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1.
Curr Opin Pediatr ; 35(4): 494-499, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37097290

RESUMO

PURPOSE OF REVIEW: The diagnostic criteria for polycystic ovary syndrome (PCOS) in adults may overdiagnose PCOS in adolescents. Since 2015, three guidelines have developed adolescent-specific diagnostic criteria and treatment recommendations. In this review, we compare and contrast the recommendations to assist in the practical application to clinical practice. RECENT FINDINGS: The guidelines agree that hyperandrogenism with menstrual irregularity be diagnostic criteria for PCOS in adolescents yet have slight differences in how to diagnose hyperandrogenism and in the definition of menstrual irregularity. The diagnostic option of 'at risk for PCOS' is recommended for those girls presenting with criteria within 3 years of menarche or with hyperandrogenism without menstrual irregularity, with re-assessment later in adolescence. Lifestyle changes is first line treatment. Treatment with combined oral contraceptives or metformin is suggested, using patient characteristics and preferences to guide decision-making. SUMMARY: PCOS is associated with long term reproductive and metabolic complications and will present during adolescence. Yet, diagnostic features may overlap with normal adolescent physiology. The recent guidelines strove to develop criteria to accurately identify girls with PCOS allowing early surveillance and treatment yet avoid overdiagnosis of normal adolescents.


Assuntos
Hiperandrogenismo , Metformina , Síndrome do Ovário Policístico , Feminino , Adulto , Adolescente , Humanos , Síndrome do Ovário Policístico/diagnóstico , Síndrome do Ovário Policístico/terapia , Síndrome do Ovário Policístico/complicações , Hiperandrogenismo/diagnóstico , Hiperandrogenismo/etiologia , Hiperandrogenismo/terapia , Distúrbios Menstruais/etiologia , Estilo de Vida , Metformina/uso terapêutico
2.
Curr Opin Endocrinol Diabetes Obes ; 27(1): 82-86, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31789832

RESUMO

PURPOSE OF REVIEW: To discuss treatments used to enhance growth in pediatric patients with short stature. RECENT FINDINGS: New data confirm the known efficacy of recombinant human growth hormone (rhGH) in growth hormone deficiency (GHD) and idiopathic short stature. The latest data from the Safety and Appropriateness of Growth hormone Treatment in Europe cohort did not indicate a long-term risk of malignancy in those treated for isolated GHD, but possibly increased risk in those with other diagnoses. Recombinant human insulin-like growth factor 1 is effective in treating patients with pregnancy-associated plasma protein A2 deficiency. Gonadotropin-releasing hormone agonists or aromatase inhibitor treatment to delay puberty remains controversial. They are more likely to augment adult height if combined with rhGH treatment in children already receiving rhGH. Preliminary data indicate that recombinant C-type natriuretic peptide (CNP) is safe in children and increases growth velocity upon 42 months of treatment in achondroplasia. SUMMARY: Recent data confirms previous data on rhGH efficacy and safety. Therapies to delay growth plate closure have greatest efficacy to augment height if combined with GH in select diagnoses. Recombinant CNP holds promise as a medical treatment for short stature associated with achondroplasia.


Assuntos
Endocrinologia , Transtornos do Crescimento/prevenção & controle , Transtornos do Crescimento/terapia , Hormônio do Crescimento Humano/deficiência , Adulto , Estatura/efeitos dos fármacos , Criança , Nanismo Hipofisário/tratamento farmacológico , Nanismo Hipofisário/epidemiologia , Endocrinologia/métodos , Endocrinologia/tendências , Europa (Continente)/epidemiologia , Transtornos do Crescimento/epidemiologia , Terapia de Reposição Hormonal/métodos , Terapia de Reposição Hormonal/tendências , Hormônio do Crescimento Humano/uso terapêutico , Humanos , Fator de Crescimento Insulin-Like I/uso terapêutico , Puberdade/efeitos dos fármacos , Puberdade/fisiologia , Proteínas Recombinantes/uso terapêutico
3.
Pediatr Endocrinol Rev ; 15(4): 280-290, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29806748

RESUMO

Care of transgender and gender diverse youth is complex and requires a multidisciplinary approach. Many transgender patients and providers feel the limited availability of affirming, knowledgeable professionals is a barrier to obtaining care. Such care can be provided through a clinic with providers from different disciplines who are trained in the unique care of transgender youth. In this paper, we discuss the care guidelines for transgender youth and the unresolved challenges that need to be addressed during the development of a transgender clinic. We describe our experience at Seattle Children's Hospital in the development of a multidisciplinary Gender Clinic which incorporates the expertise of social work, mental health professionals, pediatric endocrinology, adolescent medicine, and bioethics. Other institutions may build from our experience, with the ultimate goal of further decreasing health disparities for young transgender patients.


