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See detailEstradiol stimulation of Pulsatile gonadotropin-releasing hormone secretion in vitro: Correlation with perinatal exposure to sex steroids and induction of sexual precocity in vivo
Matagne, V.; Rasier, G.; LEBRETHON, Marie-Christine ULg et al

in Endocrinology (2004), 145(6), 2775-2783

Our aim was to study the effect of estradiol (E2) on pulsatile GnRH secretion in vitro in relation to sex and development. When hypothalamic explants obtained from 5- and 15-d-old female rats were exposed ... [more ▼]

Our aim was to study the effect of estradiol (E2) on pulsatile GnRH secretion in vitro in relation to sex and development. When hypothalamic explants obtained from 5- and 15-d-old female rats were exposed to E2 (10(-7) m), a reduction of GnRH interpulse interval (IPI) occurred but not at 25 and 50 d of age. This effect was prevented by the estrogen receptor antagonist ICI 182.780 and the AMPA/kainate receptor antagonist DNQX but not by the AMPA and N-methyl-D-aspartate receptor antagonists SYM 2206 and MK-801. E2 did not affect GnRH IPI in hypothalamic explants obtained from male rats. Therefore, the possible relation between the female-specific effects of E2 in vitro and perinatal sexual differentiation was investigated. When using explants obtained from female rats masculinized through testosterone injection on postnatal d 1, E2 was no longer effective in vitro at 5 and 15 d. In addition, with explants obtained from male rats demasculinized through perinatal aromatase inhibitor treatment, E2 became capable of decreasing GnRH IPI in vitro at 15 d. To study the possible pathophysiological significance of early hypothalamic E2 effects, female rats received a single E2 injection on postnatal d 10. This resulted in reduced GnRH IPI in vitro on d 15 as well as advancement in age at vaginal opening and first estrus. In conclusion, E2 decreases the GnRH IPI in the immature female hypothalamus in vitro through a mechanism that depends on perinatal brain sexual differentiation and that could be involved in some forms of female precocious puberty. [less ▲]

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See detailEstradiol, a key endocrine signal in the sexual differentiation and activation of reproductive behavior in quail
Balthazart, Jacques ULg

in Comparative Biochemistry & Physiology Part A : Molecular & Integrative Physiology (2007, August), 148(Suppl. 1), 27

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See detailEstradiol, a key endocrine signal in the sexual differentiation and activation of reproductive behavior in quail.
Balthazart, Jacques ULg; Cornil, Charlotte ULg; Charlier, Thierry ULg et al

in Journal of Experimental Zoology. Part A, Ecological Genetics and Physiology (2009), 311(5), 323-45

In Japanese quail, estrogen's effects on sexual behavior can be divided into three classes based on the underlying mechanisms and time-course of action and release. During embryonic life, the embryonic ... [more ▼]

In Japanese quail, estrogen's effects on sexual behavior can be divided into three classes based on the underlying mechanisms and time-course of action and release. During embryonic life, the embryonic ovary secretes large amounts of estrogens. In contrast to what is observed in mammals where sexual differentiation essentially proceeds via masculinization of the males, in quail, females are demasculinized by their endogenous ovarian estrogens, an effect that can be blocked by injection of an aromatase inhibitor and mimicked in male embryos by an injection of estradiol. In adulthood, testosterone secreted by the testes is converted into estrogens by the preoptic aromatase. Locally produced estrogens activate male sexual behavior largely through the activation of estrogen receptors resulting in the transcription of a variety of genes, including brain aromatase (genomic effect). Both changes in estrogen production and action are observed within latencies ranging from a few hours to a few days, and are completely reversible. Additionally, brain aromatase activity can be modulated within minutes by calcium-dependent phosphorylations, triggered by variations in glutamatergic neurotransmission. These rapid changes in aromatase activity affect with relatively short latencies (10-15 min) the expression of male sexual behavior in quail and also in mice. Overall, the effects of estrogens on sexual behavior can thus be categorized into three classes: organizational (irreversible genomic action during ontogeny), activational (reversible genomic action during adulthood) and rapid nongenomic effects. Rapid and slower changes in brain aromatase activity match well with the two modes of estrogen action on behavior and provide temporal variations in the estrogens' bioavailability that should be able to support the entire range of established effects for this steroid. [less ▲]

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See detailEstradiol-induced neurogenesis in the female accessory olfactory bulb is required for the learning of the male odor.
Brus, Maina; Trouillet, Anne-Charlotte; Hellier, Vincent ULg et al

in Journal of Neurochemistry (2016)

Odors processed by the main and accessory olfactory bulbs (MOB, AOB) are important for sexual behavior. Interestingly, both structures continue to receive new neurons during adulthood. A role for ... [more ▼]

