Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.860
Filtrar
1.
Cien Saude Colet ; 27(9): 3615-3626, 2022 Sep.
Artigo em Português, Inglês | MEDLINE | ID: mdl-36000648

RESUMO

This study aimed to investigate the relationship between sexual maturation and anthropometric and blood pressure indicators in teenagers. This was a population-based cross-sectional study, conducted with 345 teenagers, aged 10 to 19 years, between 2018 and 2020. In this study, data referent to sociodemographic and anthropometric variables, blood pressure, and sexual maturation were collected. The data analysis was performed by applying the Principle Component Analysis (PCA), which generated three components and then tested the correlation between sexual maturation and the generated components. Most of the teenagers were female (53%), normotensive (66.1%), and with a normal weight (73%). A positive correlation was found between breast development and component 1 and component 2, as well as a negative correlation between the breasts and component 3. In the boys, the development of genitals and pubic hair was positively correlated with component 2 and inversely correlated with component 3. It could therefore be concluded that there is a relationship between sexual maturation and the anthropometric and blood pressure indicators, which proved to be representative variables for cardiovascular risk in teenagers, even if not in their entirety.


Objetivou-se investigar a relação entre a maturação sexual com indicadores antropométricos e pressóricos de adolescentes. Estudo transversal de base populacional, realizado entre 2018 e 2020, com 345 adolescentes de 10 a 19 anos. Coletou-se variáveis sociodemográficas e antropométricas, pressão arterial e maturação sexual. A análise dos dados foi feita por meio da Análise de Componentes Principais, que gerou três componentes e, posteriormente, testou-se a correlação entre a maturação sexual e os componentes gerados. A maioria dos adolescentes eram do sexo feminino (53%), normotensos (66,1%) e com peso normal (73%). Houve correlação positiva entre o desenvolvimento das mamas com o componente 1 e o componente 2, e correlação negativa entre mamas e o componente 3. Nos meninos, o desenvolvimento dos genitais e pelos pubianos estiveram positivamente correlacionados com o componente 2 e inversamente correlacionados com o componente 3. Conclui-se que existe relação entre a maturação sexual e os indicadores antropométricos e pressóricos, sendo variáveis representativas de risco cardiovascular em adolescentes, mesmo que não em sua totalidade.


Assuntos
Maturidade Sexual , Adolescente , Antropometria , Pressão Sanguínea , Estudos Transversais , Feminino , Humanos , Masculino , Maturidade Sexual/fisiologia
2.
Res Vet Sci ; 149: 94-101, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35777285

RESUMO

Puberty is part of physiological processes including growth, adrenarche, menarche, energy balance and metabolism. This study describes the dynamic between both metabolic and reproductive statutes during pubertal growth in Saharan breed sheep. Once weaned (3 months age), two lots of lambs are made up and each one receive a barley supplementation ration of 250 vs 500 g/head/day in addition to season's diet. Biometric measurements and blood samples are collected once a month from 3 to 12 months of age in order to evaluate biochemical and sexual hormonal status. Results show a significant weight gain and growth level in the double dose lot. Changes in biochemical parameters are closely related with age at least for glycemia and total proteinemia. Androgenic profile shows individual fluctuations (0.02 to 3.47 µg /ml) due to age, season and feeding ratio. In accordance with our findings, the diet effect is clearly evidenced between the two batches, it's noted that plasma concentration of androgens is the lowest (<0.30 ng /ml) at 3 months and increases to 0.53 vs 0.76 ng /ml between 4 and 6 months confirming the pre-pubertal phase. Also, biometric and biochemical parameters are tightly correlates with plasma androgen changes, depending on whether the animal be pubescent or not. In conclusion, although interesting this study shows no early puberty onset in the barley supplemented lambs as was reported in other sheep breeds; nevertheless, the testis activity as well as the body fitness have clearly be enhance. The synergy between biochemical profiles and biometric measurements explain the metabolic function of testicular androgens at puberty.


