Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.725
Filtrar
1.
Molecules ; 26(5)2021 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-33803091

RESUMO

Although melatonin has been extensively studied in animal reproduction, the mechanism of melatonin in puberty remains elusive. This study was designed to explore the effect of intraperitoneal administration of melatonin on puberty onset in female mice. The injection of melatonin into postnatal days 10 mice at a dose of 15 mg/kg accelerated the puberty onset in mice. Mechanistically, there was no difference in physical growth and serum Leptin levels after melatonin administration. Meanwhile, the serum levels of reproductive hormones involved in hypothalamic-pituitary-ovarian axis, such as FSH and estrogen level in serum were increased. The mRNA levels of GnRH and GnRHr were not affected by melatonin, while the expressions of FSHß in pituitary and Cyp19a1 in ovary were significantly up-regulated. In addition, melatonin still promoted FSH synthesis after ovariectomy. Furthermore, the enhanced activity of ERK1/2 signaling verified that the expression of FSHß increased in pituitary. We confirmed that melatonin promoted the FSH synthesis in pituitary, thereby increased serum estrogen levels and ultimately accelerated puberty onset. However, these effects of melatonin may be pharmacological due to the high dose. This study would help us to understand the functions of melatonin in pubertal regulation comprehensively.


Assuntos
Hormônio Foliculoestimulante/metabolismo , Melatonina/farmacologia , Maturidade Sexual/efeitos dos fármacos , Animais , Aromatase/metabolismo , China , Estrogênios/metabolismo , Feminino , Hormônio Liberador de Gonadotropina/metabolismo , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Injeções Intraperitoneais , Leptina/metabolismo , Hormônio Luteinizante/metabolismo , Melatonina/metabolismo , Camundongos , Ovário/efeitos dos fármacos , Hipófise/metabolismo , Sistema Hipófise-Suprarrenal/efeitos dos fármacos , Receptores LHRH/metabolismo , Maturidade Sexual/fisiologia
2.
Nutr. hosp ; 38(1): 29-35, ene.-feb. 2021. tab
Artigo em Inglês | IBECS | ID: ibc-198837

RESUMO

OBJECTIVE: to analyze the relationship of age at menarche and leptin with the metabolically healthy (MH) and metabolically unhealthy (MUH) phenotypes in adolescent girls in different body mass index (BMI) categories. METHOD: an observational and cross-sectional study consisting of 139 female adolescents attended to at the Adolescent Reference Center in Macaé, Rio de Janeiro. Menarche was classified as early (EM) when the first menstruation occurred at or before 11 years of age; normal menarche (NM) was categorized at ages 12 to 14; menarche was considered late (LM) when it occurred at age 15 or older. The factors required to ascertain the subjects' phenotype, as well as their leptin levels, weight, and height, were measured and their BMIs were calculated. The girls were classified as MH or MUH based on the NCEP-ATP III criteria as adapted for children and adolescents. RESULTS: 82 % (n = 114) of the girls were classified as MH and 18 % (n = 25) as MUH. Mean age at menarche was 11.79 ± 1.39 years. There was a higher prevalence of MUH amongst the girls who had EM (p = 0.04). A higher inadequacy of serum leptin concentrations was found in girls who had EM (p = 0.05) and in those classified as MUH (p = 0.01). The adolescents who were severely obese exhibited inadequate leptin levels (p < 0.01) and had gone through EM (p = 0.02). A total of 8.1 % (n = 7) of the normal-weight girls were classified as MUH, and 29.4 % (n = 5) of those who were severely obese were classified as MH (p < 0.01). CONCLUSION: early menarche and high serum leptin concentrations are related with the MUH phenotype in adolescent girls in different BMI categories


OBJETIVO: analizar la relación de la edad de la menarquia y los niveles de leptina con los fenotipos metabólicamente saludables (MS) y metabólicamente no saludables (MNS) en adolescentes de diferentes categorías de índice de masa corporal (IMC). MÉTODO: estudio observacional y transversal compuesto por 139 adolescentes de sexo feminino, atendidas en el Centro de Referencia para Adolescentes de Macaé, Río de Janeiro. La menarquia se clasificó como precoz (MP) cuando se produjo la primera menstruación a o antes de los 11 años de edad; la menarquia normal (MN) se clasificó como aquella sucedida a la edad de 12 a 14 años; la menarquia se consideró tardía (MT) cuando ocurrió a los 15 años o más. Se midieron los factores necesarios para determinar el fenotipo de los sujetos, y se midieron sus niveles de leptina, peso y altura, y se calculó su IMC. Las adolescentes se clasificaron como MS y MNS según los criterios de NCEP-ATP III, adaptados para niños y adolescentes. RESULTADOS: el 82 % (n = 114) de las adolescentes se clasificaron como MH y el 18 % (n = 25) como MUH. La edad media de la menarquia fue de 11,79 ± 1,39 años. Hubo una mayor prevalencia de MUH entre las adolescentes que tenían MP (p = 0,04). Se encontró una mayor insuficiencia de las concentraciones séricas de leptina en las adolescentes que tenían MP (p = 0,05) y en aquellas clasificadas como MNS (p = 0,01). Las adolescentes que eran severamente obesas exhibieron niveles inadecuados de leptina (p < 0,01) y habían pasado por una MP (p = 0,02). El 8,1 % (n = 7) de las adolescentes de peso normal se clasificaron como MNS y el 29,4 % (n = 5) de las que eran severamente obesas se clasificaron como MS (p < 0,01). CONCLUSIÓN: la menarquia temprana y las altas concentraciones séricas de leptina están relacionadas con el fenotipo MNS en las adolescentes de diferentes categorías de IMC


