Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Sci Rep ; 14(1): 6402, 2024 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-38493224

RESUMO

Allopregnanolone (ALLO) is a known neurosteroid and a progesterone metabolite synthesized in the ovary, CNS, PNS, adrenals and placenta. Its role in the neuroendocrine control of ovarian physiology has been studied, but its in situ ovarian effects are still largely unknown. The aims of this work were to characterize the effects of intrabursal ALLO administration on different ovarian parameters, and the probable mechanism of action. ALLO administration increased serum progesterone concentration and ovarian 3ß-HSD2 while decreasing 20α-HSD mRNA expression. ALLO increased the number of atretic follicles and the number of positive TUNEL granulosa and theca cells, while decreasing positive PCNA immunostaining. On the other hand, there was an increase in corpora lutea diameter and PCNA immunostaining, whereas the count of TUNEL-positive luteal cells decreased. Ovarian angiogenesis and the immunohistochemical expression of GABAA receptor increased after ALLO treatment. To evaluate if the ovarian GABAA receptor was involved in these effects, we conducted a functional experiment with a specific antagonist, bicuculline. The administration of bicuculline restored the number of atretic follicles and the diameter of corpora lutea to normal values. These results show the actions of ALLO on the ovarian physiology of the female rat during the follicular phase, some of them through the GABAA receptor. Intrabursal ALLO administration alters several processes of the ovarian morpho-physiology of the female rat, related to fertility and oocyte quality.


Assuntos
Pregnanolona , Progesterona , Gravidez , Feminino , Ratos , Animais , Pregnanolona/farmacologia , Progesterona/farmacologia , Antígeno Nuclear de Célula em Proliferação , Bicuculina/farmacologia , Receptores de GABA-A , Corpo Lúteo
2.
J Endocrinol ; 258(1)2023 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-37115241

RESUMO

Neuroactive steroids can rapidly regulate multiple physiological functions in the central and peripheral nervous systems. The aims of the present study were to determine whether allopregnanolone (ALLO), administered in low nanomolar and high micromolar concentrations, can: (i) induce changes in the ovarian progesterone (P4) and estradiol (E2) release; (ii) modify the ovarian mRNA expression of Hsd3b1 (3ß-hydroxysteroid dehydrogenase, 3ß-HSD)3ß-, Akr1c3 (20α-hydroxysteroid dehydrogenase, 20α-HSD), and Akr1c14 (3α-hydroxy steroid oxidoreductase, 3α-HSOR)); and (iii) modulate the ovarian expression of progesterone receptors A and B, α and ß estrogenic receptors, luteinizing hormone receptor (LHR) and follicle-stimulating hormone receptor (FSHR). To further characterize ALLO peripheral actions, the effects were evaluated using a superior mesenteric ganglion-ovarian nervous plexus-ovary (SMG-ONP-O) and a denervated ovary (DO) systems. ALLO SMG administration increased P4 concentration in the incubation liquid by decreasing ovarian 20α-HSD mRNA, and it also increased ovarian 3α-HSOR mRNA expression. In addition, ALLO neural peripheral modulation induced an increase in the expression of ovarian LHR, PRA, PRB, and ERα. Direct ALLO administration to the DO decreased E2 and increased P4 concentration in the incubation liquid. The mRNA expression of 3ß-HSD decreased and 20α-HSD increased. Further, ALLO in the OD significantly changed ovarian FSHR and PRA expression. This is the first evidence of ALLO's direct effect on ovarian steroidogenesis. Our results provide important insights about how this neuroactive steroid interacts both with the PNS and the ovary, and these findings might help devise some of the pleiotropic effects of neuroactive steroids on female reproduction. Moreover, ALLO modulation of ovarian physiology might help uncover novel treatment approaches for reproductive diseases.


