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1.
Endocrinology ; 161(1)2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31875912

RESUMO

Changes in gonadotropin-releasing hormone (GnRH) release frequency from the brain help drive reproductive cycles. In polycystic ovary syndrome (PCOS), persistent high GnRH/luteinizing hormone (LH) frequency disrupts cycles and exacerbates hyperandrogenemia. Adult prenatally-androgenized (PNA) mice exhibit increased GnRH neuron firing rate, elevated ovarian androgens, and disrupted cycles, but before puberty, GnRH neuron activity is reduced in PNA mice compared with controls. We hypothesized that ovarian feedback mediates the age-dependent change in GnRH neuron firing rate in PNA vs control mice. Extracellular recordings of green fluorescent protein (GFP)-identified GnRH neurons were made 5 to 7 days after sham-surgery, ovariectomy (OVX), or, in adults, after OVX plus replacement of sub-male androgen levels with dihydrotestosterone implants (OVX + DHT). In 3-week-old mice, OVX did not affect GnRH neuron firing rate in either group. In adult controls, OVX increased GnRH neuron firing rate, which was further enhanced by DHT. In adult PNA mice, however, OVX decreased GnRH neuron firing rate, and DHT restored firing rate to sham-operated levels. In contrast to the differential effects of ovarian feedback on GnRH neuron firing rate, serum LH increased after OVX in both control and PNA mice and was not altered by DHT. Pituitary gene expression largely reflected changes expected with OVX, although in PNA but not control mice, DHT treatment increased Lhb expression. These results suggest prenatal androgen exposure programs marked changes in GnRH neuron regulation by homeostatic steroid feedback. PNA lowers GnRH neuron activity in low-steroid states (before puberty, OVX), and renders activity in adulthood dependent upon ongoing exposure to elevated ovarian androgens.


Assuntos
Androgênios/farmacologia , Hormônio Liberador de Gonadotropina/metabolismo , Neurônios/fisiologia , Ovário/metabolismo , Animais , Di-Hidrotestosterona/farmacologia , Eletrofisiologia , Feminino , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Ovariectomia , Gravidez , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Maturidade Sexual/fisiologia
2.
Proc Natl Acad Sci U S A ; 117(2): 1097-1106, 2020 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-31843923

RESUMO

The molecular mechanisms by which animals integrate external stimuli with internal energy balance to regulate major developmental and reproductive events still remain enigmatic. We investigated this aspect in the marine bristleworm, Platynereis dumerilii, a species where sexual maturation is tightly regulated by both metabolic state and lunar cycle. Our specific focus was on ligands and receptors of the gonadotropin-releasing hormone (GnRH) superfamily. Members of this superfamily are key in triggering sexual maturation in vertebrates but also regulate reproductive processes and energy homeostasis in invertebrates. Here we show that 3 of the 4 gnrh-like (gnrhl) preprohormone genes are expressed in specific and distinct neuronal clusters in the Platynereis brain. Moreover, ligand-receptor interaction analyses reveal a single Platynereis corazonin receptor (CrzR) to be activated by CRZ1/GnRHL1, CRZ2/GnRHL2, and GnRHL3 (previously classified as AKH1), whereas 2 AKH-type hormone receptors (GnRHR1/AKHR1 and GnRHR2/AKHR2) respond only to a single ligand (GnRH2/GnRHL4). Crz1/gnrhl1 exhibits a particularly strong up-regulation in sexually mature animals, after feeding, and in specific lunar phases. Homozygous crz1/gnrhl1 knockout animals exhibit a significant delay in maturation, reduced growth, and attenuated regeneration. Through a combination of proteomics and gene expression analysis, we identify enzymes involved in carbohydrate metabolism as transcriptional targets of CRZ1/GnRHL1 signaling. Our data suggest that Platynereis CRZ1/GnRHL1 coordinates glycoprotein turnover and energy homeostasis with growth and sexual maturation, integrating both metabolic and developmental demands with the worm's monthly cycle.