Assuntos
Endocrinologia , Pessoas Transgênero , Adolescente , Identidade de Gênero , Humanos
4.
Endocrinology ; 159(2): 1242-1252, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29315373

RESUMO

Female offspring of many species exposed to high doses of androgens in utero experience endocrine dysfunction during adulthood. The phenotype of offspring from females with prepregnancy hyperandrogenemia and impaired ovulation, however, has not been examined. We developed a mouse model of hyperandrogenemia by implanting a low-dose dihydrotestosterone (DHT) pellet 15 days before conception. Female offspring born to dams with hyperandrogenemia (DHT daughters) had delayed puberty (P < 0.05) with first estrus on postnatal day (PND) 41 compared with daughters from dams with physiological levels of DHT (non-DHT daughters, PND37.5). Serum follicle-stimulating hormone (FSH) levels in the DHT daughters were fourfold higher (P < 0.05) on PND21, and anti-Müllerian hormone levels were higher (P < 0.05) on PND26 than in non-DHT daughters (controls). DHT daughters showed an extended time in metestrus/diestrus and a shorter time in the proestrus/estrus phase compared with non-DHT daughters (P < 0.05). To examine ovarian response to gonadotropins, superovulation was induced and in vitro fertilization (IVF) was performed. Fewer numbers of oocytes were retrieved from the DHT daughters compared with non-DHT daughters (P < 0.05). At IVF, there was no difference in rates of fertilization or cleavage of oocytes from either group. There were fewer (P < 0.01) primordial follicles (6.5 ± 0.8 vs 14.5 ± 2.1 per ovary) in the ovaries of DHT daughters compared with non-DHT daughters. Daughters from hyperandrogenemic females exhibited elevated prepubertal FSH levels, diminished ovarian response to superovulation, impaired estrous cyclicity, delayed onset of puberty, and reduced ovarian reserve, suggesting that fetal androgen exposure had lasting effects on female reproductive function.


Assuntos
Hiperandrogenismo , Reserva Ovariana/fisiologia , Efeitos Tardios da Exposição Pré-Natal , Insuficiência Ovariana Primária/etiologia , Maturidade Sexual , Animais , Células Cultivadas , Doença Crônica , Feminino , Fertilidade , Hiperandrogenismo/complicações , Hiperandrogenismo/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia
5.
Horm Res Paediatr ; 86(6): 361-397, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27884013

RESUMO

BACKGROUND/AIMS: On behalf of the Drug and Therapeutics, and Ethics Committees of the Pediatric Endocrine Society, we sought to update the guidelines published in 2003 on the use of growth hormone (GH). Because idiopathic short stature (ISS) remains a controversial indication, and diagnostic challenges often blur the distinction between ISS, GH deficiency (GHD), and primary IGF-I deficiency (PIGFD), we focused on these three diagnoses, thereby adding recombinant IGF-I therapy to the GH guidelines for the first time. METHODS: This guideline was developed following the GRADE approach (Grading of Recommendations, Assessment, Development, and Evaluation). RESULTS: This guideline provides recommendations for the clinical management of children and adolescents with growth failure from GHD, ISS, or PIGFD using the best available evidence. CONCLUSION: The taskforce suggests that the recommendations be applied in clinical practice with consideration of the evolving literature and the risks and benefits to each individual patient. In many instances, careful review highlights areas that need further research.


