activated K+-channels (K(Ca)). Genistein and daidzein are plant-derived estrogen-like compounds. The aim of the present study was to investigate whether potassium channels participate in the genistein- and daidzein-induced arterial relaxation like they do in the case of estradiol-17beta. Endothelium-denuded superior mesenteric arterial rings from non-pregnant Wistar female rats were used. At a concentration of 10 microM, estradiol-17beta, genistein and daidzein relaxed noradrenaline precontracted arterial rings, (58 +/- 4%, 45 +/- 5% and 31 +/- 3%, respectively; (n=6-8)). Genistein- and daidzein-induced relaxations were inhibited both by iberiotoxin (1-10 nM) and charybdotoxin (30 nM), the antagonists of large conductance Ca2+-activated K+-channels (K(Ca)). Estradiol-17beta-induced relaxation was reduced by iberiotoxin (30 nM). Estradiol-17beta- and daidzein-induced relaxations were also decreased by apamin (0.1-0.3 microM), an antagonist of small conductance Ca2+-activated K+-channels. The antagonists of voltage-dependent K+-channels (K(V)) (4-aminopyridine), ATP-sensitive K+-channels (K(ATP)) (glibenclamide), or inward rectifier K+-channels (KIR) (barium) had no effect on the relaxation responses of any of the compounds studied. Estrogen receptor antagonist tamoxifen did not inhibit the relaxations. In conclusion, in the noradrenaline precontracted rat mesenteric arteries, the relaxations caused by estradiol-17beta, genistein and daidzein were antagonized by large and small conductance K(Ca)-channel inhibitors, suggesting the role of these channels as one of the relaxation mechanisms.
Asunto(s)
Caribdotoxina/farmacología , Estrógenos no Esteroides/antagonistas & inhibidores , Genisteína/antagonistas & inhibidores , Isoflavonas/antagonistas & inhibidores , Relajación Muscular/efectos de los fármacos , Péptidos/farmacología , Bloqueadores de los Canales de Potasio , Canales de Potasio Calcio-Activados , Animales , Apamina/farmacología , Interacciones Farmacológicas , Estradiol/farmacología , Estrógenos no Esteroides/farmacología , Femenino , Genisteína/farmacología , Técnicas In Vitro , Isoflavonas/farmacología , Canales de Potasio de Gran Conductancia Activados por el Calcio , Arterias Mesentéricas/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos , Canales de Potasio/metabolismo , Ratas , Ratas WistarRESUMEN
There is an increasing demand for natural compounds that improve women's health by mimicking the critical benefits of estrogen to the bones and the cardiovascular system but avoiding its deleterious effects on the breast and uterus. The estrogenic properties of glabridin, the major isoflavan in licorice root, were tested in view of the resemblance of its structure and lipophilicity to those of estradiol. The results indicate that glabridin is a phytoestrogen, binding to the human estrogen receptor and stimulating creatine kinase activity in rat uterus, epiphyseal cartilage, diaphyseal bone, aorta, and left ventricle of the heart. The stimulatory effects of 2.5-25 microg/animal glabridin were similar to those of 5 microg/animal estradiol. Chemical modification of glabridin showed that the position of the hydroxyl groups has a significant role in binding to the human estrogen receptor and in proliferation-inducing activity. Glabridin was found to be three to four times more active than 2'-O-methylglabridin and 4'-O-methylglabridin, and both derivatives were more active than 2',4'-O-methylglabridin. The effect of increasing concentrations of glabridin on the growth of breast tumor cells was biphasic. Glabridin showed an estrogen receptor-dependent, growth-promoting effect at low concentrations (10 nM-10 microM) and estrogen receptor-independent antiproliferative activity at concentrations of > 15 microM. This is the first study to indicate that isoflavans have estrogen-like activities. Glabridin and its derivatives exhibited varying degrees of estrogen receptor agonism in different tests and demonstrated growth-inhibitory actions on breast cancer cells.