Assuntos
Hormônio Liberador de Gonadotropina/metabolismo , Homeostase , Proteínas de Insetos/metabolismo , Lua , Neuropeptídeos/metabolismo , Poliquetos/fisiologia , Maturidade Sexual/fisiologia , Transdução de Sinais/fisiologia , Animais , Encéfalo , Proteínas de Ligação a DNA/genética , Técnicas de Silenciamento de Genes , Hormônio Liberador de Gonadotropina/genética , Hormônios de Inseto/genética , Hormônios de Inseto/metabolismo , Proteínas de Insetos/genética , Invertebrados/genética , Neuropeptídeos/genética , Filogenia , Poliquetos/genética , Poliquetos/crescimento & desenvolvimento , Receptores de Neuropeptídeos , Receptores de Peptídeos/genética , Transdução de Sinais/genética , Fatores de Transcrição
3.
PLoS Med ; 16(12): e1002986, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31790400

RESUMO

BACKGROUND: Puberty is a critical period for bone mass accrual, and late puberty in boys is associated with reduced bone mass in adult men. The role of variations in pubertal timing within the normal range for adult fracture risk in men is, however, unknown. We, therefore, assessed the association between age at peak height velocity (PHV), an objective measure of pubertal timing, and fracture risk in adult men. METHODS AND FINDINGS: In the BMI Epidemiology Study Gothenburg, 31,971 Swedish men born between January 1, 1945, and December 31, 1961, with detailed growth data (height and weight) available from centrally archived school healthcare records and the conscription register were followed until December 31, 2016. Age at PHV was calculated according to a modified infancy-childhood-puberty model, and fracture information was retrieved from the Swedish National Patient Register. The mean ± SD age at PHV was 14.1 ± 1.1 years. In total, 5,872 men (18.4%) sustained at least 1 fracture after 20 years of age and 5,731 men (17.9%) sustained a non-vertebral fracture after 20 years of age during a mean ± SD follow-up of 37.3 ± 11.7 years. Cox proportional hazards models adjusted for birth year and country of origin revealed that age at PHV was associated with the risk of any fracture and non-vertebral fracture. Participants with age at PHV in the highest tertile (after 14.5 years of age) were at greater risk of any fracture (hazard ratio [HR] 1.15, 95% confidence interval [CI] 1.08-1.22, P < 0.001) and non-vertebral fracture (HR 1.16, 95% CI 1.09-1.24, P < 0.001) compared with those with age at PHV in the lowest tertile (at 13.6 years of age or younger). Additional adjustments for birthweight, childhood BMI, adult educational level, and young adult height did not attenuate the associations between age at PHV and adult fracture risk. Limitations of this study include the inability to adjust for important risk factors for fracture, inadequate power to assess the relation between pubertal timing and specific fracture types, and the limited generalizability to other populations. CONCLUSIONS: In this study, we observed that late pubertal timing was associated with increased adult fracture risk in men. These findings suggest that information on pubertal timing might aid in the identification of those men at greatest risk of fracture.


Assuntos
Peso Corporal/fisiologia , Fraturas Ósseas/epidemiologia , Maturidade Sexual/fisiologia , Adolescente , Adulto , Estatura/fisiologia , Índice de Massa Corporal , Criança , Estudos de Coortes , Feminino , Humanos , Masculino , Risco , Suécia , Adulto Jovem
4.
Bull Entomol Res ; 109(5): 669-677, 2019 Oct.
Artigo em Romano | MEDLINE | ID: mdl-31379305

RESUMO

The annual bluegrass weevil Listronotus maculicollis requires chilling exposure to terminate reproductive diapause during overwintering, but the effects of temperature on its post-diapause development in spring remain unclear. To explore this effect, overwintering adults were transferred from cold conditions (6°C/4°C, L:D 10:14) to different warm-up temperatures at L:D 12:12. When weevils were transferred to 7, 14 and 21°C in December and late January, the sizes of male and female reproductive organs were significantly smaller at 7°C than at 14 and 21°C. When weevils were transferred to 7, 9, 11, 13 and 15°C in late January, higher temperatures facilitated the post-diapause development. In both sexes, the sizes of reproductive organs and developmental rate increased with temperature. Reproductive organs did not grow significantly at 7°C in males and at 7-9°C in females, at which the percentage of developing weevils remained low. The time required for 50% of individuals to resume development was 44, 18, 13 and 8 days at 9, 11, 13 and 15°C, respectively, in males and 19, 14 and 8 days at 11, 13 and 15°C, respectively, in females. The threshold temperature for post-diapause development was 7.8°C in males, based on which 61.7 degree-days coincided with 50% of individuals developing. Under field conditions, the percentage of male and female maturity and insemination rate were low until early March, but all reached 100% by late March.