Assuntos
Androgênios , Hordeum , Animais , Biometria , Feminino , Masculino , Valor Nutritivo , Melhoramento Vegetal , Maturidade Sexual/fisiologia , Ovinos
3.
Physiol Behav ; 254: 113879, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-35705155

RESUMO

The present study examined the long-term effects of suppressing puberty with a GnRH agonist on reproductive physiology and behavior in female rats. We have recently reported that administration of the GnRH agonist leuprolide acetate (25 µg/kg) daily between postnatal day (PD) 25-50 delayed puberty and disrupted the development of copulatory behavior and sexual motivation in male rats. However, pilot data from our lab suggest that this low dose of leuprolide acetate (25 µg/kg) was not high enough to significantly delay puberty in female rats. Therefore, we injected female Long-Evans rats with leuprolide acetate at a higher dose (50 µg/kg) or 0.9% sterile saline, daily , starting on PD 25 and ending on PD 50. Vaginal opening was monitored daily starting on PD 30 for signs of pubertal onset and first estrous cycle. In addition, we measured estrous cyclicity starting approximately 2 weeks after the last injection of leuprolide (∼PD 64). Immediately after monitoring estrous cyclicity, the female rats were mated on their first day in behavioral estrus using the partner-preference paradigm, with and without physical contact (PD 95-110). We found that this dose of leuprolide (50 µg/kg) significantly delayed puberty; however, neither estrous cyclicity nor sexual motivation was significantly affected by periadolescent exposure to leuprolide. Together with our findings in male rats, these results add to our understanding of the developmental effects of chemically suppressing puberty in rats.


Assuntos
Ciclo Estral , Fármacos para a Fertilidade Feminina , Leuprolida , Comportamento Sexual Animal , Maturidade Sexual , Animais , Ciclo Estral/efeitos dos fármacos , Ciclo Estral/fisiologia , Estro , Feminino , Fármacos para a Fertilidade Feminina/farmacologia , Hormônio Liberador de Gonadotropina/agonistas , Leuprolida/farmacologia , Modelos Animais , Periodicidade , Ratos , Ratos Long-Evans , Comportamento Sexual Animal/efeitos dos fármacos , Comportamento Sexual Animal/fisiologia , Maturidade Sexual/efeitos dos fármacos , Maturidade Sexual/fisiologia
4.
J Neuroendocrinol ; 34(5): e13119, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35491543

RESUMO

In primates, the gonatotropin-releasing hormone (GnRH) neurosecretory system, consisting of GnRH, kisspeptin, and neurokinin B neurons, is active during the neonatal/early infantile period. During the late infantile period, however, activity of the GnRH neurosecretory system becomes minimal as a result of gonadal steroid independent central inhibition, and this suppressed GnRH neurosecretory state continues throughout the prepubertal period. At the initiation of puberty, the GnRH neurosecretory system becomes active again because of the decrease in central inhibition. During the progress of puberty, kisspeptin and neurokinin B signaling to GnRH neurons further increases, resulting in the release of gonadotropins and subsequent gonadal maturation, and hence puberty. This review further discusses potential substrates of central inhibition and subsequent pubertal modification of the GnRH neurosecretory system by the pubertal increase in steroid hormones, which ensures the regulation of adult reproductive function.


Assuntos
Kisspeptinas , Neurocinina B , Animais , Hormônio Liberador de Gonadotropina , Kisspeptinas/farmacologia , Hormônio Luteinizante , Neurocinina B/fisiologia , Primatas , Maturidade Sexual/fisiologia
6.
Growth Factors ; 40(1-2): 13-25, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35320050

RESUMO

Pheromones could promote hormone secretions and regulate sexual behavior. It was unclear whether multiparous pheromone could induce variations in puberty. The aim was to ascertain whether pheromone in urine of multiparous females induced central precocious puberty (CPP) in juvenile C57BL/6J females. The precocious puberty was examined by vaginal smear, lordosis reaction, HE stain, and ELISA analysis. Results suggested that the first vaginal opening and the first estrus were significantly earlier. The time interval of the first vaginal opening and estrus was significantly shortened. It was interesting that the first estrus was significantly correlated with the first vaginal opening and the time interval of the first estrus. In the first estrus, female lordosis reaction, the number of mature follicles, and the weight of the ovary and uterus significantly increased. The level of luteinizing hormones also significantly increased. Thus, multiparous pheromone can regulate sex hormone to induce CPP in juvenile C57BL/6J females.