Assuntos
Neuroesteroides , Pregnanolona , Feminino , Humanos , Pregnanolona/farmacologia , Pregnanolona/metabolismo , Neuroesteroides/metabolismo , Neuroesteroides/farmacologia , Ovário/metabolismo , Progesterona/farmacologia , Progesterona/metabolismo , Hidroxiesteroide Desidrogenases/metabolismo , Hidroxiesteroide Desidrogenases/farmacologia , RNA Mensageiro/metabolismo , 3-Hidroxiesteroide Desidrogenases/genética , 3-Hidroxiesteroide Desidrogenases/metabolismo , 3-Hidroxiesteroide Desidrogenases/farmacologia
3.
Rev. argent. salud publica ; 14: 1-6, 20 de Enero del 2022.
Artigo em Espanhol | LILACS, ARGMSAL, BINACIS | ID: biblio-1353391

RESUMO

INTRODUCCIÓN: A través de la Red Ministerial de Investigación en Salud (REMINSA) se actualizó el estado de situación de las áreas provinciales de investigación en salud pública. MÉTODOS: Se realizaron reuniones virtuales de debate con los referentes REMINSA y una encuesta en Google Forms® sobre funcionamiento normativo, organizacional, presupuestario, alcance de tareas y necesidades de mejoras. RESULTADOS: Se recibieron 21 respuestas de un total de 21 provincias con referentes. Se verificó la existencia de un amplio marco de normativas regulatorias de la investigación en salud humana y, en menor medida, para impulsar la investigación en el marco de la salud pública. El 71% tiene cierta estructura institucional, el 20% ofrece becas de investigación, y el 20% posee residencias con perfil en investigación. La principal actividad es la regulación o participación en comités de ética. La promoción, difusión de resultados y elaboración de proyectos de investigación basada en evidencia quedaron relegadas (20%). Las áreas de investigación están consolidadas en la mayoría de las provincias. DISCUSIÓN: El desafío consiste en promover el desarrollo de estos sistemas en las provincias que no cuentan con áreas ministeriales y fortalecer las provincias que sí las poseen. REMINSA ha identificado oportunidades de mejorar la comunicación entre jurisdicciones, las normativas de promoción de la investigación y el trabajo en red para la investigación, la gestión y la toma de decisiones.


Assuntos
Saúde Pública , Política de Pesquisa em Saúde , Promoção da Pesquisa , Argentina
4.
J Neuroendocrinol ; 34(2): e13056, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34739183

RESUMO

Allopregnanolone (ALLO), a potent neuroactive steroid, is synthesized and active in the peripheral nervous system. Previous studies have shown that ALLO participates in the central regulation of reproduction with effects on ovarian physiology, although there is little evidence for its ability to modulate peripheral tissues. The present study aimed to determine whether ALLO, administered to an ex vivo system that comprises the superior mesenteric ganglion (SMG), the ovarian nervous plexus (ONP) and the ovary (O), or to the denervated ovary (DO), was able to modify ovarian apoptosis, proliferation and angiogenesis. For this purpose, the SMG-ONP-O system and DO were incubated during 120 min at 37°C, in the presence of two ALLO doses (0.06 µm and 6 µm). The intrinsic and extrinsic pathways of apoptosis were analyzed. Incubation of the SMG-ONP-O system with ALLO 0.06 µm led to an increase in the BAX/BCL-2 ratio and a reduction of FAS-L mRNA levels. ALLO 6 µm induced a decrease of FAS-L levels. Incubation of DO with ALLO 0.06 µm reduced FAS-L, whereas ALLO 6 µm significantly increased it. Cyclin D1 mRNA was measured to evaluate proliferation. Treatment with ALLO 6 µm increased proliferation in both SMG-ONP-O and DO. ALLO 0.06 µm produced an increase of Cyclin D1 in DO only. Administration of either ALLO dose led to a higher ovarian expression of vascular endothelial growth factor in the SMG-ONP-O system, but a lower one in the DO system. ALLO 6 µm induced ovarian sensitization to GABA by increasing GABAA receptor expression. In conclusion, ALLO participates in the peripheral neural modulation of ovarian physiology. It can also interact directly with the ovarian tissue, modulating key mechanisms involved in normal and pathological processes in a dose-dependent manner.