Assuntos
Diapausa de Inseto , Temperatura , Gorgulhos/crescimento & desenvolvimento , Animais , Feminino , Genitália Feminina/crescimento & desenvolvimento , Genitália Masculina/crescimento & desenvolvimento , Masculino , Tamanho do Órgão , Maturidade Sexual/fisiologia , Gorgulhos/fisiologia
5.
Artigo em Inglês | MEDLINE | ID: mdl-31398932

RESUMO

Obese children are exposed to short and long-term health consequences, such as dyslipidemia, hypertension and diabetes mellitus. For these reasons, the prevention and treatment of obesity in the pediatric population is a challenge for health care professionals. The aim of this study was to evaluate whether an intensive intervention based on diet and physical activity has a better impact on the auxological and biochemical parameters than standard care (intervention). The study included 20 children (six boys, 14 girls), of the mean age 8.9 (SD 1.4) before puberty. The participants were randomly assigned to two groups: Group I (starting treatment with intensive intervention), and II (starting treatment with standard intervention). After three months, the groups were switched. The comparison of the two interventions in the study group indicates a better effectiveness of intensive intervention in the improvement of anthropometric parameters and majority of biochemical ones (except for insulin concentration, HOMA IR index and LDL cholesterol). As the result of intensive intervention, the mean % of weight-to-height excess and hip circumference decreased significantly (p < 0.005). Our results confirm that complex intervention based on systematic control visits, including personalized dietitian counselling and physician care, during the weight reduction process is more effective than a one-off standard visit.


Assuntos
Terapia Comportamental/métodos , Exercício Físico/fisiologia , Terapia Nutricional/métodos , Obesidade Pediátrica/prevenção & controle , Puberdade/fisiologia , Maturidade Sexual/fisiologia , Perda de Peso/fisiologia , Índice de Massa Corporal , Tamanho Corporal , Criança , Feminino , Humanos , Masculino , Polônia
6.
Anim Reprod Sci ; 208: 106078, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31405470

RESUMO

Enhancing the production of aquatic animals is very important for fishery management and aquaculture applications. Ovaries have important functions in producing oocytes and hormones. The Chinese clam (Mactra chinensis) is a nutritious saltwater shellfish. Significant biochemical changes take place during the sexual maturation of M. chinensis; however, the genetic mechanisms of this process are unclear. Transcriptome sequencing can determine gene expression changes as development occurrs. In the present study, transcriptome sequencing was used to produce a comprehensive transcript dataset for the ovarian development of M. chinensis. The different ovarian developmental stages were determined using hematoxylin-eosin staining. There was identification of 54,172 unigenes at the intermediate stage and 63,081 at the ripening stage, and 80,141 all-unigenes were assembled to determine the molecular mechanism of ovarian development in M. chinensis. Quantitative real-time PCR for nine mRNAs confirmed the RNA-seq data. Functional annotation of the transcripts indicated there were important pathways in ovarian development, such as those involving the vitellogenin gene. Six pathways associated with ovarian development were identified: estrogen signaling pathway, GnRH signaling pathway, progesterone-mediated oocyte maturation, ovarian steroidogenesis, steroid hormone biosynthesis, and steroid biosynthesis. Significant upregulation of protein kinase alpha (PKA) and calmodulin (CAM) in four of the pathways indicates that PKA and CAM are active in M. chinensis ovarian development during maturation. Results of the present study provide the first comprehensive transcriptomic resource for M. chinensis ovaries, which will increase understanding of the molecular mechanisms underlying sexual maturation and promote molecular nutritional studies of M. chinensis.