Assuntos
Transtornos do Crescimento/tratamento farmacológico , Hormônio do Crescimento Humano/deficiência , Hormônio do Crescimento Humano/uso terapêutico , Fator de Crescimento Insulin-Like I/deficiência , Fator de Crescimento Insulin-Like I/uso terapêutico , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino
6.
PLoS One ; 10(3): e0119995, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25780937

RESUMO

Infertility associated with obesity is characterized by abnormal hormone release from reproductive tissues in the hypothalamus, pituitary, and ovary. These tissues maintain insulin sensitivity upon peripheral insulin resistance. Insulin receptor signaling may play a role in the dysregulation of gonadotropin-releasing hormone (GnRH) secretion in obesity, but the interdependence of hormone secretion in the reproductive axis and the multi-hormone and tissue dysfunction in obesity hinders investigations of putative contributing factors to the disrupted GnRH secretion. To determine the role of GnRH insulin receptor signaling in the dysregulation of GnRH secretion in obesity, we created murine models of diet-induced obesity (DIO) with and without intact insulin signaling in the GnRH neuron. Obese control female mice were infertile with higher luteinizing hormone levels and higher GnRH pulse amplitude and total pulsatile secretion compared to lean control mice. In contrast, DIO mice with a GnRH specific knockout of insulin receptor had improved fertility, luteinizing hormone levels approaching lean mice, and GnRH pulse amplitude and total secretion similar to lean mice. Pituitary responsiveness was similar between genotypes. These results suggest that in the obese state, insulin receptor signaling in GnRH neurons increases GnRH pulsatile secretion and consequent LH secretion, contributing to reproductive dysfunction.


Assuntos
Hormônio Liberador de Gonadotropina/metabolismo , Infertilidade Feminina/metabolismo , Receptor de Insulina/fisiologia , Animais , Feminino , Infertilidade Feminina/complicações , Hormônio Luteinizante/sangue , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Obesos , Obesidade/complicações , Obesidade/metabolismo , Ovário/metabolismo , Receptor de Insulina/metabolismo , Transdução de Sinais
7.
Mol Endocrinol ; 28(10): 1670-81, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25157703

RESUMO

Polycystic ovary syndrome is the major cause of infertility in reproductive aged women. Polycystic ovary syndrome is associated with high circulating levels of androgens and impaired metabolic function. The goal of this study was to understand how androgen signaling via the androgen receptor (AR) affects reproductive function. We knocked out the AR gene specifically in pituitary gonadotropes (PitARKO) to explore the role of androgen on the development of reproductive function in female mice. There was no difference in the age of puberty between control and PitARKO littermates, which was assessed by the ages of vaginal opening and first estrus. Cyclicity and fertility were also studied, and there was no significant difference between control and PitARKO mice. We observed a significant decrease in basal FSH serum and mRNA levels with no corresponding change in LH serum and mRNA levels. Although the numbers of litters born to control and PitARKO females were the same, the litter size was significantly smaller for PitARKO mice. The LH and FSH responses to ovariectomy was altered with reduced LH/FSH hormone and mRNA levels in PitARKO females. This reduction may be due to reduced expression of activin A/B and gnrhr. The preovulatory surge levels of LH and FSH were dramatically lower in PitARKO mice. The number of corpora lutea was decreased whereas the number of antral follicles was similar between control and PitARKO mice. Overall the pituitary AR contributes to the elaboration of the LH surge and normal reproductive function by regulating LH/FSH expression and secretion.


Assuntos
Hormônio Foliculoestimulante/metabolismo , Gonadotrofos/metabolismo , Hormônio Luteinizante/metabolismo , Ovulação/metabolismo , Receptores Androgênicos/genética , Animais , Corpo Lúteo/metabolismo , Ciclo Estral/metabolismo , Feminino , Fertilidade/fisiologia , Hormônio Foliculoestimulante/genética , Hormônio Luteinizante/genética , Camundongos , Camundongos Knockout , Ovário/metabolismo , Hipófise/metabolismo , Receptores Androgênicos/metabolismo , Maturidade Sexual/fisiologia
8.
Curr Pediatr Rep ; 1(2): 128-132, 2013 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-23772352

RESUMO

The availability of recombinant human growth hormone (rGH) for treatment of growth disorders has provided an unlimited supply for replacement in patients with growth hormone insufficiency but also for short stature due to Turner syndrome, renal failure, Prader-Willi syndrome, small for gestational age and idiopathic short stature. Considering the potential for side effects in the use of a growth promoting agent, the community of physicians and pharmaceutical manufacturers developed systematic methods to survey for short and long term effects. Recently published data from the National Cooperative Growth Study (NCGS), managed by Genentech, concluded that GH has a 'favorable profile'. In 2012, results from the European Union's Safety and Appropriateness of GH treatment in Europe (EU SAGhE) study about the long term mortality in GH treated patients were published in two separate manuscripts. This review will examine the issue of safety of rGH in order that practitioners are informed as they consider initiation of therapy with patients.