Assuntos
Humanos , Feminino , Criança , Adolescente , Menarca/fisiologia , Leptina/sangue , Densidade Óssea , Índice de Massa Corporal , Maturidade Sexual/fisiologia , Estudos Transversais , Antropometria , Pressão Sanguínea
3.
Toxicol Lett ; 342: 6-19, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33581290

RESUMO

2,2',4,4'-Tetrabromodiphenyl ether (BDE47), a flame retardant, is extensively distributed in the food chain. However, whether BDE47 affects Leydig cell development during prepuberty remains unclear. BDE47 was daily gavaged to 21-day-old Sprague-Dawley male rats with 0 (corn oil), 0.1, 0.2, and 0.4 mg/kg for 14 days. BDE47 did not affect the body weight or testis weight of rats. It significantly increased serum testosterone level at 0.4 mg/kg, but decreased luteinizing hormone (LH) level without affecting estradiol level. BDE47 induced Leydig cell hyperplasia (the number of CYP11A1-positive Leydig cells increased), and up-regulated the expression of Scarb1, Star, Hsd11b1, Pcna, and Ccnd1 in the testis. BDE47 significantly reduced p53 and p21 levels but increased CCND1 level. It also markedly increased the phosphorylation of AKT1, AKT2, ERK1/2, and CREB. BDE47 significantly up-regulated the expression of Scarb1, Star, and Hsd11b1 and stimulated androgen production by immature Leydig cells from rats under basal, LH, and 8Br-cAMP stimulated conditions at 100 nM in vitro. In conclusion, BDE47 increased Leydig cell number and up-regulated the expression of Scarb1 and Star, thereby leading to increased testosterone synthesis.


Assuntos
Éteres Difenil Halogenados/toxicidade , Células Intersticiais do Testículo/fisiologia , Maturidade Sexual/fisiologia , Células-Tronco/efeitos dos fármacos , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/genética , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/metabolismo , Animais , Células Cultivadas , Enzima de Clivagem da Cadeia Lateral do Colesterol/genética , Enzima de Clivagem da Cadeia Lateral do Colesterol/metabolismo , Relação Dose-Resposta a Droga , Hormônio Foliculoestimulante , Regulação da Expressão Gênica/efeitos dos fármacos , Éteres Difenil Halogenados/administração & dosagem , Éteres Difenil Halogenados/química , Hormônio Luteinizante , Masculino , Estrutura Molecular , Antígeno Nuclear de Célula em Proliferação/genética , Antígeno Nuclear de Célula em Proliferação/metabolismo , Ratos , Ratos Sprague-Dawley , Fatores de Transcrição SOX9/genética , Fatores de Transcrição SOX9/metabolismo
4.
Neurosci Lett ; 746: 135657, 2021 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-33482312

RESUMO

During puberty, sexual hormones induce crucial changes in neural circuit organization, leading to significant sexual dimorphism in adult behaviours. The ventrolateral division of the ventromedial nucleus of the hypothalamus (VMHvl) is the major neural site controlling the receptive component of female sexual behaviour, which is dependent on ovarian hormones. The inputs to the VMHvl, originating from the medial nucleus of the amygdala (MeA), transmit essential information to trigger such behaviour. In this study, we investigated the projection pattern of the MeA to the VMHvl in ovariectomized rats at early puberty. Six-week-old Sprague-Dawley rats were ovariectomized (OVX) and, upon reaching 90 days of age, were subjected to iontophoretic injections of the neuronal anterograde tracer Phaseolus vulgaris leucoagglutinin into the MeA. Projections from the MeA to the VMHvl and to other structures included in the neural circuit responsible for female sexual behaviour were analysed in the Control and OVX groups. The results of the semi-quantitative analysis showed that peripubertal ovariectomy reduced the density of intra-amygdalar fibres. The stereological estimates, however, failed to find changes in the organization of the terminal fields of nerve fibres from the MeA to the VMHvl in the adult. The present data show that ovariectomized rats during the peripubertal phase did not undergo significant changes in MeA fibres reaching the VMHvl; however, they suggest a possible effect of ovariectomy on MeA connectivity under amygdalar subnuclei.


Assuntos
Complexo Nuclear Corticomedial/metabolismo , Rede Nervosa/metabolismo , Ovariectomia/tendências , Maturidade Sexual/fisiologia , Núcleo Hipotalâmico Ventromedial/metabolismo , Fatores Etários , Animais , Complexo Nuclear Corticomedial/diagnóstico por imagem , Feminino , Imageamento Tridimensional/tendências , Rede Nervosa/diagnóstico por imagem , Vias Neurais/diagnóstico por imagem , Vias Neurais/metabolismo , Ovariectomia/efeitos adversos , Ratos , Ratos Sprague-Dawley , Núcleo Hipotalâmico Ventromedial/diagnóstico por imagem
5.
Gen Comp Endocrinol ; 300: 113636, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-33017581

RESUMO

Hyperactivity in the sympathetic nervous system has been shown to be related to the development of ovarian pathologies. In addition, obesity has been found to be associated with multiple reproductive anomalies and is considered a chronic stress condition of low intensity with changes in the peripheral sympathetic activity. Therefore, in the present study, we aimed to evaluate if the information reaching the ovaries through the superior ovarian nerve (SON) modifies the ovarian function of Zucker fatty rats. We performed a unilateral section of the SON at 32 days of age and autopsies were carried out on the day of the first vaginal estrus. The results showed that fatty animals do not ovulate on the day of the first vaginal estrus and exhibit an increase in catecholaminergic fibers and the presence of precystic structures in the ovaries, without changes in the onset of puberty or in the secretion of ovarian and hypophyseal hormones. We also found that the section of the right SON resulted in ovulation on the day of the first vaginal estrus, which was accompanied by a decrease in ovarian noradrenaline content. The section of the left SON caused a delay in puberty without changes in the rest of the parameters. These results provide functional evidence that the peripheral sympathetic innervation participates in the regulation of ovarian functions in an animal model of genetic obesity.