Assuntos
Lordose , Feromônios , Animais , Feminino , Hormônio Luteinizante , Camundongos , Camundongos Endogâmicos C57BL , Feromônios/farmacologia , Feromônios/fisiologia , Maturidade Sexual/fisiologia
7.
J Neuroendocrinol ; 34(5): e13104, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35233849

RESUMO

To ensure the survival of the species, hypothalamic neuroendocrine circuits controlling fertility, which converge onto neurons producing gonadotropin-releasing hormone (GnRH), must respond to fluctuating physiological conditions by undergoing rapid and reversible structural and functional changes. However, GnRH neurons do not act alone, but through reciprocal interactions with multiple hypothalamic cell populations, including several glial and endothelial cell types. For instance, it has long been known that in the hypothalamic median eminence, where GnRH axons terminate and release their neurohormone into the pituitary portal blood circulation, morphological plasticity displayed by distal processes of tanycytes modifies their relationship with adjacent neurons as well as the spatial properties of the neurohemal junction. These alterations not only regulate the capacity of GnRH neurons to release their neurohormone, but also the activation of discrete non-neuronal pathways that mediate feedback by peripheral hormones onto the hypothalamus. Additionally, a recent breakthrough has demonstrated that GnRH neurons themselves orchestrate the establishment of their neuroendocrine circuitry during postnatal development by recruiting an entourage of newborn astrocytes that escort them into adulthood and, via signalling through gliotransmitters such as prostaglandin E2, modulate their activity and GnRH release. Intriguingly, several environmental and behavioural toxins perturb these neuron-glia interactions and consequently, reproductive maturation and fertility. Deciphering the communication between GnRH neurons and other neural cell types constituting hypothalamic neuroendocrine circuits is thus critical both to understanding physiological processes such as puberty, oestrous cyclicity and aging, and to developing novel therapeutic strategies for dysfunctions of these processes, including the effects of endocrine disruptors.


Assuntos
Astrócitos , Hormônio Liberador de Gonadotropina , Adulto , Astrócitos/metabolismo , Células Ependimogliais/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Humanos , Hipotálamo/metabolismo , Recém-Nascido , Neurônios/metabolismo , Maturidade Sexual/fisiologia
8.
Metabolism ; 129: 155141, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35074314

RESUMO

BACKGROUND: Perturbations in the timing of puberty, with potential adverse consequences in later health, are increasingly common. The underlying neurohormonal mechanisms are unfolded, but nutritional alterations are key contributors. Efforts to unveil the basis of normal puberty and its metabolic control have focused on mechanisms controlling expression of Kiss1, the gene encoding the puberty-activating neuropeptide, kisspeptin. However, other regulatory phenomena remain ill-defined. Here, we address the putative role of the G protein-coupled-receptor kinase-2, GRK2, in GnRH neurons, as modulator of pubertal timing via repression of the actions of kisspeptin, in normal maturation and conditions of nutritional deficiency. METHODS: Hypothalamic RNA and protein expression analyses were conducted in maturing female rats. Pharmacological studies involved central administration of GRK2 inhibitor, ßARK1-I, and assessment of gonadotropin responses to kisspeptin or phenotypic and hormonal markers of puberty, under normal nutrition or early subnutrition in female rats. In addition, a mouse line with selective ablation of GRK2 in GnRH neurons, aka G-GRKO, was generated, in which hormonal responses to kisspeptin and puberty onset were monitored, in normal conditions and after nutritional deprivation. RESULTS: Hypothalamic GRK2 expression increased along postnatal maturation in female rats, especially in the preoptic area, where most GnRH neurons reside, but decreased during the juvenile-to-pubertal transition. Blockade of GRK2 activity enhanced Ca+2 responses to kisspeptin in vitro, while central inhibition of GRK2 in vivo augmented gonadotropin responses to kisspeptin and advanced puberty onset. Postnatal undernutrition increased hypothalamic GRK2 expression and delayed puberty onset, the latter being partially reversed by central GRK2 inhibition. Conditional ablation of GRK2 in GnRH neurons enhanced gonadotropin responses to kisspeptin, accelerated puberty onset, and increased LH pulse frequency, while partially prevented the negative impact of subnutrition on pubertal timing and LH pulsatility in mice. CONCLUSIONS: Our data disclose a novel pathway whereby GRK2 negatively regulates kisspeptin actions in GnRH neurons, as major regulatory mechanism for tuning pubertal timing in nutritionally-compromised conditions.