9.
Curr Opin Endocrinol Diabetes Obes ; 20(1): 50-5, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23222850

RESUMO

PURPOSE OF REVIEW: This review describes the most recent data about the effects of endocrine disrupting compounds (EDCs) on infant and early childhood growth and reproductive tract development as well as controversies in the field. RECENT FINDINGS: EDCs are present in pregnant women, young children and adolescents. Whether the level of exposure contributes to disease is an ongoing debate. Epidemiological studies suggest associations between prenatal EDC exposure and disease outcome, but animal studies using controlled EDC exposure have varying results with underlying mechanisms largely unknown. SUMMARY: Human exposure to EDCs is widespread; bisphenol A, phthalates and persistent organic pollutants are detectable in all age groups and geographical locations in the USA. Epidemiological and animal studies suggest that phthalates and bisphenol A have adverse effects on birth weight, promote development of childhood obesity and adversely affect male reproductive tract development. Differences in the interpretation of available studies underlie the disparate conclusions of scientific and regulatory body's panels on potential toxicological effects of EDCs at current levels of human exposure.


Assuntos
Disruptores Endócrinos/toxicidade , Exposição Ambiental/efeitos adversos , Retardo do Crescimento Fetal/induzido quimicamente , Exposição Materna/efeitos adversos , Obesidade/induzido quimicamente , Efeitos Tardios da Exposição Pré-Natal , Anormalidades Urogenitais/induzido quimicamente , Adolescente , Compostos Benzidrílicos/toxicidade , Criança , Pré-Escolar , Feminino , Retardo do Crescimento Fetal/epidemiologia , Política de Saúde , Humanos , Lactente , Masculino , Obesidade/epidemiologia , Praguicidas/toxicidade , Fenóis/toxicidade , Ácidos Ftálicos/toxicidade , Gravidez , Nascimento Prematuro/induzido quimicamente , Efeitos Tardios da Exposição Pré-Natal/epidemiologia , Estados Unidos/epidemiologia , Anormalidades Urogenitais/epidemiologia
10.
Cell Metab ; 12(3): 295-305, 2010 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-20816095

RESUMO

Obesity is associated with insulin resistance in metabolic tissues such as adipose, liver, and muscle, but it is unclear whether nonclassical target tissues, such as those of the reproductive axis, are also insulin resistant. To determine if the reproductive axis maintains insulin sensitivity in obesity in vivo, murine models of diet-induced obesity (DIO) with and without intact insulin signaling in pituitary gonadotrophs were created. Diet-induced obese wild-type female mice (WT DIO) were infertile and experienced a robust increase in luteinizing hormone (LH) after gonadotropin-releasing hormone (GnRH) or insulin stimulation. By contrast, both lean and obese mice with a pituitary-specific knockout of the insulin receptor (PitIRKO) exhibited reproductive competency, indicating that insulin signaling in the pituitary is required for the reproductive impairment seen in DIO and that the gonadotroph maintains insulin sensitivity in a setting of peripheral insulin resistance.


Assuntos
Infertilidade Feminina/etiologia , Obesidade/complicações , Hipófise/fisiologia , Receptor de Insulina/genética , Animais , Dieta , Ciclo Estral/fisiologia , Feminino , Hormônio Liberador de Gonadotropina/metabolismo , Infertilidade Feminina/genética , Insulina/metabolismo , Resistência à Insulina/fisiologia , Hormônio Luteinizante/metabolismo , Masculino , Camundongos , Camundongos Knockout , Hipófise/metabolismo , Receptor de Insulina/metabolismo , Reprodução/fisiologia , Transdução de Sinais/fisiologia
11.
J Clin Invest ; 120(8): 2900-9, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20628204

RESUMO

Pubertal onset, initiated by pulsatile gonadotropin-releasing hormone (GnRH), only occurs in a favorable, anabolic hormonal milieu. Anabolic factors that may signal nutritional status to the hypothalamus include the growth factors insulin and IGF-1. It is unclear which hypothalamic neuronal subpopulation these factors affect to ultimately regulate GnRH neuron function in puberty and reproduction. We examined the direct role of the GnRH neuron in growth factor regulation of reproduction using the Cre/lox system. Mice with the IR or IGF-1R deleted specifically in GnRH neurons were generated. Male and female mice with the IR deleted in GnRH neurons displayed normal pubertal timing and fertility, but male and female mice with the IGF-1R deleted in GnRH neurons experienced delayed pubertal development with normal fertility. With IGF-1 administration, puberty was advanced in control females, but not in females with the IGF-1R deleted in GnRH neurons, in control males, or in knockout males. These mice exhibited developmental differences in GnRH neuronal morphology but normal number and distribution of neurons. These studies define the role of IGF-1R signaling in the coordination of somatic development with reproductive maturation and provide insight into the mechanisms regulating pubertal timing in anabolic states.