Assuntos
Tecido Nervoso/fisiologia , Ovário/inervação , Ovulação/fisiologia , Animais , Catecolaminas/metabolismo , Feminino , Ovário/anatomia & histologia , Ratos Zucker , Maturidade Sexual/fisiologia
6.
Toxicology ; 449: 152653, 2021 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-33309551

RESUMO

Bis(2-ethylhexyl) phthalate (DEHP) is a plasticizer used in several items, non-covalently bound to plastics and easily released, since metabolites were found in human matrices. DEHP is an endocrine disrupter and children are particularly vulnerable and susceptible to DEHP effects due to higher exposure levels and developmental stage. A juvenile toxicity study was performed to identify DEHP hazard and mode of action in Sprague-Dawley rats of both sexes during peri-pubertal period - corresponding to childhood phase - from weaning, post-natal day (PND) 23, to full sexual maturity (PND60); the dose levels of 0, 9, 21 and 48 mg/kg bw/day were derived from LIFE PERSUADED biomonitoring study in children. DEHP was administered by gavage for 28 days (5 days/week); timing of preputial separation and vaginal opening was observed during treatment. Histopathological analysis was performed on: adrenals, spleen, liver, thyroid and reproductive organs. The following serum biomarkers were assessed: estradiol, testosterone, anti-Mullerian hormone, tetraiodothyronine, thyroid stimulating hormone, adiponectin and leptin. Gene expression on hypothalamic-pituitary area was focused on follicle stimulating, luteinizing, and thyroid stimulating hormones. The results showed that main targets of DEHP during juvenile period were liver and metabolic system in both sexes, while sex-specific effects were recorded in reproductive system (male rats) and in thyroid (female rats). DEHP exposure during peri-pubertal period at dose levels derived from biomonitoring study in children can induce sex-specific imbalances identifying the juvenile animal model as a sound tool to identify hazards for a reliable risk assessment targeted to children.


Assuntos
Monitoramento Biológico/métodos , Dietilexilftalato/toxicidade , Reprodução/efeitos dos fármacos , Maturidade Sexual/efeitos dos fármacos , Glândula Tireoide/efeitos dos fármacos , Glândula Tireoide/metabolismo , Administração Oral , Fatores Etários , Animais , Animais Recém-Nascidos , Criança , Dietilexilftalato/administração & dosagem , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Plastificantes/administração & dosagem , Plastificantes/metabolismo , Plastificantes/toxicidade , Ratos , Ratos Sprague-Dawley , Reprodução/fisiologia , Maturidade Sexual/fisiologia
7.
Am J Physiol Endocrinol Metab ; 320(3): E415-E424, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33308013

RESUMO

Sex steroids are critical for skeletal development and maturation during puberty as well as for skeletal maintenance during adult life. However, the exact time during puberty when sex steroids have the highest impact as well as the ability of bone to recover from transient sex steroid deficiency is unclear. Surgical castration is a common technique to study sex steroid effects in rodents, but it is irreversible, invasive, and associated with metabolic and behavioral alterations. Here, we used a low dose (LD) or a high dose (HD) of gonadotropin-releasing hormone antagonist to either temporarily or persistently suppress sex steroid action in male mice, respectively. The LD group, a model for delayed puberty, did not show changes in linear growth or body composition, but displayed reduced trabecular bone volume during puberty, which fully caught up at adult age. In contrast, the HD group, representing complete pubertal suppression, showed a phenotype reminiscent of that observed in surgically castrated rodents. Indeed, HD animals exhibited severely impaired cortical and trabecular bone acquisition, decreased body weight and lean mass, and increased fat mass. In conclusion, we developed a rodent model of chemical castration that can be used as an alternative to surgical castration. Moreover, the transient nature of the intervention enables to study the effects of delayed puberty and reversibility of sex steroid deficiency.NEW & NOTEWORTHY We developed a rodent model of chemical castration, which can be used as an alternative to surgical castration. Moreover, the transient nature of the intervention enables to study the effects of delayed puberty and reversibility of sex steroid deficiency.