Asunto(s)
Neoplasias de la Mama/patología , Estrógenos no Esteroides/farmacología , Fenoles/farmacología , Animales , Unión Competitiva , Neoplasias de la Mama/tratamiento farmacológico , Adhesión Celular/fisiología , División Celular/efectos de los fármacos , Creatina Quinasa/metabolismo , Interacciones Farmacológicas , Estradiol/metabolismo , Moduladores de los Receptores de Estrógeno/farmacología , Estrógenos no Esteroides/antagonistas & inhibidores , Estrógenos no Esteroides/metabolismo , Femenino , Humanos , Isoflavonas , Imitación Molecular , Especificidad de Órganos , Fenoles/antagonistas & inhibidores , Fenoles/metabolismo , Extractos Vegetales/antagonistas & inhibidores , Extractos Vegetales/metabolismo , Extractos Vegetales/farmacología , Ratas , Ratas Wistar , Receptores de Estrógenos/agonistas , Receptores de Estrógenos/metabolismo , Relación Estructura-Actividad , Tamoxifeno/farmacología , Células Tumorales Cultivadas/efectos de los fármacosRESUMEN
Previously, we reported that in vitro exposure of murine embryos to 0.1 microg/ml o,p'-DDT (an estrogenic pesticide) significantly reduced development to blastocyst and mean cell number per embryo, and increased percent cell death by 96 h of culture. The objective of the present study was to determine if developmental injury induced by o,p'-DDT resulted from estrogenic, antiestrogenic, or unrelated adverse biologic mechanisms. Toward this objective, pronuclear embryos from CD-1 mice were cultured 96 h in medium supplemented with 0.1% ethanol (control) or 0.1 microg/ml o,p'-DDT, 17beta-estradiol, or ICI 182,780 dissolved in ethanol as single agents or as paired mixtures. As single agents, development to blastocyst and mean cell numbers were significantly reduced and percent apoptosis was significantly increased for embryos cultured in the presence of o,p'-DDT or ICI 182,780. Development to blastocyst was significantly reduced for embryos cultured in the presence of 17beta-estradiol. Beneficial interaction occurred when the receptor antagonist ICI 182,780 was combined with either receptor agonist (o,p'-DDT or 17beta-estradiol). In contrast, interaction was not significant when the two agonists were combined. The results indicate that developmental injury due to the estrogenic pesticide o,p'-DDT was abolished by the addition of the receptor antagonist ICI 182,780 and not by the receptor agonist 17beta-estradiol. The findings underscore the utility of the model for uncovering mechanisms of developmental injury.
Asunto(s)
Blastocisto/efectos de los fármacos , DDT/toxicidad , Desarrollo Embrionario y Fetal/efectos de los fármacos , Estradiol/análogos & derivados , Antagonistas de Estrógenos/farmacología , Estrógenos no Esteroides/toxicidad , Animales , Apoptosis/efectos de los fármacos , Blastocisto/citología , Recuento de Células/efectos de los fármacos , DDT/antagonistas & inhibidores , Interacciones Farmacológicas , Desarrollo Embrionario , Estradiol/farmacología , Estrógenos no Esteroides/antagonistas & inhibidores , Femenino , Fulvestrant , Técnicas In Vitro , Masculino , Ratones , Modelos Biológicos , EmbarazoRESUMEN
4-tert-octyphenol (OP) is a surfactant additive widely used in the manufacture of a variety of detergents and plastic products. OP has been reported to mimic the actions of estrogen in many cellular systems. The present studies evaluated the direct effects of OP on human chorionic gonadotropin (hCG)-stimulated testosterone biosynthesis by cultured precursor and immature Leydig cells from 23-day old (prepubertal) rats. Exposure to increasing OP concentrations (1 to 2000 nM) progressively decreased hCG-stimulated testosterone formation in both precursor and immature Leydig cells at higher OP concentrations (100 or 500 to 2000 nM). Testosterone levels were reduced approximately 30 to 70% below control at the highest concentration in both cell types. Similar reductions in testosterone associated with OP exposure were observed in cells stimulated with 1 mM 