Assuntos
Hormônio Liberador de Gonadotropina/fisiologia , Receptor IGF Tipo 1/fisiologia , Maturidade Sexual , Animais , Feminino , Fertilidade , Fator de Crescimento Insulin-Like I/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transdução de Sinais
12.
Biol Reprod ; 81(3): 488-96, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19439729

RESUMO

Mice lacking estrogen receptor alpha in the pituitary gonadotroph (PitEsr1KO) were generated to determine the physiologic role of pituitary estrogen signaling in the reproductive axis. PitEsr1KO female mice are subfertile or infertile and have elevated levels of serum luteinizing hormone (LH) and LH beta subunit gene expression, reflecting a lack of estrogen negative feedback effect on the gonadotroph. While serum LH values are elevated in PitEsr1KO mice, the degree of elevation is much less than that observed in ESR1-null mice, indicating that the hypothalamus must also have an important role in estrogen negative feedback. PitEsr1KO mice also demonstrate a defect in estrogen positive feedback, as surge LH values and estrous cyclicity are absent in these mice. Although sex steroid feedback in the reproductive axis is thought to involve discrete anatomic regions that mediate either a positive or negative estrogen effect, PitEsr1KO mice demonstrate novel evidence that localizes both estrogen positive feedback and estrogen negative feedback to the gonadotroph, which suggests that they may be mechanistically related.


Assuntos
Receptor alfa de Estrogênio/genética , Estrogênios/farmacologia , Retroalimentação Fisiológica/fisiologia , Infertilidade Feminina/genética , Hipófise/metabolismo , Animais , Receptor alfa de Estrogênio/metabolismo , Receptor beta de Estrogênio/genética , Receptor beta de Estrogênio/metabolismo , Estrogênios/sangue , Estrogênios/metabolismo , Ciclo Estral/sangue , Ciclo Estral/genética , Retroalimentação Fisiológica/efeitos dos fármacos , Feminino , Hormônios Esteroides Gonadais/sangue , Infertilidade Feminina/sangue , Infertilidade Feminina/metabolismo , Infertilidade Feminina/patologia , Hormônio Luteinizante/sangue , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Especificidade de Órgãos/genética , Ovário/metabolismo , Ovário/patologia
13.
Curr Opin Endocrinol Diabetes Obes ; 16(1): 1-4, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19115519

RESUMO

PURPOSE OF REVIEW: Puberty is the developmental process that culminates in reproductive capability. It is initiated by the release of gonadotropin-releasing hormone from specialized neurons of the hypothalamus to stimulate hormonal cascades and gonadal activation. The age of pubertal onset in girls may be younger than in previous decades, emphasizing the gaps in knowledge about pubertal onset and factors that modulate it. This review describes the state of the debate on the age of pubertal initiation, recent insights into the physiology of female puberty and its relationship to childhood obesity, and the regulation of gonadotropin-releasing hormone neurons at puberty. RECENT FINDINGS: Recent studies suggest that the average age of pubertal onset is decreasing in American girls, sparking controversy in defining the age at which puberty is considered precocious. Obese girls have hyperinsulinemia and hyperandrogenemia prepubertally, but it is unclear whether these factors play a role in the early onset of puberty in obese girls. The kisspeptin/G protein-coupled receptor 54 pathway is important for pubertal initiation; an activating mutation in the pathway has been associated with precocious puberty. SUMMARY: The recent trend toward obesity has been proposed to play a role in the cause of early puberty in girls. The molecular mechanisms that initiate puberty are slowly being elucidated, with the discovery of kisspeptin prompting a novel direction in reproductive research.