Assuntos
Neuroesteroides , Pregnanolona , Apoptose , Proliferação de Células , Ciclina D1/metabolismo , Ciclina D1/farmacologia , Feminino , Humanos , Ovário/metabolismo , Pregnanolona/metabolismo , Pregnanolona/farmacologia , RNA Mensageiro/metabolismo , Receptores de GABA-A/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Fator A de Crescimento do Endotélio Vascular/farmacologia
5.
Ciudad Autónoma de Buenos Aires; Ministerio de Salud de la Nación; 13 Diciembre 2021. 43 p.
Monografia em Espanhol | ARGMSAL, BINACIS | ID: biblio-1348900

RESUMO

INTRODUCCIÓN: Una Agenda Nacional de Investigación en Salud Pública (ANISP) participativa y con priorización temática constituye un elemento estratégico para generar recomendaciones y políticas públicas basadas en evidencia, que impacten positivamente en la salud de las poblaciones y permitan lograr los objetivos sanitarios. En la actualización de la ANISP participaron la Dirección de Investigación en Salud (DIS) del Ministerio de Salud de la Nación (MSAL), a través de la Red Ministerial de Investigación en Salud (REMINSA), y actores de los niveles gubernamentales provinciales y nacionales pertenecientes a los sectores público, privado, de la salud, académico y de investigación. Se adaptó la herramienta original propuesta por la Organización Panamericana de la Salud, utilizada en el proceso en 2019. La actualización abarcó diferentes etapas. La selección de los temas contó con la legitimidad, reconocimiento y participación de los actores vinculados a la salud, a la gestión gubernamental y privada y a la investigación científica; se trabajó de manera federal y transversal, por consenso con las redes provinciales y un Comité Central Asesor en el MSAL. A partir de los lineamientos preliminares obtenidos, se elaboró una encuesta en línea semiestructurada, que fue distribuida a todos los actores federales y recibió 431 respuestas. El proceso resultó en 55 lineamientos priorizados, divididos en 6 áreas temáticas y 33 subtemas, seleccionados por votación según importancia, impacto y factibilidad.


Assuntos
Argentina , Pesquisa , Saúde Pública
6.
Rev. argent. salud publica ; 13: 301-310, 5/02/2021. graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1340934

RESUMO

RESUMEN INTRODUCCIÓN : Una Agenda Nacional de Investigación en Salud Pública (ANISP) participativa y con priorización temática constituye un elemento estratégico para generar recomendaciones y políticas públicas basadas en evidencia, que imparten positivamente en la salud de las poblaciones y permitan lograr los objetivos sanitarios. En la actualización de la ANISP participaron la Dirección de Investigación en Salud (DIS) del Ministerio de Salud de la Nación (MSAL), a través de la Red Ministerial de Investigación en Salud (REMINSA), y actores de los niveles gubernamentales provinciales y nacionales pertenecientes a los sectores público, privado, de la salud, académico y de investigación. Se adaptó la herramienta original propuesta por la Organización Panamericana de la Salud, utilizada en el proceso en 2019. La actualización abarcó diferentes etapas. La selección de los temas contó con la legitimidad, reconocimiento y participación de los actores vinculados a la salud, a la gestión gubernamental y privada y a la investigación científica; se trabajó de manera federal y transversal, por consenso con las redes provinciales y un Comité Central Asesor en el MSAL. A partir de los lineamientos preliminares obtenidos, se elaboró una encuesta en línea semiestructurada, que fue distribuida a todos los actores federales y recibió 431 respuestas. El proceso resultó en 55 lineamientos priorizados, divididos en 6 áreas temáticas y 33 subtemas, seleccionados por votación según importancia, impacto y factibilidad.


ABSTRACT INTRODUCTION : A participatory National Public Health Research Agenda (ANISP) with thematic prioritization is a strategic element to generóte evidence-based recommendations and public policies that have a positive impact on the health of populations and enable to achieve health objectives. The Directorate of Health Research (DIS) ofthe Argentine Ministry of Health (MSAL), through the Ministerial NetWork of Health Research (REMINSA), along with adors from the provincial and national government levels belonging to public, privóte, health, academic and research sectors participated in the update of the ANISP. They adapted the original tooI proposed by the Pan American Health Organizatlon and used in the process in 2019. The update included different stages. The selection ofthe topics had the legitimacy, recognition and participation ofthe actors involved, related to health, to government and privóte management and to scientific research; the work was conducted in a federal and transversal manner by consensus with the provincial networks and a Central Advisory Committee in the MSAL. Based on the preliminary guidelines obtained, a semi-structured online survey was developed and distributed to all federal actors, receiving 431 responses. The process resulted in 55 priorilized guidelines, divided into 6 thematic oreas and 33 sub-themes, selected by voting according to importance, impact and feasibility.