Assuntos
Kisspeptinas , Desnutrição , Animais , Feminino , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/metabolismo , Kisspeptinas/genética , Desnutrição/metabolismo , Camundongos , Neurônios/metabolismo , Ratos , Receptores de Kisspeptina-1/metabolismo , Maturidade Sexual/fisiologia
9.
Reprod Biol ; 22(1): 100599, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35033902

RESUMO

The neuroendocrine mechanism underlying the sinusoidal wave nature of gonadotropin-releasing hormone pulse generator activity from infantile to adult age still needs to be meticulously defined. Direct inhibition of kisspeptin neurons by neuropeptide Y (NPY) and close intimacy between the two rekindle the importance of these two neuropeptides controlling reproductive axis activity. Thus, the present study was undertaken to decipher simultaneous fluctuations and to profile correlative changes in the relative expression of KISS1, NPY, and their receptor genes from the mediobasal hypothalamus of infant (n = 3), juvenile, pre-pubertal, and adult (n = 4 in each stage) male rhesus monkey (Macaca mulatta) by RT-qPCR. Significant elevation (p < 0.05-0.01) in KISS1 and KISS1R and low (p < 0.05) expression in NPY and NPY1R mRNA in the adult group as compared to the pre-pubertal group was observed. Moreover, significantly high (p < 0.05) expression of NPY and NPY1R mRNA with non-significant (p> 0.05) decline in KISS1 and KISS1R in pre-pubertal animals in comparison to infants describe inverse correlative age-associated changes during pubertal development. Current findings imply that NPY may contribute as a neurobiological brake for the dormancy of kisspeptin neurons before pubertal onset, while dwindling of this brake is likely to occasion kisspeptin dependent hypothalamic-pituitary-gonadal axis activation at puberty. These findings may help in the development of clinical and therapeutic strategies to regulate fertility in humans.


Assuntos
Envelhecimento , Kisspeptinas , Neuropeptídeo Y , Animais , Expressão Gênica , Hormônio Liberador de Gonadotropina/genética , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo , Kisspeptinas/genética , Kisspeptinas/metabolismo , Macaca mulatta/genética , Macaca mulatta/metabolismo , Masculino , Neuropeptídeo Y/genética , Neuropeptídeo Y/metabolismo , Maturidade Sexual/fisiologia
10.
J Neuroendocrinol ; 34(2): e12979, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-33904190

RESUMO

Puberty is a crucial biological process normally occurring at a specific time during the lifespan, during which sexual and somatic maturation are completed, and reproductive capacity is reached. Pubertal timing is not only determined by genetics, but also by endogenous and environmental cues, including nutritional and metabolic signals. During the last decade, we have learned much regarding the essential roles of kisspeptins and the neuropeptide pathways that converge on these neurones to modulate kisspeptin signalling, as well as neurokinin B and dynorphin, the co-transmitters of Kiss1 neurones in the arcuate nucleus, and the effects of melanocortins on puberty. Indeed, melanocortins are involved in transmitting the regulatory actions of metabolic cues on pubertal maturation. Intracellular metabolic sensors, such as the AMP-activated protein kinase and the fuel-sensing deacetylase SIRT1, have been shown to contribute to puberty. Further understanding of these signals and regulatory circuits will help uncover the intimacies of the central control of puberty, as well as how alterations in metabolic status, ranging from undernutrition to obesity, affect the pubertal process. Precocious puberty is rare and has a clear female predominance. Central precocious puberty (CPP) is diagnosed when premature activation of the hypothalamic-pituitary axis occurs. Its causes are heterogeneous, with alterations of the central nervous system being of special interest, and with environmental factors also playing a role in some cases. During the last decade, several mutations in different genes (including KISS1, KISS1R, MKRN3 and DLK1) that cause CPP have been discovered. Loss-of-function mutations in MKRN3 are the most common monogenic cause of CPP known to date. Here, we review and update what is known regarding the genotype-phenotype relationship in patients with CPP.