Odors processed by the main and accessory olfactory bulbs (MOB, AOB) are important for sexual behavior. Interestingly, both structures continue to receive new neurons during adulthood. A role for olfactory neurogenesis in sexual behavior in female mice has recently been shown and gonadal hormones such as estradiol can modulate adult neurogenesis. Therefore, we wanted to determine the role of estradiol in learning the odors of sexual partners and in the adult neurogenesis of female aromatase-knockout mice (ArKO), unable to produce estradiol. Female WT and ArKO mice were exposed to male odors during 7 days and olfactory preferences, cell proliferation, cell survival and functional involvement of newborn neurons were analyzed, using BrdU injections, in combination with a marker of cell activation (Zif268) and neuronal fate (DCX, NeuN). Behavioral tasks indicated that both WT and ArKO females were able to discriminate between the odors of two different males, but ArKO mice failed to learn the familiar male odor. Proliferation of newborn cells was reduced in ArKO mice only in the dentate gyrus of the hippocampus. Olfactory exposure decreased cell survival in the AOB in WT females, suggesting a role for estradiol in a structure involved in sexual behavior. Finally, newborn neurons do not seem to be functionally involved in the AOB of ArKO mice compared with WT, when females were exposed to the odor of a familiar male, suggesting that estradiol-induced neurogenesis in the AOB is required for the learning of the male odor in female mice. This article is protected by copyright. All rights reserved. [less ▲]

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See detailEstrategias de una traducción literal
Willson, Patricia ULg

Article for general public (2015)

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See detailEstrategias sociopreventivas del hooliganismo
Comeron, Manuel ULg

in Colome, Gabriel (Ed.) Politica y Deporte (2001)

Une analyse comparative en Europe (Angleterre, Belgique, France, Espagne): évolution des politiques sportives, le sport et l'Etat, la lutte contre le hooliganisme, les stratégies préventives, le sport ... [more ▼]

Une analyse comparative en Europe (Angleterre, Belgique, France, Espagne): évolution des politiques sportives, le sport et l'Etat, la lutte contre le hooliganisme, les stratégies préventives, le sport comme spectacle médiatique. [less ▲]

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See detailEstrogen activation revisited: control of local metabolism in the brain
Charlier, Thierry ULg

Scientific conference (2012)

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See detailEstrogen and pain: a study in aromatase knock-out mice using the formalin model.
Multon, Sylvie ULg

Conference (2004, September)

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See detailEstrogen Receptor β Activation Rapidly Modulates Male Sexual Motivation through the Transactivation of Metabotropic Glutamate Receptor 1a
Seredynski, Aurore L; Balthazart, Jacques ULg; Ball, Gregory F et al

in Journal of Neuroscience (2015), 35(38), 13110-23

In addition to the transcriptional activity of their liganded nuclear receptors, estrogens, such as estradiol (E2), modulate cell functions, and consequently physiology and behavior, within minutes ... [more ▼]

In addition to the transcriptional activity of their liganded nuclear receptors, estrogens, such as estradiol (E2), modulate cell functions, and consequently physiology and behavior, within minutes through membrane-initiated events. The membrane-associated receptors (mERs) underlying the acute effects of estrogens on behavior have mostly been documented in females where active estrogens are thought to be of ovarian origin. We determined here, by acute intracerebroventricular injections of specific agonists and antagonists, the type(s) of mERs that modulate rapid effects of brain-derived estrogens on sexual motivation in male Japanese quail. Brain aromatase blockade acutely inhibited sexual motivation. Diarylpropionitrile (DPN), an estrogen receptor β (ERβ)-specific agonist, and to a lesser extent 17α-estradiol, possibly acting through ER-X, prevented this effect. In contrast, drugs targeting ERα (PPT and MPP), GPR30 (G1 and G15), and the Gq-mER (STX) did not affect sexual motivation. The mGluR1a antagonist LY367385 significantly inhibited sexual motivation but mGluR2/3 and mGluR5 antagonists were ineffective. LY367385 also blocked the behavioral restoration induced by E2 or DPN, providing functional evidence that ERβ interacts with metabotropic glutamate receptor 1a (mGluR1a) signaling to acutely regulate male sexual motivation. Together these results show that ERβ plays a key role in sexual behavior regulation and the recently uncovered cooperation between mERs and mGluRs is functional in males where it mediates the acute effects of estrogens produced centrally in response to social stimuli. The presence of an ER-mGluR interaction in birds suggests that this mechanism emerged relatively early in vertebrate history and is well conserved. Significance statement: The membrane-associated receptors underlying the acute effects of estrogens on behavior have mostly been documented in females, where active estrogens are thought to be of ovarian origin. Using acute intracerebroventricular injections of specific agonists and antagonists following blockade of brain aromatase, we show here that brain-derived estrogens acutely facilitate male sexual motivation through the activation of estrogen receptor β interacting with the metabotropic glutamate receptor 1a. This behavioral effect occurring within minutes provides a mechanistic explanation of how an estrogen receptor not intrinsically coupled to intracellular effectors can signal from the membrane to govern behavior in a very rapid fashion. It suggests that different subtypes of estrogen receptors could regulate the motivation versus performance aspects of behavior. [less ▲]