7.
Rev. argent. salud publica ; 13: 1-6, 5/02/2021.
Artigo em Espanhol | LILACS, ARGMSAL, BINACIS | ID: biblio-1291875

RESUMO

INTRODUCCIÓN: Una Agenda Nacional de Investigación en Salud Pública (ANISP) participativa y con priorización temática constituye un elemento estratégico para generar recomendaciones y políticas públicas basadas en evidencia, que impacten positivamente en la salud de las poblaciones y permitan lograr los objetivos sanitarios. En la actualización de la ANISP participaron la Dirección de Investigación en Salud (DIS) del Ministerio de Salud de la Nación (MSAL), a través de la Red Ministerial de Investigación en Salud (REMINSA), y actores de los niveles gubernamentales provinciales y nacionales pertenecientes a los sectores público, privado, de la salud, académico y de investigación. Se adaptó la herramienta original propuesta por la Organización Panamericana de la Salud, utilizada en el proceso en 2019. La actualización abarcó diferentes etapas. La selección de los temas contó con la legitimidad, reconocimiento y participación de los actores vinculados a la salud, a la gestión gubernamental y privada y a la investigación científica; se trabajó de manera federal y transversal, por consenso con las redes provinciales y un Comité Central Asesor en el MSAL. A partir de los lineamientos preliminares obtenidos, se elaboró una encuesta en línea semiestructurada, que fue distribuida a todos los actores federales y recibió 431 respuestas. El proceso resultó en 55 lineamientos priorizados, divididos en 6 áreas temáticas y 33 subtemas, seleccionados por votación según importancia, impacto y factibilidad


Assuntos
Argentina , Saúde Pública
8.
J Neuroendocrinol ; 32(3): e12836, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32062869

RESUMO

The present study aimed to determine whether an i.c.v. administration of allopregnanolone (ALLO) rapidly modifies the hypothalamic and ovarian 3ß-hydroxysteroid dehydrogenase (3ß-HSD) enzymatic activity and gene expression in in vivo and ex vivo systems in pro-oestrus (PE) and dioestrus I (DI) rats. Animals were injected with vehicle, ALLO, bicuculline or bicuculline plus ALLO and were then killed. In the in vivo experiment, the hypothalamus, ovaries and serum were extracted and analysed. In the ex vivo experiment, the superior mesenteric ganglion - ovarian nerve plexus - ovary system was extracted and incubated during 120 minutes at 37 ºC. The serum and ovarian compartment fluids were used to determine progesterone by radioimmunoanalysis. In the in vivo experiments, ALLO caused a decrease in hypothalamic and ovarian 3ß-HSD enzymatic activity during PE. During DI, ALLO increased hypothalamic and ovarian 3ß-HSD activity and gene expression. The ovarian 3ß-HSD activity increased in both stages in the ex vivo system; gene expression increased only during DI. ALLO induced an increase in serum progesterone only in D1 and in the ovarian incubation liquids in both stages. All findings were reversed by an injection of bicuculline before ALLO. Ovarian steroidogenic changes could be attributed to signals coming from ganglion neurones, which are affected by the acute central neurosteroid stimulation. The i.c.v. administration of ALLO via the GABAergic system altered 3ß-HSD activity and gene expression, modulating the neuroendocrine axis. The present study reveals the action that ALLO exerts on the GABAA receptor in both the central and peripheral nervous system and its relationship with hormonal variations. ALLO is involved in the "fine tuning" of neurosecretory functions as a potent modulator of reproductive processes in female rats.


Assuntos
3-Hidroxiesteroide Desidrogenases/metabolismo , Hipotálamo/efeitos dos fármacos , Neuroesteroides/administração & dosagem , Ovário/efeitos dos fármacos , Pregnanolona/administração & dosagem , Animais , Diestro/efeitos dos fármacos , Diestro/metabolismo , Feminino , Expressão Gênica/efeitos dos fármacos , Hipotálamo/enzimologia , Injeções Intraventriculares , Ovário/metabolismo , Proestro/efeitos dos fármacos , Proestro/metabolismo , Progesterona/sangue , Ratos
9.
J Steroid Biochem Mol Biol ; 196: 105492, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31614205