Assuntos
Puberdade Precoce , Feminino , Humanos , Kisspeptinas/metabolismo , Masculino , Melanocortinas , Puberdade Precoce/genética , Receptores de Kisspeptina-1/genética , Maturidade Sexual/fisiologia , Ubiquitina-Proteína Ligases
11.
Mol Cell Endocrinol ; 541: 111507, 2022 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-34785282

RESUMO

Bisphenol A (BPA) is a common endocrine disruptor and a high-fat diet (HFD) also affects fertility. However, little is known about the long-term consequences of simultaneous exposure to BPA and a HFD on reproductive health. Herein, we assessed the effects of maternal exposure to BPA in combination with a HFD on reproductive function in subsequent generations of female mice and evaluated its effects on the hypothalamic-pituitary-gonadal axis. We found that the combination of maternal exposure to BPA and a HFD led to increased urine BPA levels, precocious puberty, altered estrous cyclicity, decreased follicle numbers, and altered hypothalamic Kiss1 methylation status in F1 and F2 mice. Therefore, we demonstrated that maternal exposure to BPA in combination with a HFD exerts a trans-generational effect on female reproduction.


Assuntos
Compostos Benzidrílicos/toxicidade , Dieta Hiperlipídica/efeitos adversos , Genitália Feminina/fisiopatologia , Infertilidade Feminina/etiologia , Fenóis/toxicidade , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Animais , Gorduras na Dieta/efeitos adversos , Disruptores Endócrinos/toxicidade , Ciclo Estral/efeitos dos fármacos , Ciclo Estral/fisiologia , Feminino , Genitália Feminina/efeitos dos fármacos , Masculino , Exposição Materna/efeitos adversos , Camundongos , Camundongos Endogâmicos ICR , Gravidez , Efeitos Tardios da Exposição Pré-Natal/etiologia , Reprodução/efeitos dos fármacos , Reprodução/fisiologia , Maturidade Sexual/efeitos dos fármacos , Maturidade Sexual/fisiologia
12.
Neuroendocrinology ; 112(10): 998-1026, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34963114

RESUMO

INTRODUCTION: The kisspeptin gene Kiss1 is expressed in two hypothalamic areas: anteroventral periventricular nucleus/periventricular nucleus (AVPV/PeN) and arcuate nucleus (ARC), and also in gonads. Several pieces of evidence suggests that gamma-amino butyric acid B receptors (GABAB) signaling can regulate Kiss1 expression. Here, we inhibited GABAB signaling from PND2 to PND21 and evaluated the hypothalamic-pituitary-gonadal (HPG) axis. METHODS: BALB/c mice were treated on postnatal days 2-21 (PND2-PND21) with CGP55845 (GABAB antagonist) and evaluated in PND21 and adulthood: gene expression (qPCR) in the hypothalamus and gonads, hormones by radioimmunoassay, gonad histochemistry (H&E), puberty onset, and estrous cycles. RESULTS: At PND21, CGP inhibited Kiss1 and Tac2 and increased Pdyn and Gabbr1 in the ARC of both sexes and decreased Th only in female AVPV/PeN. Serum follicle-stimulating hormone (FSH) and testis weight were decreased in CGP-males, and puberty onset was delayed. In adults, Kiss1, Tac2, Pdyn, Pgr, Cyp19a1, and Gad1 were downregulated, while Gabbr1 was upregulated in the ARC of both sexes. In the AVPV/PeN, Kiss1, Th, Cyp19a1, and Pgr were decreased while Gad1 was increased in CGP-females, whereas Cyp19a1 was increased in CGP-males. Serum FSH was increased in CGP-males while prolactin was increased in CGP-females. Testosterone and progesterone were increased in ovaries from CGP-females, in which Kiss1, Cyp19a1, and Esr1 were downregulated while Hsd3b2 was upregulated, together with increased atretic and decreased ovulatory follicles. Testes from CGP-males showed decreased progesterone, increased Gabbr1, Kiss1, Kiss1r, and Esr2 and decreased Cyp19a1, and clear signs of seminiferous tubules atrophy. CONCLUSION: These results demonstrate that appropriate GABAB signaling during this critical prepubertal period is necessary for the normal development of the HPG axis.