Assuntos
Bivalves/fisiologia , Regulação da Expressão Gênica/fisiologia , Ovário/fisiologia , Animais , Feminino , Maturidade Sexual/fisiologia
7.
Eur J Endocrinol ; 181(4): R155-R171, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31370006

RESUMO

Introduction: The transition age is the period between childhood to adulthood; it refers to a broad set of physical, cognitive and sociocultural modifications, arbitrarily defined as starting in late puberty and ending with full adult maturation. Pituitary disorders in adolescence represent a challenge that requires careful management during the transition to adult care. Methods: Given the complexity of care of pituitary disorders in the transition age, we have reviewed the relevant medical literature focusing on aetiology, clinical manifestations, treatment strategies of GH deficiency (GHD), hypogonadotrophic hypogonadism (HH) in male and female adolescents, central hypothyroidism (CH), central adrenal insufficiency (CAI) and cranial diabetes insipidus (CDI) at this time. The objective of the present review is to provide an up-to-date evaluation of the transition period to evaluate the specific needs of adolescents with chronic pituitary disease in order to optimise their management. Results: We provide an overview of current clinical management of GHD, HH, CH, CAI and CDI in the transition age. Conclusions: Specific changes occur in pituitary function during the transition period. A holistic approach including discussion of patients' concerns and emotional support should constitute a key component of managing pituitary disorders in adolescence. Special transition clinics where paediatric and adult endocrinologists work together, should be increasingly created and strengthened to bridge care, to promote continuity and adherence to treatment and to limit potential negative development, metabolic, skeletal and cardiovascular sequelae of discontinuity of care among adolescents with pituitary disorders.


Assuntos
Transferência de Pacientes/métodos , Doenças da Hipófise/diagnóstico , Doenças da Hipófise/terapia , Maturidade Sexual/fisiologia , Adolescente , Fatores Etários , Criança , Hormônio do Crescimento Humano/sangue , Humanos , Transferência de Pacientes/tendências , Doenças da Hipófise/sangue , Adulto Jovem
8.
Nat Rev Endocrinol ; 15(10): 615-622, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31406344

RESUMO

Differences of sex development are conditions with discrepancies between chromosomal, gonadal and phenotypic sex. In congenital hypogonadotropic hypogonadism, a lack of gonadotropin activity results primarily in the absence of pubertal development with prenatal sex development being (almost) unaffected in most patients. To expedite progress in the care of people affected by differences of sex development and congenital hypogonadotropic hypogonadism, the European Union has funded a number of scientific networks. Two Actions of the Cooperation of Science and Technology (COST) programmes - DSDnet (BM1303) and GnRH Network (BM1105) - provided the framework for ground-breaking research and allowed the development of position papers on diagnostic procedures and special laboratory analyses as well as clinical management. Both Actions developed educational programmes to increase expertise and promote interest in this area of science and medicine. In this Perspective article, we discuss the success of the COST Actions DSDnet and GnRH Network and the European Reference Network for Rare Endocrine Conditions (Endo-ERN), and provide recommendations for future research.


Assuntos
Transtornos do Desenvolvimento Sexual/epidemiologia , Transtornos do Desenvolvimento Sexual/terapia , Desenvolvimento de Programas/métodos , Desenvolvimento Sexual/fisiologia , Transtornos do Desenvolvimento Sexual/diagnóstico , União Europeia , Feminino , Humanos , Masculino , Puberdade/metabolismo , Maturidade Sexual/fisiologia
9.
J Sports Sci ; 37(22): 2522-2529, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31409199

RESUMO

The aim of the present study was to determine the factors affecting sports involvement in a school-based adolescent population. The cross-sectional cohort study assessed anthropometry, physical capacities and motor competence in 501 boys (aged 10-16 y), from junior (10-12 y) and senior (13-16 y) cohorts. Sports participation data was collected from junior participants. Multivariate analysis of covariance revealed moderate maturity, anthropometry, physical capacity and motor competence differences between sports in the senior cohort (F = 2.616, p < 0.001, η2 = .08), but not in the junior cohort. Furthermore, differences in physical fitness were revealed between playing levels (F = 2.616, p < 0.001, η2 = .08), with a discriminant analysis correctly classifying 73% of participants using aerobic fitness and vertical jump measures. Representative level participants engaged in more structured training and commenced organised competition at a later age (F = 4.332, p < 0.001, η2 = .21). This study's findings are twofold: 1) physical and motor competence profiles differ more between sports with increasing age, and 2) participants at a higher level of competition report delayed engagement in their main sport. As a result, schools may be the ideal environment in which to provide children and adolescents with the opportunity to sample different sports.