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See detailEstrogen Receptor-Beta in Quail: Cloning, Tissue Expression and Neuroanatomical Distribution
Foidart, Agnès ULg; Lakaye, Bernard ULg; Grisar, Thierry ULg et al

in Journal of Neurobiology (1999), 40(3), 327-42

A partial estrogen receptor-beta (ERbeta) cDNA had been previously cloned and sequenced in Japanese quail. The 3'- and 5'-rapid amplification of cDNA ends techniques were used here to identify a cDNA ... [more ▼]

A partial estrogen receptor-beta (ERbeta) cDNA had been previously cloned and sequenced in Japanese quail. The 3'- and 5'-rapid amplification of cDNA ends techniques were used here to identify a cDNA sequence of the quail ERbeta that contains a complete open reading frame. For the first time in an avian species, this cDNA sequence and the corresponding amino acid sequence are described. They are compared with the known ERbeta sequences previously described in mammals and with the ERalpha sequences identified in a selection of mammalian and avian species. The analysis by Northern blotting of the ERbeta mRNA expression in the brain and kidneys revealed the presence of several transcripts. The presence of ERbeta identified by reverse transcriptase-polymerase chain reaction demonstrated a widespread distribution quite different from the distribution of ERalpha. The complete neuroanatomical distribution of ERbeta mRNA as determined by in situ hybridization with 35S- and 33P-labeled oligoprobes is also presented. Transcripts are present in many nuclei implicated in the control of reproduction such as the medial preoptic nucleus, the nucleus striae terminalis, and the nucleus taeniae, the avian homologue of the amygdala. These data demonstrate the presence of ERbeta in a nonmammalian species and indicate that the (neuro)-anatomical distribution of this receptor type has been conserved in these two classes of vertebrates. The role of this receptor in the control of reproduction and other physiological processes should now be investigated. [less ▲]

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See detailEstrogen replacement therapy and inhibition of bone resorption
Reginster, Jean-Yves ULg; Sarlet, N; Albert, Adelin ULg et al

in Revue du Rhumatisme et des Maladies Osteo-Articulaires (1992), 59

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See detailEstrogen-deficient female but not male aromatase knockout (ArKO) mice exhibit "depressive-like" symptoms
Bakker, Julie ULg; Dalla, C.; Antoniou, K. et al

in Hormones & Behavior (2004, June), 46(1), 127

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See detailEstrogenic components for use in the treatment of neurological disorders
Foidart, Jean-Michel ULg; Tskitishvili, Ekaterine ULg

Patent (2013)

The invention relates to the prophylactic and therapeutic applications of certain estrogenic components such as estetrol in neurological disorders such as neonatal hypoxic-ischemic encephalopathy (HIE).

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See detailEstrogenic Evaluation and Organochlorine Identification in Blubber of North Sea Harbour Porpoise (Phocoena phocoena) Stranded on the North Sea Coast
Didimo Imazaki, Pedro Henrique ULg; Brose, François ULg; Jauniaux, Thierry ULg et al

in BioMed Research International (2015), Volume 2015(Article ID 438295), 13

Thirteen individual organochlorine compounds at 3 concentrations (80, 400, and 2000 ng/mL culture medium), as well as mixtures, were assayed for the estrogen receptor (ER) activation or inhibition, using ... [more ▼]

Thirteen individual organochlorine compounds at 3 concentrations (80, 400, and 2000 ng/mL culture medium), as well as mixtures, were assayed for the estrogen receptor (ER) activation or inhibition, using a luciferase reporter gene assay (RGA). None of the PCB 138, 153, or 180 or their mixture induced a response in the RGA. o,p'-DDT was the most potent xenoestrogen fromthe DDT group, inducing a response already at 80 ng/mL. From the HCH and HCB group, only 𝛽-HCH (at 400 and 2000 ng/mL) and 𝛿-HCH (at 2000 ng/mL) displayed estrogenic activities.These 13 organochlorines were determined by GC-MS in 12 samples of North Sea harbor porpoise blubber. The PCBs were the main contaminants. Within each group, PCB 153 (6.0 × 102∼4.2 × 104 𝜇g/kg), p,p'- DDE (5.1 × 102∼8.6 × 103 𝜇g/kg), and HCB (7.6 × 101∼1.5 × 103 𝜇g/kg) were the compounds found in highest concentrations.The hormonal activity of the porpoise blubber samples was also assayed in RGA, where two samples showed estrogenic activity, seven samples showed antiestrogenic activity, and one sample showed both estrogenic and antiestrogenic activity. Our results suggest that the 13 POPs measured by GC-MS in the samples cannot explain alone the estrogenicity of the extracts. [less ▲]

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See detailEstrogens and neonatal neuroprotection
Pequeux, Christel ULg; Tskitishvili, Ekaterine ULg

Scientific conference (2014, November 27)

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