Assuntos
Puberdade/fisiologia , Fatores Etários , População Negra , Mama/crescimento & desenvolvimento , Criança , Feminino , Cabelo/crescimento & desenvolvimento , Humanos , Obesidade/epidemiologia , Estados Unidos , População Branca
14.
Ann N Y Acad Sci ; 1135: 19-28, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18574204

RESUMO

Puberty is the developmental process that culminates in reproductive capability and is the result of a complex series of molecular and physiological events. The release of gonadotropin-releasing hormone from specialized neurons of the hypothalamus begins the hormonal cascade that causes gonadal activation and the physical changes of puberty. Several factors have been proposed to influence the activation of the hypothalamus to trigger puberty, but the involved pathways have not been fully elucidated. The recent observations that the age of pubertal onset may be lowering in American girls calls attention to the lack of knowledge of modulating factors that affect the pubertal process. Genes necessary for puberty have been found by studying persons who do not achieve puberty; such studies have provided insights into the pathways necessary for pubertal development. A multidisciplinary focus is required to elucidate the complex mechanisms involved in the initiation and progression of puberty.


Assuntos
Hormônio Liberador de Gonadotropina/fisiologia , Hipotálamo/metabolismo , Menarca/fisiologia , Puberdade/fisiologia , Feminino , Humanos , Menarca/genética , Puberdade/genética , Transdução de Sinais
16.
Mol Cell Endocrinol ; 270(1-2): 64-72, 2007 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-17379398

RESUMO

Insulin increases gonadotropin-releasing hormone (GnRH) gene expression in in vitro models of GnRH neurons. Early growth response-1 (Egr-1) is a transcription factor that mediates the effect of insulin on target genes. In the GN11 cell line--an immortalized GnRH-secreting neuronal cell line--insulin maximally increases Egr-1 mRNA after 30min of treatment and Egr-1 protein and GnRH mRNA after 60min of treatment. Egr-1 small interfering RNA blocks the insulin-induced increase in GnRH promoter activity, measured as luciferase expression. Chromatin immunoprecipitation using Egr-1 antibody precipitates DNA in a proximal region of the GnRH promoter but not DNA in a distal region. Mutagenesis of a putative Egr-1 binding site within the proximal region blocks the insulin-induced increase in GnRH promoter activity. Thus, Egr-1 binds the GnRH promoter at a site between -67 and -76bp from the transcriptional start site to mediate the insulin-induced increase in GnRH gene transcription.


Assuntos
Proteína 1 de Resposta de Crescimento Precoce/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Hormônio Liberador de Gonadotropina/genética , Insulina/farmacologia , Regiões Promotoras Genéticas/genética , Animais , Sequência de Bases , Sítios de Ligação , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Hormônio Liberador de Gonadotropina/metabolismo , Humanos , Camundongos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Modelos Genéticos , Dados de Sequência Molecular , Mutação/genética , Ligação Proteica/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Fatores de Tempo
18.
Mol Cell Endocrinol ; 242(1-2): 42-9, 2005 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-16144737

RESUMO

In mammals, reproduction is acutely regulated by metabolic status. Insulin is an important nutritional signal from the periphery that may regulate the reproductive axis. To determine whether insulin acts directly on the GnRH neuron, we performed studies in mouse-derived GnRH-expressing cell lines. Both insulin receptor protein and mRNA were detected in these cells. A saturation radioligand binding assay revealed high affinity, low capacity binding sites for insulin in GnRH neurons. Insulin also stimulated GnRH promoter activity in GnRH neurons. This effect was blocked by pretreatment with the MEK inhibitor, PD98059, indicating a role for MAP kinase signaling. In transient transfection studies, insulin treatment stimulated expression of a 1250 bp mouse GnRH gene promoter fragment four-fold when compared to promoter activity in untreated cells. In contrast, insulin did not stimulate activity of a 587 bp fragment of the mGnRH gene promoter, indicating that the promoter elements mediating insulin stimulation of the GnRH promoter are located between -1250 and -587 bp. Our studies suggest that insulin may regulate reproductive function by direct effects on the GnRH neurons and specifically by stimulating GnRH gene expression.


Assuntos
Regulação da Expressão Gênica/efeitos dos fármacos , Hormônio Liberador de Gonadotropina/genética , Insulina/metabolismo , Sistema de Sinalização das MAP Quinases , Animais , Sítios de Ligação , Linhagem Celular , Clonagem Molecular , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Flavonoides/farmacologia , Genes Reporter/genética , Hormônio Liberador de Gonadotropina/metabolismo , Insulina/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Neurônios/metabolismo , Regiões Promotoras Genéticas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptor de Insulina/genética , Receptor de Insulina/metabolismo , Transfecção
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