Assuntos
Desenvolvimento Ósseo , Osso e Ossos/fisiologia , Hormônios Esteroides Gonadais/deficiência , Hipogonadismo/patologia , Animais , Composição Corporal/efeitos dos fármacos , Desenvolvimento Ósseo/efeitos dos fármacos , Osso e Ossos/efeitos dos fármacos , Osso e Ossos/metabolismo , Hormônios Esteroides Gonadais/farmacologia , Hormônio Liberador de Gonadotropina/antagonistas & inibidores , Hormônio Liberador de Gonadotropina/farmacologia , Antagonistas de Hormônios/farmacologia , Hipogonadismo/complicações , Hipogonadismo/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Orquiectomia , Maturidade Sexual/fisiologia , Fatores de Tempo
8.
Life Sci ; 258: 118242, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32784056

RESUMO

AIMS: As the spermatogenesis process is targeted by cisplatin (Cis) that changes testicular morphology, alters sperm quality, and hence causes male infertility. This study investigated the possible therapeutic effects of l-carnitine (LC) on Cis impaired spermatogenesis's establishment during the prepubertal phase. MATERIALS AND METHODS: Ninety-six prepubertal Sprague Dawley male rats were divided into four groups. CONTROL GROUP: rats were injected with 0.9% saline solution intraperitoneally (i.p.). LC group: animals were injected for eight weeks, with 250 mg/kg/wk. LC (i.p.). Cis group: animals were injected with a single dose of 5 mg/kg Cis (i.p.). LC + Cis group: animals were pre-injected with LC 250 mg/kg 2 h before Cis injection. The rats were sacrificed at 37, 60, and 90 days old, and their testes were taken for biochemical, molecular, and histopathological studies. The motility, viability, morphology, and DNA fragmentation of sperm in adult rats were also measured. KEY FINDINGS: Group treated with LC and Cis showed an increase in antioxidant and hormonal activity compared to the Cis treated group in the pre and post-pubertal period. Moreover, there was an increase in sperm survival, motility, and DNA integrity. Furthermore, LC showed an increase in the anti-apoptotic and chromatin remodeling genes and a decrease in the pro-inflammatory genes. SIGNIFICANCE: LC could enhance the spermatogenesis process after exposure to Cis during the prepubertal phase by restoring the balance between reactive oxygen species and antioxidant activity, improving hormonal activity, sperm quality and DNA integrity, promoting protamination and blood-testis barrier integrity, and maintaining the testicular architecture.


Assuntos
Carnitina/farmacologia , Cisplatino/toxicidade , Infertilidade Masculina/prevenção & controle , Infertilidade Masculina/fisiopatologia , Maturidade Sexual/efeitos dos fármacos , Espermatogênese/efeitos dos fármacos , Animais , Antineoplásicos/toxicidade , Carnitina/uso terapêutico , Infertilidade Masculina/induzido quimicamente , Masculino , Ratos , Ratos Sprague-Dawley , Maturidade Sexual/fisiologia , Motilidade Espermática/efeitos dos fármacos , Motilidade Espermática/fisiologia , Espermatogênese/fisiologia
9.
PLoS One ; 15(8): e0236146, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760084

RESUMO

The smalltail shark, Carcharhinus porosus, was the most abundant elasmobranch species in fisheries off Brazil's northern coast (BNC) in the 1980s, but its population has been declining since the 1990s. For this reason, a demographic analysis is necessary to determine the extent of this decline and the fishing effect on the BNC's population. Therefore, we performed a stochastic demographic analysis of the population in the BNC, and considered its global center of abundance. Smalltail shark specimens (n = 937) were collected with gillnets in Maranhão state, eastern BNC, in the 1980s with sizes ranging between 29.6 and 120.0 cm total length. Most of the individuals (90.6%) caught were juveniles (< 6 years-old), and the mortality and exploitation rates showed that the species was overexploited (92.3% above the fishing mortality corresponding to the population equilibrium threshold). The smalltail shark's biological characteristics, such as slow growth and low fecundity, demonstrate that it is one of the least resilient species among similar sized coastal sharks in the region. All these factors yielded an annual decrease of 28% in the intrinsic population growth rate, resulting in a population decline of more than 90% in only 10 years, and much higher for the current period. This set of features comprising fishing recruitment occurring upon juveniles, overfishing, and intrinsically low resilience make the population unable to sustain fishing pressure and severely hamper biological recruitment, thus causing this drastic population decline. Furthermore, several local extinctions for this species in the northeastern and southeastern regions of Brazil highlight its concerning conservation scenario. Therefore, since similar fisheries characteristics occur throughout its distribution range, C. porosus fits the criteria E of the IUCN Red List for a critically endangered species and urgent conservation measures are needed to prevent its extinction in the near future.


Assuntos
Distribuição Animal , Espécies em Perigo de Extinção/estatística & dados numéricos , Pesqueiros/estatística & dados numéricos , Dinâmica Populacional/estatística & dados numéricos , Tubarões/fisiologia , Fatores Etários , Animais , Brasil , Monitorização de Parâmetros Ecológicos/estatística & dados numéricos , Espécies em Perigo de Extinção/tendências , Fertilidade/fisiologia , Pesqueiros/tendências , Dinâmica Populacional/tendências , Maturidade Sexual/fisiologia
10.
BMC Public Health ; 20(1): 1097, 2020 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-32660644