RESUMO

Ovarian carcinoma is one of the most common cause of death by gynecologic cancer. Several epidemiological and in vitro studies have shown controversial data about progesterone effects in ovarian cancer. Progesterone can be converted in its active metabolite, allopregnanolone, its effects in ovarian cancer are still unknown. Previously, we demonstrated that allopregnanolone modifies ovarian morphophysiology, being able to alter critical process of tumor development such as proliferation, apoptosis and angiogenesis. Taking into account these antecedents, we investigated the effect of progesterone and allopregnanolone on proliferation, apoptosis, clonogenic capacity and migration on two epithelial human ovarian cancer cell lines, IGROV-1 and SKOV-3. To this end, IGROV-1 and SKOV-3 cells were exposed to a range of progesterone and allopregnanolone concentrations (10-11 to 10-5 M) for 72 h. Proliferation was analyzed by MTT and Ki67 expression. Apoptosis was measured by immunocytochemistry of cleaved caspase 3. Clonogenic capacity was evaluated by counting colonies. Migration was analyzed by wound assay. We found that allopregnanolone increased proliferation and Ki67 expression respect to control on IGROV-1 cells, while expression of cleaved caspase 3 did not change in any cell line studied. IGROV-1 clonogenic capacity was also increased by allopregnanolone treatment. Both steroids, progesterone and allopregnanolone, increased IGROV-1 migration in a concentration dependent manner. None of the steroids tested modified SKOV-3 biological behavior analized. This is the first evidence that allopregnanolone, a progesterone metabolite, affects critical events in tumor development of human epithelial ovarian cancer. These results could have an impact in the future in clinic diagnosis, prognosis and treatment of ovarian cancer patients. The regulation of progesterone and allopregnanolone steroideogenesis and their molecular mechanisms might be considered as potential therapeutic tool in ovarian cancer.


Assuntos
Carcinoma Epitelial do Ovário/patologia , Proliferação de Células/efeitos dos fármacos , Neoplasias Ovarianas/patologia , Pregnanolona/farmacologia , Progesterona/farmacologia , Apoptose/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Progressão da Doença , Feminino , Humanos , Células Tumorais Cultivadas , Ensaio Tumoral de Célula-Tronco
10.
Reprod Biol Endocrinol ; 16(1): 35, 2018 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-29636114

RESUMO

BACKGROUND: Allopregnanolone is a neurosteroid synthesized in the central nervous system independently of steroidogenic glands; it influences sexual behavior and anxiety. The aim of this work is to evaluate the indirect effect of a single pharmacological dose of allopregnanolone on important processes related to normal ovarian function, such as folliculogenesis, angiogenesis and luteolysis, and to study the corresponding changes in endocrine profile and enzymatic activity over 4 days of the rat estrous cycle. We test the hypothesis that allopregnanolone may trigger hypothalamus - hypophysis - ovarian axis dysregulation and cause ovarian failure which affects the next estrous cycle stages. METHODS: Allopregnanolone was injected during the proestrous morning and then, the animals were sacrificed at each stage of the estrous cycle. Ovarian sections were processed to determine the number and diameter of different ovarian structures. Cleaved caspase 3, proliferating cell nuclear antigen, α-actin and Von Willebrand factor expressions were evaluated by immunohistochemistry. Luteinizing hormone, prolactin, estrogen and progesterone serum levels were measured by radioimmunoassay. The enzymatic activities of 3ß-hydroxysteroid dehydrogenase, 3α-hydroxysteroid oxidoreductase and 20α-hydroxysteroid dehydrogenase were determined by spectrophotometric assays. Two-way ANOVA followed by Bonferroni was performed to determine statistical differences between control and treated groups along the four stages of the cycle. RESULTS: The results indicate that allopregnanolone allopregnanolone decreased the number of developing follicles, while atretic follicles and cysts increased with no effects on normal cyclicity. Some cysts in treated ovaries showed morphological characteristics similar to luteinized unruptured follicles. The apoptosis/proliferation balance increased in follicles from treated rats. The endocrine profile was altered at different stages of the estrous cycle of treated rats. The angiogenic markers expression increased in treated ovaries. As regards corpora lutea, the apoptosis/proliferation balance and 20α-hydroxysteroid dehydrogenase enzymatic activity decreased significantly. Progesterone levels and 3ß-hydroxysteroid dehydrogenase enzymatic activity increased in treated rats. These data suggest that allopregnanolone interferes with steroidogenesis and folliculogenesis at different stages of the cycle. CONCLUSION: Allopregnanolone interferes with corpora lutea regression, which might indicate that this neurosteroid exerts a protective role over the luteal cells and prevents them from luteolysis. Allopregnanolone plays an important role in the ovarian pathophysiology.