Assuntos
Kisspeptinas , Progesterona , Animais , Núcleo Arqueado do Hipotálamo/metabolismo , Feminino , Hormônio Foliculoestimulante , Antagonistas GABAérgicos , Gônadas , Hipotálamo/metabolismo , Kisspeptinas/genética , Kisspeptinas/metabolismo , Masculino , Camundongos , Progesterona/metabolismo , Prolactina/metabolismo , Receptores de Kisspeptina-1/metabolismo , Maturidade Sexual/fisiologia , Testosterona/metabolismo , Desmame
13.
J Neuroendocrinol ; 33(12): e13063, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34866263

RESUMO

Androgens are steroid hormones that play a critical role in brain development and sexual maturation by acting upon both androgen receptors (AR) and estrogen receptors (ERα/ß) after aromatization. The contribution of estrogens from aromatized androgens in brain development and the central regulation of metabolism, reproduction, and behavior is well defined, but the role of androgens acting on AR has been unappreciated. Here, we map the sex specific expression of Ar in the adult and developing mouse brain. Postnatal days (PND) 12 and 21 were used to target a critical window of prepubertal development. Consistent with previous literature in adults, sex-specific differences in Ar expression were most profound in the bed nucleus of the stria terminalis (BST), medial amygdala (MEA) and medial preoptic area (MPO). Ar expression was also high in these areas at PND 12 and 21 in both sexes. In addition, we describe extra-hypothalamic and extra-limbic areas that show moderate, consistent and similar Ar expression in both sexes at both prepubertal time points. Briefly, Ar expression was observed in olfactory areas of the cerebral cortex, the hippocampus, several thalamic nuclei, and cranial nerve nuclei involved in autonomic sensory and motor function. To further characterize forebrain populations of Ar expressing neurons and determine whether they also coexpress estrogen receptors, we examined expression of Ar, Esr1 and Esr2 in prepubertal mice in selected nuclei. We found populations of neurons in the BST, MEA and MPO that coexpress Ar, but not Esr1 or Esr2, whereas others express a combination of the three receptors. Our findings indicate that various brain areas express Ar during prepubertal development and may play an important role in female neuronal development and physiology.


Assuntos
Encéfalo/metabolismo , Receptores Androgênicos/metabolismo , Maturidade Sexual/fisiologia , Animais , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/metabolismo , RNA Mensageiro/metabolismo , Receptores Androgênicos/genética , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , Caracteres Sexuais , Maturidade Sexual/genética , Distribuição Tecidual
14.
Sci Rep ; 11(1): 22688, 2021 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-34811385

RESUMO

Brain injuries induced by external forces are particularly challenging to model experimentally. In recent decades, the domestic pig has been gaining popularity as a highly relevant animal model to address the pathophysiological mechanisms and the biomechanics associated with head injuries. Understanding cognitive, motor, and sensory aspects of pig behavior throughout development is crucial for evaluating cognitive and motor deficits after injury. We have developed a comprehensive battery of tests to characterize the behavior and physiological function of the Yucatan minipig throughout maturation. Behavioral testing included assessments of learning and memory, executive functions, circadian rhythms, gait analysis, and level of motor activity. We applied traditional behavioral apparatus and analysis methods, as well as state-of-the-art sensor technologies to report on motion and activity, and artificial intelligent approaches to analyze behavior. We studied pigs from 16 weeks old through sexual maturity at 35 weeks old. The results show multidimensional characterization of minipig behavior, and how it develops and changes with age. This animal model may capitulate the biomechanical consideration and phenotype of head injuries in the developing brain and can drive forward the field of understanding pathophysiological mechanisms and developing new therapies to accelerate recovery in children who have suffered head trauma.


Assuntos
Comportamento Animal/fisiologia , Maturidade Sexual/fisiologia , Porco Miniatura/crescimento & desenvolvimento , Suínos/crescimento & desenvolvimento , Animais , Fenômenos Biomecânicos/fisiologia , Lesões Encefálicas , Ritmo Circadiano/fisiologia , Cognição/fisiologia , Modelos Animais de Doenças , Feminino , Marcha/fisiologia , Análise da Marcha/métodos , Masculino , Movimento/fisiologia , Teste de Campo Aberto/fisiologia
15.
Reprod Fertil Dev ; 33(18): 841-854, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34844663