RESUMO

BACKGROUND: The onset of puberty and menarche is a potentially vulnerable time for girls. Educational and psychosocial competencies are regarded as essential tools that empower them to successfully navigate the adolescent years. The aim of this study is to evaluate to what extent school going girls are equipped with these key competencies, and how they vary across a given grade cohort. METHODS: Data was collected in Kilifi County, Kenya, from 140 public primary schools from grade 7, across three sub-counties. Bivariate and multivariate analyses were carried out to compare competency outcomes by age groups comprising 10-14 years and 15 year and above. Generalized estimating equations with robust standard errors was used where outcomes were measured as binary outcomes, and linear regression for continuous outcomes. Clustering was factored in at the school level and stratification at the subcounty level. Wilcoxon Rank sum test incorporating clustering effects was used where continuous outcomes were not normally distributed. RESULTS: A total of 3489 adolescent girls were interviewed with a mean age of 14 years (SD:1.5; min:10, max:21). Compared to the lower age group, girls in the higher age group were less likely to have ambitions of furthering their education beyond secondary school (odds ratio (OR):0.63 (95%CI:0.53, 0.74)), more likely to report not feeling confident enough to answer questions in class (OR:1.18 (95%CI:1.02, 1.36) and scored lower on their cognitive, math and literacy tests. They also displayed less positive gender norms (coefficient (coeff):-0.091 (95%CI:-0.16, - 0.022)) and were more likely to agree with intimate-partner violence in marriage (coeff:1.17 (95%CI:1.00, 1.37)). They however scored higher on the decision-making scale (coeff:0.36 (95%CI:0.13, 0.60)) and were more likely to be able to spontaneously name a method of modern contraception (OR:1.56 (95%CI:1.36, 1.80)). CONCLUSION: Large variability in age exits within a grade. Compared to older girls, younger girls were more likely to perform better on their educational and social competencies. In countries with large age ranges per grade, identifying the presence of educational and psychosocial competency variabilities will allow informed decisions to be made on how school-based interventions should be adapted to address the varying needs within a grade. TRIAL REGISTRATION: ISRCTN10894523 , date of registration: 22/08/2017. Retrospectively registered.


Assuntos
Sucesso Acadêmico , Instituições Acadêmicas/estatística & dados numéricos , Autoeficácia , Habilidades Sociais , Adolescente , Fatores Etários , Criança , Feminino , Humanos , Violência por Parceiro Íntimo/estatística & dados numéricos , Quênia , Maturidade Sexual/fisiologia , Adulto Jovem
11.
Crim Behav Ment Health ; 30(2-3): 117-131, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32535969

RESUMO

BACKGROUND: Early puberty is associated with higher than average risk of antisocial behaviour, both in girls and boys. Most studies of such association, however, have focused on psychosocial mediating and moderating factors. Few refer to coterminous hormonal measures. AIM: The aim of this review is to consider the role of hormonal markers as potential mediating or moderating factors between puberty timing and antisocial behaviour. METHOD: A systematic literature search was conducted searching Medline, Embase, Web of Science, Scopus, Psycinfo, Cochrane and Google Scholar. RESULTS: Just eight studies were found to fit criteria, all cross-sectional. Measurements were too heterogeneous to allow meta-analysis. The most consistent associations found were between adrenal hormones-both androgens and cortisol-which were associated with early adrenarche and antisocial behaviours in girls and later adrenarche and antisocial behaviour in boys. CONCLUSIONS: The findings from our review suggest that longitudinal studies to test bidirectional hormone-behaviour associations with early or late puberty would be worthwhile. In view of the interactive processes between hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axes, integrated consideration of the hormonal end products is recommended.


Assuntos
Comportamento do Adolescente/psicologia , Adrenarca/psicologia , Transtorno da Personalidade Antissocial/etiologia , Hormônios/sangue , Menarca/fisiologia , Puberdade/fisiologia , Maturidade Sexual/fisiologia , Adolescente , Comportamento do Adolescente/fisiologia , Adrenarca/fisiologia , Androgênios , Transtorno da Personalidade Antissocial/diagnóstico , Transtorno da Personalidade Antissocial/metabolismo , Criança , Feminino , Hormônios Esteroides Gonadais/sangue , Gonadotropinas Hipofisárias/sangue , Humanos , Hidrocortisona/metabolismo , Masculino , Fatores de Tempo
12.
PLoS One ; 15(6): e0234458, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32569264

RESUMO

We investigated the association of multiple single nucleotide polymorphisms (SNPs) with athlete status and power/speed performance in elite male youth soccer players (ESP) and control participants (CON) at different stages of maturity. ESP (n = 535; aged 8-23 years) and CON (n = 151; aged 9-26 years) were genotyped for 10 SNPs and grouped according to years from predicted peak-height-velocity (PHV), i.e. pre- or post-PHV, to determine maturity status. Participants performed bilateral vertical countermovement jumps, bilateral horizontal-forward countermovement jumps, 20m sprints and modified 505-agility tests. Compared to CON, pre-PHV ESP demonstrated a higher ACTN3 (rs1815739) XX ('endurance') genotype frequency distribution, while post-PHV ESP revealed a higher frequency distribution of the PPARA (rs4253778) C-allele, AGT (rs699) GG genotype and NOS3 (rs2070744) T-allele ('power' genotypes/alleles). BDNF (rs6265) CC, COL5A1 (rs12722) CC and NOS3 TT homozygotes sprinted quicker than A-allele carriers, CT heterozygotes and CC homozygotes, respectively. COL2A1 (rs2070739) CC and AMPD1 (rs17602729) GG homozygotes sprinted faster than their respective minor allele carrier counterparts in CON and pre-PHV ESP, respectively. BDNF CC homozygotes jumped further than T-allele carriers, while ESP COL5A1 CC homozygotes jumped higher than TT homozygotes. To conclude, we have shown for the first time that pre- and post-PHV ESP have distinct genetic profiles, with pre-PHV ESP more suited for endurance, and post-PHV ESP for power and speed (the latter phenotypes being crucial attributes for post-PHV ESP). We have also demonstrated that power, acceleration and sprint performance were associated with five SNPs, both individually and in combination, possibly by influencing muscle size and neuromuscular activation.


