Xenoestrogen-Induced ERK-1 and ERK-2 Activation via Multiple Membrane-Initiated Signaling Pathways

Xenoestrogens can mimic or antagonize the activity of physiological estrogens, and the suggested mechanism of xenoestrogen action involves binding to estrogen receptors (ERs). However, the failure of various in vitro or in vivo assays to show strong genomic activity of xenoestrogens compared with estradiol (E(2)) makes it difficult to explain their ability to cause abnormalities in animal (and perhaps human) reproductive functions via this pathway of steroid action. E(2) has also been shown to initiate rapid intracellular signaling, such as changes in levels of intracellular calcium, cAMP, and nitric oxide, and activations of a variety of kinases, via action at the membrane. In this study, we demonstrate that several xenoestrogens can rapidly activate extracellular-regulated kinases (ERKs) in the pituitary tumor cell line GH(3)/B6/F10, which expresses high levels of the membrane receptor for ER-α(mER). We tested a phytoestrogen (coumestrol), organochlorine pesticides or their metabolites (endosulfan, dieldrin, and DDE), and detergent by-products of plastics manufacturing (p-nonylphenol and bisphenol A). These xenoestrogens (except bisphenol A) produced rapid (3–30 min after application), concentration (10(−14)–10(−8) M)-dependent ERK-1/2 phosphorylation but with distinctly different activation patterns. To identify signaling pathways involved in ERK activation, we used specific inhibitors of ERs, epidermal growth factor receptors, Ca(2+) signaling, Src and phosphoinositide-3 kinases, and a membrane structure disruption agent. Multiple inhibitors blocked ERK activation, suggesting simultaneous use of multiple pathways and complex signaling web interactions. However, inhibitors differentially affected each xenoestrogen response examined. These actions may help to explain the distinct abilities of xenoestrogens to disrupt reproductive functions at low concentrations

Nasjonalreligiøsitet i Norge mellom 1850 og 1950 - En analyse av Oalvskulten og Kristen Samling som ulike uttrykk for nasjonalreligiøsitet

Denne oppgaven skal undersøke de ulike formene for nasjonalreligiøsitet som kommer til uttrykk gjennom fremveksten av Olavskulten mot slutten av 1890-årene og utover mot 1950-tallet, sammen med utviklingen av organisasjonen Kristen Samling som i hovedsak besto av kristne NS-medlemmer under krigen. Gjennom oppgaven vil ulike deler av nasjonsbegrepet, nasjon, nasjonalreligiøsitet og nasjonalisme, bli gjennomgått med henblikk på forståelsen av religion og religiøsitet. En sentral del av oppgaven er å se på hvordan formidlingen av historiske begivenheter har vært med på å forme det kollektive minnet slik at det bidrar til å fremme politiske og nasjonal enhet

Xenoestrogen-Induced ERK-1 and ERK-2 Activation via Multiple Membrane-Initiated Signaling Pathways-3

<p><b>Copyright information:</b></p><p>Taken from "Xenoestrogen-Induced ERK-1 and ERK-2 Activation via Multiple Membrane-Initiated Signaling Pathways"</p><p>Environmental Health Perspectives 2004;112(15):1481-1487.</p><p>Published online 28 Jul 2004</p><p>PMCID:PMC1325963.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI.</p

Xenoestrogen-Induced ERK-1 and ERK-2 Activation via Multiple Membrane-Initiated Signaling Pathways-2

<p><b>Copyright information:</b></p><p>Taken from "Xenoestrogen-Induced ERK-1 and ERK-2 Activation via Multiple Membrane-Initiated Signaling Pathways"</p><p>Environmental Health Perspectives 2004;112(15):1481-1487.</p><p>Published online 28 Jul 2004</p><p>PMCID:PMC1325963.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI.</p

Xenoestrogens at Picomolar to Nanomolar Concentrations Trigger Membrane Estrogen Receptor-α–Mediated Ca Fluxes and Prolactin Release in GH3/B6 Pituitary Tumor Cells-2

<p><b>Copyright information:</b></p><p>Taken from "Xenoestrogens at Picomolar to Nanomolar Concentrations Trigger Membrane Estrogen Receptor-α–Mediated Ca Fluxes and Prolactin Release in GH3/B6 Pituitary Tumor Cells"</p><p>Environmental Health Perspectives 2005;113(4):431-439.</p><p>Published online 14 Jan 2005</p><p>PMCID:PMC1278483.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI.</p

Xenoestrogens at Picomolar to Nanomolar Concentrations Trigger Membrane Estrogen Receptor-α–Mediated Ca Fluxes and Prolactin Release in GH3/B6 Pituitary Tumor Cells-6

<p><b>Copyright information:</b></p><p>Taken from "Xenoestrogens at Picomolar to Nanomolar Concentrations Trigger Membrane Estrogen Receptor-α–Mediated Ca Fluxes and Prolactin Release in GH3/B6 Pituitary Tumor Cells"</p><p>Environmental Health Perspectives 2005;113(4):431-439.</p><p>Published online 14 Jan 2005</p><p>PMCID:PMC1278483.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI.</p

Xenoestrogens at Picomolar to Nanomolar Concentrations Trigger Membrane Estrogen Receptor-α–Mediated Ca Fluxes and Prolactin Release in GH3/B6 Pituitary Tumor Cells-8

<p><b>Copyright information:</b></p><p>Taken from "Xenoestrogens at Picomolar to Nanomolar Concentrations Trigger Membrane Estrogen Receptor-α–Mediated Ca Fluxes and Prolactin Release in GH3/B6 Pituitary Tumor Cells"</p><p>Environmental Health Perspectives 2005;113(4):431-439.</p><p>Published online 14 Jan 2005</p><p>PMCID:PMC1278483.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI.</p