RESUMO

With fewer than 7500 cheetahs remaining in the wild, ex situ cheetah populations serve as an insurance policy against extinction and a resource to study species' biology. This study aimed to identify the age of pubertal onset in ex situ female cheetahs using non-invasive faecal steroid hormone monitoring and body weights. Faecal samples from nine female cheetahs were collected two to three times weekly from 2 to 36months of age and body weights were recorded every 3months. Faecal oestrogen metabolites (FOM) and faecal glucocorticoid metabolites (FGM) were analysed using enzyme immunoassays and samples were categorised into 6-month intervals to compare endocrine characteristics. Faecal hormone and body weight data were analysed using generalised linear mixed models. Age was a significant predictor of mean and baseline FOM concentrations, number of FOM peaks, mean and maximum FOM peak concentrations and the number of cycles. Female cheetahs aged 24-30months exhibited a marked rise in mean FOM concentration and the number of FOM peaks and cycles increased with age until 24-30months. Females attained adult body weight by 21months of age. Mean and baseline FGM concentrations were highest at the 0-6 and 12-18months of age groups and did not follow the same FOM patterns. Based on body weight data, the FOM concentrations and peak patterning, females were considered pubertal from 24 to 30months of age. Characterisation of cheetah puberty has direct and significant implications for the improvement of management and reproductive success of cheetahs under human care. This information is particularly informative for identifying important windows of development, littermate dispersal and breeding introductions.


Assuntos
Peso Corporal/fisiologia , Estrogênios/metabolismo , Fezes/química , Glucocorticoides/análise , Maturidade Sexual/fisiologia , Acinonyx , Animais , Estrogênios/análise , Feminino
16.
Nat Neurosci ; 24(12): 1660-1672, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34795451

RESUMO

Neurons that produce gonadotropin-releasing hormone (GnRH), which control fertility, complete their nose-to-brain migration by birth. However, their function depends on integration within a complex neuroglial network during postnatal development. Here, we show that rodent GnRH neurons use a prostaglandin D2 receptor DP1 signaling mechanism during infancy to recruit newborn astrocytes that 'escort' them into adulthood, and that the impairment of postnatal hypothalamic gliogenesis markedly alters sexual maturation by preventing this recruitment, a process mimicked by the endocrine disruptor bisphenol A. Inhibition of DP1 signaling in the infantile preoptic region, where GnRH cell bodies reside, disrupts the correct wiring and firing of GnRH neurons, alters minipuberty or the first activation of the hypothalamic-pituitary-gonadal axis during infancy, and delays the timely acquisition of reproductive capacity. These findings uncover a previously unknown neuron-to-neural-progenitor communication pathway and demonstrate that postnatal astrogenesis is a basic component of a complex set of mechanisms used by the neuroendocrine brain to control sexual maturation.


Assuntos
Hormônio Liberador de Gonadotropina , Maturidade Sexual , Astrócitos/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/fisiologia , Neurônios/fisiologia , Maturidade Sexual/fisiologia
17.
Nature ; 599(7885): 436-441, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34732894

RESUMO

The state of somatic energy stores in metazoans is communicated to the brain, which regulates key aspects of behaviour, growth, nutrient partitioning and development1. The central melanocortin system acts through melanocortin 4 receptor (MC4R) to control appetite, food intake and energy expenditure2. Here we present evidence that MC3R regulates the timing of sexual maturation, the rate of linear growth and the accrual of lean mass, which are all energy-sensitive processes. We found that humans who carry loss-of-function mutations in MC3R, including a rare homozygote individual, have a later onset of puberty. Consistent with previous findings in mice, they also had reduced linear growth, lean mass and circulating levels of IGF1. Mice lacking Mc3r had delayed sexual maturation and an insensitivity of reproductive cycle length to nutritional perturbation. The expression of Mc3r is enriched in hypothalamic neurons that control reproduction and growth, and expression increases during postnatal development in a manner that is consistent with a role in the regulation of sexual maturation. These findings suggest a bifurcating model of nutrient sensing by the central melanocortin pathway with signalling through MC4R controlling the acquisition and retention of calories, whereas signalling through MC3R primarily regulates the disposition of calories into growth, lean mass and the timing of sexual maturation.


Assuntos
Desenvolvimento Infantil/fisiologia , Estado Nutricional/fisiologia , Puberdade/fisiologia , Receptor Tipo 3 de Melanocortina/metabolismo , Maturidade Sexual/fisiologia , Adolescente , Idoso de 80 Anos ou mais , Animais , Criança , Ciclo Estral/genética , Ciclo Estral/fisiologia , Feminino , Homozigoto , Humanos , Hipotálamo/citologia , Hipotálamo/fisiologia , Fator de Crescimento Insulin-Like I/metabolismo , Masculino , Melanocortinas/metabolismo , Menarca/genética , Menarca/fisiologia , Camundongos , Fenótipo , Puberdade/genética , Receptor Tipo 3 de Melanocortina/deficiência , Receptor Tipo 3 de Melanocortina/genética , Maturidade Sexual/genética , Fatores de Tempo , Aumento de Peso
18.
PLoS Biol ; 19(10): e3001434, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34673764