Assuntos
Atletas , Desempenho Atlético/fisiologia , Perfil Genético , Maturidade Sexual/fisiologia , Futebol , Aceleração , Actinina/genética , Adolescente , Estudos de Casos e Controles , Criança , Colágeno Tipo II/genética , Colágeno Tipo V/genética , Frequência do Gene , Humanos , Masculino , Força Muscular/genética , Polimorfismo de Nucleotídeo Único , Corrida/fisiologia , Adulto Jovem
13.
PLoS One ; 15(6): e0235140, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32574203

RESUMO

BACKGROUND: Due to improved treatment, there is an increasing focus on the reproductive potential of survivors of childhood cancer. Cytotoxic chemotherapy accelerates the decline in the number of primordial follicles within the mammalian ovary at all ages, but effects on the developmental potential of remaining oocytes following prepubertal cancer treatment are unclear. OBJECTIVES: To investigate whether cyclophosphamide (CY) exposure in the prepubertal period in female mice influences ovarian function and the functional competence of oocytes in adulthood. METHODS: This study used Swiss albino mice as the experimental model. Female mice were treated with 200 mg/kg CY on either postnatal day 14 (CY14), 21 (CY21) or 28 (CY28) i.e at a prepubertal and 2 young postpubertal ages. At 14 weeks of life, ovarian function, functional competence of oocytes, and embryo quality were assessed. RESULTS: The number of primordial follicles decreased significantly in CY14 and CY21 groups compared to control (p < 0.01). The number of oocytes from superovulated was 8.5 ± 1.4, 24.1 ± 2.9 and 26.8 ± 2.1 in CY14, CY21 and CY28 respectively which was significantly lower than control (50.2 ± 3.2; p < 0.001). In vitro culture of CY14 embryos demonstrated only 55.4% blastocyst formation (p < 0.0001) and reduced ability of inner cell mass (ICM) to proliferate in vitro (p < 0.05) at 120 and 216 h post insemination respectively. On the other hand, ICM proliferation was unaltered in 2 young postpubertal ages. CONCLUSION: Our results indicate long-term effects on the developmental competence of oocytes exposed to CY in early but not adult life. These data provide a mechanism whereby long-term fertility can be impaired after chemotherapy exposure, despite the continuing presence of follicles within the ovary, and support the need for fertility preservation in prepubertal girls before alkylating agent exposure.


Assuntos
Blastocisto/efeitos dos fármacos , Ciclofosfamida/farmacologia , Desenvolvimento Embrionário/efeitos dos fármacos , Reserva Ovariana/efeitos dos fármacos , Maturidade Sexual/fisiologia , Animais , Hormônio Antimülleriano/sangue , Antineoplásicos Alquilantes/farmacologia , Blastocisto/citologia , Blastocisto/fisiologia , Peso Corporal/efeitos dos fármacos , Peso Corporal/fisiologia , Proliferação de Células/efeitos dos fármacos , Ciclofosfamida/administração & dosagem , Embrião de Mamíferos/efeitos dos fármacos , Embrião de Mamíferos/embriologia , Desenvolvimento Embrionário/fisiologia , Feminino , Fertilidade/efeitos dos fármacos , Fertilidade/fisiologia , Camundongos , Oócitos/efeitos dos fármacos , Oócitos/fisiologia , Tamanho do Órgão/efeitos dos fármacos , Reserva Ovariana/fisiologia , Ovário/anatomia & histologia , Ovário/citologia , Ovário/efeitos dos fármacos , Fatores de Tempo
14.
J Sports Sci ; 38(20): 2298-2306, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32543283

RESUMO

This study estimated upper and lower limb bone mineral content (BMC) and bone area (BA) in 48 children tennis players (24 boys, 24 girls) aged 7-13 years. The sample comprised four age groups (8.2 ± 0.44, 9.5 ± 0.13, 10.5 ± 0.33, 12.2 ± 0.58). BMC and BA were measured via DXA, and sexual maturity by the Tanner scale, then used as a binary: prepubertal vs peripubertal. Total training time (TTT) included all playing years. Arms were asymmetric and legs symmetric. Boys were more asymmetric than girls in BMC (18% vs 13%) and BA (11% vs 8%). Pre-pubertal children were less asymmetric than peri-pubertal in BMC (14% vs 18%) and in BA (9.4% vs 10%). Bone growth changed with age and TTT markedly better in the dominant arm. The linear combination of TTT, sex, and maturity binary extracted 59% of BMC asymmetry and only 21% of BA asymmetry. For both bone parameters the sex effect was significant only for the pre-pubertal children. Training time constitutes the best predictor of bone asymmetry compared to age, sex, and maturity; when adequate, playing arm bone hypertrophy may be detectable at the age of 7-8 years. These results have health and performance implications.