8-Br-cAMP, suggesting that the main actions of OP occur after the generation of cAMP. Increasing concentrations of 17beta-estradiol (1 to 1000 nM) had no effect on hCG-stimulated testosterone formation in both precursor and immature Leydig cells and the inclusion of 100 nM ICI 182,780, a pure estrogen antagonist, in precursor and immature Leydig cells exposed to OP and hCG, did not alter the inhibition by higher OP concentrations of testosterone formation in both cell types. These results suggest that OP is a hormonally active agent, but that some of its actions are distinct from those of 17beta-estradiol and are not mediated through the estrogen receptor alpha or beta pathway. To further localize the potential site(s) of action of OP, cultured precursor and immature Leydig cells were exposed to increasing concentrations of OP and hCG for 24 h. Next, fresh media containing 1 microM 22(R)-hydroxycholesterol, 1 microM pregnenolone, 1 microM progesterone, or 1 microM androstenedione was added, and the conversion of each substrate to testosterone was determined after incubation for 4 h. The conversion of androstenedione to testosterone was unaffected by exposure to OP, suggesting that the 17beta-hydroxysteroid dehydrogenase step is not inhibited. However, the conversion of 22(R)-hydroxycholesterol, pregnenolone and progesterone all were inhibited by prior exposure to OP and hCG. This finding suggests that the 17alpha-hydroxylase/c17-20-lyase step, which converts progesterone to androstenedione, is inhibited by OP, and that the cholesterol side-chain cleavage and 3beta-hydroxysteroid dehydrogenase -isomerase steps, which convert cholesterol to pregnenolone and pregnenolone to progesterone, respectively, are other potential sites of OP action. Because concomitant exposure to the antioxidants alpha-tocopherol or ascorbate did not alter the inhibition of testosterone formation by higher OP concentrations, it does not appear that OP is acting as a pseudosubstrate for the generation of free radicals, which can damage P450 enzymes.
Asunto(s)
Estrógenos no Esteroides/toxicidad , Células Intersticiales del Testículo/efectos de los fármacos , Fenoles/toxicidad , Testosterona/biosíntesis , Androstenodiona/metabolismo , Androstenodiona/farmacología , Animales , Células Cultivadas , Gonadotropina Coriónica/farmacología , AMP Cíclico/análogos & derivados , AMP Cíclico/farmacología , Relación Dosis-Respuesta a Droga , Estradiol/análogos & derivados , Estradiol/farmacología , Antagonistas de Estrógenos/farmacología , Estrógenos no Esteroides/antagonistas & inhibidores , Fulvestrant , Hidroxicolesteroles/metabolismo , Hidroxicolesteroles/farmacología , Células Intersticiales del Testículo/metabolismo , Masculino , Pregnenolona/metabolismo , Pregnenolona/farmacología , Progesterona/metabolismo , Progesterona/farmacología , Ratas , Ratas Sprague-Dawley , Testosterona/antagonistas & inhibidoresRESUMEN
The interaction between the recombinant human estrogen receptor and a variety of nonsteroidal estrogens was studied using a transient transfection assay in mammalian cells. Eight naturally occurring compounds were confirmed to stimulate the transcriptional activity of the human estrogen receptor and to compete for the binding of radiolabeled 17 beta-estradiol to this protein. In order of biological potency, these were zearalenone, beta-zearalenol, coumestrol, genistein, daidzein, phloretin, formononetin, and biochanin A. As with steroidal estrogens, the hormonal activity of these compounds was specific for the estrogen receptor and sensitive to inhibition by 4-hydroxytamoxifen and ICI-164,384. Evidence is also presented to indicate that the stimulatory activity of genistein is unrelated to the protein tyrosine kinase inhibitory activity of this isoflavone. These results demonstrate that a significant number of structurally diverse plant and fungal secondary metabolites exist in nature that may contribute to the total estrogen exposure of the human population.