RESUMO

Productive transmission of malaria parasites hinges upon the execution of key transcriptional and posttranscriptional regulatory events. While much is now known about how specific transcription factors activate or repress sexual commitment programs, far less is known about the production of a preferred mRNA homeostasis following commitment and through the host-to-vector transmission event. Here, we show that in Plasmodium parasites, the NOT1 scaffold protein of the CAF1/CCR4/Not complex is duplicated, and one paralogue is dedicated for essential transmission functions. Moreover, this NOT1-G paralogue is central to the sex-specific functions previously associated with its interacting partners, as deletion of not1-g in Plasmodium yoelii leads to a comparable or complete arrest phenotype for both male and female parasites. We show that, consistent with its role in other eukaryotes, PyNOT1-G localizes to cytosolic puncta throughout much of the Plasmodium life cycle. PyNOT1-G is essential to both the complete maturation of male gametes and to the continued development of the fertilized zygote originating from female parasites. Comparative transcriptomics of wild-type and pynot1-g- parasites shows that loss of PyNOT1-G leads to transcript dysregulation preceding and during gametocytogenesis and shows that PyNOT1-G acts to preserve mRNAs that are critical to sexual and early mosquito stage development. Finally, we demonstrate that the tristetraprolin (TTP)-binding domain, which acts as the typical organization platform for RNA decay (TTP) and RNA preservation (ELAV/HuR) factors is dispensable for PyNOT1-G's essential blood stage functions but impacts host-to-vector transmission. Together, we conclude that a NOT1-G paralogue in Plasmodium fulfills the complex transmission requirements of both male and female parasites.


Assuntos
Estágios do Ciclo de Vida , Parasitos/crescimento & desenvolvimento , Parasitos/metabolismo , Plasmodium/crescimento & desenvolvimento , Plasmodium/metabolismo , Proteínas de Protozoários/metabolismo , Homologia de Sequência de Aminoácidos , Animais , Citosol/metabolismo , Feminino , Duplicação Gênica , Regulação da Expressão Gênica no Desenvolvimento , Células Germinativas/fisiologia , Masculino , Camundongos , Modelos Biológicos , Domínios Proteicos , Mapas de Interação de Proteínas , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Deleção de Sequência , Maturidade Sexual/fisiologia , Transcriptoma/genética , Zigoto/crescimento & desenvolvimento
19.
Cells ; 10(10)2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34685746

RESUMO

Postcopulatory sexual selection is credited as a principal force behind the rapid evolution of reproductive characters, often generating a pattern of correlated evolution between interacting, sex-specific traits. Because the female reproductive tract is the selective environment for sperm, one taxonomically widespread example of this pattern is the co-diversification of sperm length and female sperm-storage organ dimension. In Drosophila, having testes that are longer than the sperm they manufacture was believed to be a universal physiological constraint. Further, the energetic and time costs of developing long testes have been credited with underlying the steep evolutionary allometry of sperm length and constraining sperm length evolution in Drosophila. Here, we report on the discovery of a novel spermatogenic mechanism-sperm cyst looping-that enables males to produce relatively long sperm in short testis. This phenomenon (restricted to members of the saltans and willistoni species groups) begins early during spermatogenesis and is potentially attributable to heterochronic evolution, resulting in growth asynchrony between spermatid tails and the surrounding spermatid and somatic cyst cell membranes. By removing the allometric constraint on sperm length, this evolutionary innovation appears to have enabled males to evolve extremely long sperm for their body mass while evading delays in reproductive maturation time. On the other hand, sperm cyst looping was found to exact a cost by requiring greater total energetic investment in testes and a pronounced reduction in male lifespan. We speculate on the ecological selection pressures underlying the evolutionary origin and maintenance of this unique adaptation.


Assuntos
Estruturas Animais/anatomia & histologia , Drosophila/anatomia & histologia , Drosophila/fisiologia , Espermatozoides/fisiologia , Animais , Evolução Biológica , Masculino , Filogenia , Maturidade Sexual/fisiologia , Especificidade da Espécie , Testículo/anatomia & histologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...