Assuntos
Densidade Óssea , Desenvolvimento Ósseo/fisiologia , Extremidade Inferior/fisiologia , Condicionamento Físico Humano/fisiologia , Maturidade Sexual/fisiologia , Tênis/fisiologia , Extremidade Superior/fisiologia , Adolescente , Fatores Etários , Criança , Feminino , Humanos , Masculino , Puberdade/fisiologia , Análise de Regressão , Fatores Sexuais , Fatores de Tempo
15.
Psychopharmacology (Berl) ; 237(8): 2469-2483, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32445054

RESUMO

RATIONALE: MK801, like other NMDA receptor open-channel blockers (e.g., ketamine and phencyclidine), increases the locomotor activity of rats and mice. Whether this behavioral effect ultimately relies on monoamine neurotransmission is of dispute. OBJECTIVE: The purpose of this study was to determine whether these psychopharmacological effects and underlying neural mechanisms vary according to sex and age. METHODS: Across four experiments, male and female preweanling and adolescent rats were pretreated with vehicle, the monoamine-depleting agent reserpine (1 or 5 mg/kg), the dopamine (DA) synthesis inhibitor ∝-methyl-DL-p-tyrosine (AMPT), the serotonin (5-HT) synthesis inhibitor 4-chloro-DL-phenylalanine methyl ester hydrochloride (PCPA), or both AMPT and PCPA. The locomotor activity of preweanling and adolescent rats was then measured after saline or MK801 (0.3 mg/kg) treatment. RESULTS: As expected, MK801 increased the locomotor activity of all age groups and both sexes, but the stimulatory effects were significantly less pronounced in male adolescent rats. Preweanling rats and adolescent female rats were more sensitive to the effects of DA and 5-HT synthesis inhibitors, as AMPT and PCPA caused only small reductions in the MK801-induced locomotor activity of male adolescent rats. Co-administration of AMPT+PCPA or high-dose reserpine (5 mg/kg) treatment substantially reduced MK801-induced locomotor activity in both age groups and across both sexes. CONCLUSIONS: These results, when combined with other recent studies, show that NMDA receptor open-channel blockers cause pronounced age-dependent behavioral effects that can vary according to sex. The neural changes underlying these sex and age differences appear to involve monoamine neurotransmission.


Assuntos
Maleato de Dizocilpina/farmacologia , Dopamina/fisiologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Locomoção/fisiologia , Serotonina/fisiologia , Maturidade Sexual/fisiologia , Inibidores da Captação Adrenérgica/farmacologia , Fatores Etários , Animais , Animais Recém-Nascidos , Antagonistas de Dopamina/farmacologia , Feminino , Locomoção/efeitos dos fármacos , Masculino , Ratos , Ratos Sprague-Dawley , Antagonistas da Serotonina/farmacologia , Fatores Sexuais , Maturidade Sexual/efeitos dos fármacos
16.
Croat Med J ; 61(2): 107-118, 2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-32378377

RESUMO

AIM: To evaluate the effects of maturation and sex on glucose metabolism during glucose tolerance (GTT) and insulin tolerance tests (ITT) in young and adult male and female rats by using two different approaches - the conventional, which uses area under the curve and glucose curve, and mathematical modeling that identifies parameters necessary for determining the function that models glucose metabolism. METHODS: Male and female rats at 3.5 and 12 months of age underwent standard GTT and ITT after overnight fasting. The parameters were identified by using Mathematica-module NonlinearModelFit [] for experimentally obtained data. RESULTS: When data were statistically analyzed, both sexes and age groups had similar glucose and insulin tolerance. In the mathematical model of GTT, parameters describing the rate of glucose concentration increase G'(0) and decrease G'I multiplied with maturation, with a concomitant decrease in the time point (tmax, tI) of reaching maximum and minimum glucose concentration (Gmax, G0). The mathematical model of ITT for males was independent of age, unlike of that for females, which had increased G'(0) and G'I, and more quickly recovered from hypoglycemia after maturation. CONCLUSION: The mathematical model revealed female susceptibility to large glucose excursions, which are better reflected by ITT in young animals and by GTT in adults.


Assuntos
Glicemia , Insulina , Maturidade Sexual/fisiologia , Envelhecimento/fisiologia , Animais , Glicemia/metabolismo , Glicemia/fisiologia , Feminino , Insulina/sangue , Insulina/metabolismo , Insulina/fisiologia , Masculino , Modelos Teóricos , Ratos
17.
Genet Sel Evol ; 52(1): 28, 2020 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-32460805

RESUMO

BACKGROUND: In tropically-adapted beef heifers, application of genomic prediction for age at puberty has been limited due to low prediction accuracies. Our aim was to investigate novel methods of pre-selecting whole-genome sequence (WGS) variants and alternative analysis methodologies; including genomic best linear unbiased prediction (GBLUP) with multiple genomic relationship matrices (MGRM) and Bayesian (BayesR) analyses, to determine if prediction accuracy for age at puberty can be improved. METHODS: Genotypes and phenotypes were obtained from two research herds. In total, 868 Brahman and 960 Tropical Composite heifers were recorded in the first population and 3695 Brahman, Santa Gertrudis and Droughtmaster heifers were recorded in the second population. Genotypes were imputed to 23 million whole-genome sequence variants. Eight strategies were used to pre-select variants from genome-wide association study (GWAS) results using conditional or joint (COJO) analyses. Pre-selected variants were included in three models, GBLUP with a single genomic relationship matrix (SGRM), GBLUP MGRM and BayesR. Five-way cross-validation was used to test the effect of marker panel density (6 K, 50 K and 800 K), analysis model, and inclusion of pre-selected WGS variants on prediction accuracy. RESULTS: In all tested scenarios, prediction accuracies for age at puberty were highest in BayesR analyses. The addition of pre-selected WGS variants had little effect on the accuracy of prediction when BayesR was used. The inclusion of WGS variants that were pre-selected using a meta-analysis with COJO analyses by chromosome, fitted in a MGRM model, had the highest prediction accuracies in the GBLUP analyses, regardless of marker density. When the low-density (6 K) panel was used, the prediction accuracy of GBLUP was equal (0.42) to that with the high-density panel when only six additional sequence variants (identified using meta-analysis COJO by chromosome) were included. CONCLUSIONS: While BayesR consistently outperforms other methods in terms of prediction accuracies, reasonable improvements in accuracy can be achieved when using GBLUP and low-density panels with the inclusion of a relatively small number of highly relevant WGS variants.