Assuntos
Corpo Lúteo/efeitos dos fármacos , Ciclo Estral/efeitos dos fármacos , Folículo Ovariano/efeitos dos fármacos , Pregnanolona/farmacologia , Análise de Variância , Animais , Caspase 3/análise , Caspase 3/metabolismo , Sistema Endócrino/efeitos dos fármacos , Estrogênios/sangue , Feminino , Hidroxiesteroide Desidrogenases/metabolismo , Imuno-Histoquímica , Hormônio Luteinizante/sangue , Ovário/efeitos dos fármacos , Ovário/patologia , Oxirredutases/metabolismo , Progesterona/sangue , Prolactina/sangue , Antígeno Nuclear de Célula em Proliferação/análise , Antígeno Nuclear de Célula em Proliferação/metabolismo , Ratos
12.
Reproduction ; 2016 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-27777323

RESUMO

Allopregnanolone, a progesterone metabolite, is one of the best characterized neurosteroids. In a dose that mimics serum levels during stress, allopregnanolone inhibits sexual receptivity and ovulation and induces a decrease in luteinizing hormone levels. The aim of this work was to examine the effect of an intracerebroventricular administration of allopregnanolone on ovarian morphophysiology, serum and tissue levels of progesterone and estrogen, and enzymatic activity of 3ß-hydroxysteroid dehydrogenase, 20α-hydroxysteroid dehydrogenase and 3α-hydroxysteroid oxido-reductase in the ovary and in the medial basal hypothalamus on the morning of estrus. Ovarian morphology was analyzed under light microscopy. The hormone assays were performed by radioimmunoassay. The enzymatic activities were measured by spectrophotometric analysis. The morphometric analysis revealed that, in allopregnanolone-treated animals, the number of secondary and Graafian follicles was decreased while that of atretic follicles and cysts was significantly increased. Some cysts showed luteinized unruptured follicles. There were no differences in the number of tertiary follicles or corpora lutea in comparison with the corresponding control groups. In allopregnanolone-treated animals, progesterone serum levels were increased, while ovarian progesterone levels were decreased. Moreover, 3ß-HSD and 3α-HSOR enzymatic activities were increased in the medial basal hypothalamus while ovarian levels were decreased. The enzyme 20α-hydroxysteroid dehydrogenase showed the opposite profile. The results of this study showed that allopregnanolone interferes on ovarian steroidogenesis and ovarian morphophysiology in rats, providing a clear evidence for the role of this neurosteroid in the control of reproductive function under stress situations.

13.
Endocrine ; 40(1): 21-6, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21455639

RESUMO

LHRH release from hypothalamus is influenced by the neurotransmitter glutamate that acts, among others, on NMDA receptors present in LHRH neurons. On the other hand, the neurosteroid allopregnanolone can modulate the activity of specific neurotransmitter receptors and affect neurotransmitter release. We examined the role of allopregnanolone on in vitro LHRH and glutamate release from mediobasal hypothalamus and anterior preoptic area of ovariectomized rats with estrogen and progesterone replacement. Moreover, we evaluated whether the neurosteroid might act through modulation of NMDA receptors. Allopregnanolone induced an increase in LHRH release. This effect was reversed when the NMDA receptors were blocked by the NMDA antagonist 2-amino-7-phosphonoheptanoic acid (AP-7) indicating that this neurosteroid would interact with NMDA receptors. Moreover allopregnanolone induced an augment in K(+) evoked [(3)H]-glutamate release from mediobasal hypothalamus-anterior preoptic area explants and this effect was also reversed when NMDA receptors were blocked with AP-7. These results suggest an important physiologic function of allopregnanolone on the regulation of neuroendocrine function in female adult rats. Not only appears to be involved in enhancing LHRH release through modulation of NMDA receptors but also in the release of glutamate which is critical in the control of LHRH release.