Assuntos
Bovinos/genética , Genômica/métodos , Maturidade Sexual/genética , Animais , Teorema de Bayes , Cruzamento , Feminino , Genoma/genética , Estudo de Associação Genômica Ampla , Genótipo , Fenótipo , Polimorfismo de Nucleotídeo Único/genética , Maturidade Sexual/fisiologia , Sequenciamento Completo do Genoma/métodos
18.
Behav Processes ; 175: 104122, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32259623

RESUMO

Nutritional stress during the earliest stages of an animal's life can have long-term effects on its behavior and reproductive performance, but the effects of brief periods of nutritional stress later in life are less well-studied. We manipulated female diet in Narnia femorata (Hemiptera: Coreidae) and investigated to what extent nutritional stress during sexual maturation affects subsequent sexual behavior and long-term offspring production. We show that nutritional stress at this key point during early adulthood can have lasting effects on reproduction, impairing long-term offspring production despite the subsequent return of good nutrition. These results demonstrate that nutritional availability during late stages of development, in young adults, can be crucial to future fitness. We found no effect of temporary nutritional stress on female receptivity to mating or attractiveness to males; although females that were less receptive also produced fewer offspring in the next month. Overall, we demonstrate that even brief periods of nutritional deprivation late in development can have drastic long-term effects, apparently beyond compensation, and despite a good early nutritional environment.


Assuntos
Fenômenos Fisiológicos da Nutrição Animal/fisiologia , Reprodução/fisiologia , Comportamento Sexual Animal/fisiologia , Maturidade Sexual/fisiologia , Estresse Fisiológico/fisiologia , Animais , Feminino , Hemípteros
19.
Sci Rep ; 10(1): 6664, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32313091

RESUMO

We examine the extent to which intrinsic and extrinsic factors influence reproductive phenology in male bats at the population level. Using data from thirteen breeding seasons (2006-2018), encompassing the reproductive histories of 1546 Myotis daubentonii and 530 M. nattereri males, we compare rates of sexual maturation and the temporal distribution of phases of spermatogenesis between juvenile (born that season) and adult (born in previous seasons) males. We found that (i) higher proportions of M. daubentonii (50.81%) than M. nattereri (12.85%) became sexually mature as juveniles, (ii) the proportion of juveniles in reproductive condition per annum was influenced by spring weather conditions, (iii) in both species males that reached puberty as juveniles had higher body mass, on average, than immature juveniles, (iv) older males (aged ≥4 years old) commenced spermatogenesis earlier than young adult males (aged 1-3 years old), whilst juveniles that commenced spermatogenesis did so later in the year than adults, in both species, and (v) M. daubentonii commenced and completed spermatogenesis earlier than M. nattereri in the equivalent age class. Our findings suggest that selection pressure exists for early mating readiness and synchronisation with female receptivity.


Assuntos
Quirópteros/fisiologia , Reprodução/fisiologia , Maturidade Sexual/fisiologia , Espermatogênese/fisiologia , Animais , Peso Corporal/fisiologia , Feminino , Masculino , Estações do Ano , Reino Unido , Tempo (Meteorologia)
20.
Sci Rep ; 10(1): 6636, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32313106

RESUMO

The effect of excessive gestational weight gain (EGWG) is related to adverse health outcomes in the offspring; however, its effect on the daughters' breast density is unclear. We aimed to assess the association between EGWG and daughters' breast composition (% of fibroglandular volume (%FGV) and absolute fibroglandular volume (AFGV)) at Tanner stage 4 (Tanner B4)). We included 341 girls and their mothers from an ongoing cohort of low-income Chilean girls born from 2002-2003. Maternal gestational weight gain was self-reported in 2007, and breast density by digital mammography was measured in 2010. Weight, height and breast composition by dual X-ray absorptiometry (DXA) were measured in daughters at Tanner B4. Logistic regression models were run to assess the association between EGWG and the 80th percentile of %FGV and AFGV. Mean gestational weight gain was 13.7 kg (SD = 6.9 kg). Women with pregestational overweight or obesity exceeded the recommended gestational weight gain (58.8% vs. 31.8%, respectively). Daughters of women who had EGWG had higher levels of AFGV (OR: 2.02; 95%CI 1.16-3.53) at Tanner B4, which could be explained by metabolic and hormonal exposure in utero. However, we did not observe an association with %FGV.


Assuntos
Densidade da Mama/fisiologia , Ganho de Peso na Gestação , Glândulas Mamárias Humanas/diagnóstico por imagem , Obesidade/diagnóstico por imagem , Maturidade Sexual/fisiologia , Absorciometria de Fóton , Adolescente , Adulto , Criança , Chile , Feminino , Humanos , Padrões de Herança , Modelos Logísticos , Estudos Longitudinais , Glândulas Mamárias Humanas/metabolismo , Mamografia , Mães , Núcleo Familiar , Obesidade/metabolismo , Obesidade/fisiopatologia , Gravidez
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...