Assuntos
Ácido Glutâmico/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/metabolismo , Neurotransmissores/farmacologia , Pregnanolona/farmacologia , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos , 2-Amino-5-fosfonovalerato/análogos & derivados , 2-Amino-5-fosfonovalerato/farmacologia , Animais , Terapia de Reposição de Estrogênios , Feminino , Hipotálamo/efeitos dos fármacos , Técnicas In Vitro , Modelos Animais , N-Metilaspartato/farmacologia , Ovariectomia , Área Pré-Óptica/efeitos dos fármacos , Área Pré-Óptica/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/fisiologia
14.
Endocrine ; 17(2): 77-83, 2002 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12041918

RESUMO

The effect of intracerebroventricular (icv) injection of allopregnanolone (5alpha-pregnan-3alpha-ol-20-one) on the dopaminergic and reproductive function in ovariectomized rats primed with estrogen and progesterone was investigated. Thirty minutes after icv allopregnanolone injection, the sexual receptivity, luteinizing hormone (LH) release, dopamine content, and release in the medial basal hypothalamus (MBH) and preoptic area (POA) were determined. After allopregnanolone injection, LH serum levels were reduced (p < 0.001) and lordosis behavior was inhibited (p < 0.005). Intracerebroventricular injection of bicuculline (a gamma-aminobutyric acidA [GABAA] antagonist) alone was ineffective. The injection of allopregnanolone plus bicuculline blocked the effects of allopregnanolone on sexual receptivity and on LH serum levels. At the same time, endogenous dopamine concentration in both the MBH and POA was augmented (p < 0.005 and p < 0.006, respectively) and the turnover rate decreased in both structures. Moreover, in vitro 3H-dopamine release from MBH and POA was lower in rats injected with allopregnanolone in comparison with vehicle-treated rats. These results suggest that allopregnanolone influences the dopaminergic mechanisms in female rats, which may, in turn, be responsible for the reduced reproductive activity. Allopregnanolone may exert its effects on sexual behavior through GABAA receptor modulation and a decrease in dopaminergic activity in the MBH and POA. These actions could explain the inhibition of LH release.


Assuntos
Dopamina/metabolismo , Hipotálamo/efeitos dos fármacos , Hormônio Luteinizante/sangue , Pregnanolona/farmacologia , Comportamento Sexual Animal/efeitos dos fármacos , Animais , Bicuculina/farmacologia , Feminino , Antagonistas GABAérgicos/farmacologia , Hipotálamo/metabolismo , Hormônio Luteinizante/metabolismo , Ovariectomia , Postura/fisiologia , Pregnanolona/administração & dosagem , Ratos , Ratos Sprague-Dawley , Comportamento Sexual Animal/fisiologia
15.
Cell Mol Neurobiol ; 22(4): 445-54, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12507393

RESUMO

1. The neurosteroids are compounds derived from steroid hormones and synthesized in the nervous system. They can modulate different neurotransmitter pathways. In previous work we demonstrated that progesterone modulates dopamine release induced by the glutamatergic agonist N-methyl-D-aspartic acid (NMDA). 2. The aim of this work was to evaluate a possible modulatory role of the progesterone metabolite allopregnanolone on NMDA-evoked [3H]dopamine release from corpus striatum slices obtained from cycling and ovariectomized female rats. 3. We used a dynamic superfusion method to evaluate the release of [3H]dopamine. Allopregnanolone at 50-600 nM was added to the superfusion buffer (Krebs-Ringer-bicarbonate-glucose. pH 7.4. with constant O2/CO2 gassing). The results are expressed as a percentage over basal [3H]dopamine loaded by the tissue. 4. Allopregnanolone (50 and 100 nM) increased the NMDA-evoked [3H]dopamine release from estrus rats. The remaining doses did not show significant changes in the pattern of release. This effect was not observed in diestrus rats. The ovariectomy abolished the facilitatory effect of allopregnanolone on NMDA-evoked 2 [3H]dopamine release. 5. Subcutaneous administration of exogenous estrogen (25 mg/rat) and progesterone (1 mg/rat) restored the facilitatory effect on dopaminergic input. 6. These results suggest that allopregnanolone is a neurosteroid able to modulate dopamine release in an ovarian-hormone-fluctuation-dependent manner and provide further support for a role of allopregnanolone as a modulator of glutamatergic-dopaminergic interaction in the corpus striatum.


Assuntos
Dopamina/metabolismo , Estrogênios/farmacologia , N-Metilaspartato/farmacologia , Pregnanolona/farmacologia , Progesterona/farmacologia , Animais , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/metabolismo , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Feminino , Ovariectomia , Ratos , Ratos Sprague-Dawley , Trítio
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...