Assuntos
Antropometria , Aptidão/fisiologia , Destreza Motora/fisiologia , Aptidão Física , Esportes Juvenis/fisiologia , Adolescente , Fatores Etários , Austrália , Criança , Comportamento Competitivo/fisiologia , Estudos Transversais , Humanos , Masculino , Instituições Acadêmicas , Maturidade Sexual/fisiologia
10.
Dev Cogn Neurosci ; 39: 100690, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31450015

RESUMO

Although there is a long history of studying the influence of pubertal hormones on brain function/structure in animals, this research in human adolescents is young but burgeoning. Here, we provide a comprehensive review of findings from neuroimaging studies investigating the relation between pubertal and functional brain development in humans. We quantified the findings from this literature in which statistics required for standard meta-analyses are often not provided (i.e., effect size in fMRI studies). To do so, we assessed convergence in findings within content domains (reward, facial emotion, social information, cognitive processing) in terms of the locus and directionality (i.e., positive/negative) of effects. Face processing is the only domain with convergence in the locus of effects in the amygdala. Social information processing is the only domain with convergence of positive effects; however, these effects are not consistently present in any brain region. There is no convergence of effects in either the reward or cognitive processing domains. This limited convergence in findings across domains is not the result of null findings or even due to the variety of experimental paradigms researchers employ. Instead, there are critical theoretical, methodological, and analytical issues that must be addressed in order to move the field forward.


Assuntos
Comportamento do Adolescente/fisiologia , Encéfalo/crescimento & desenvolvimento , Emoções/fisiologia , Maturidade Sexual/fisiologia , Adolescente , Comportamento do Adolescente/psicologia , Cognição/fisiologia , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Recompensa
11.
Adv Physiol Educ ; 43(4): 458-466, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31460777

RESUMO

In this teaching laboratory, students design and perform an experiment to determine estrogen's role in imprinting the brain of neonatal rats to express either male or female sexual behavior. A discussion question is provided before the laboratory exercise in which each student is asked to search the literature and provide written answers to questions and to formulate an experiment to test the role of estrogen in imprinting the mating behavior of male and female rats. Students discuss their answers to the questions in laboratory with the instructor and design an experiment to test their hypothesis. In male rats, testosterone is converted by aromatase expressed by neurons in the brain to estrogen. Production of estrogen in the brain of neonatal rats imprints mating behavior in males, where a lack of estrogen action in the brain imprints female sexual behavior. The model involves administering exogenous testosterone to imprint male behavior in female pups or administration of an aromatase inhibitor (letrozole) or an estrogen receptor antagonist (ICI 182,780) to imprint female sexual behavior in male pups. In the model, litters of neonatal pups are treated with either carrier (control), testosterone propionate, aromatase inhibitor (letrozole), or an estrogen receptor antagonist (ICI 182,780) postnatally on days 1 and 3. Alteration of mating behavior is evaluated through the numbers of males and females that breed and establish pregnancy. This is a very simple protocol that provides an excellent experiment for student discussion on the effects of hormone action on imprinting brain sexual behavior.


Assuntos
Encéfalo/fisiologia , Hormônios Esteroides Gonadais/fisiologia , Fisiologia/educação , Comportamento Sexual Animal/fisiologia , Animais , Avaliação Educacional/métodos , Feminino , Humanos , Masculino , Vias Neurais/fisiologia , Ratos , Maturidade Sexual/fisiologia
12.
Rev Saude Publica ; 53: 56, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31432913

RESUMO

OBJECTIVE: To determine whether scores in an adapted version of the self-assessment Pubertal Development Scale into Portuguese match those from the gold standard in pubertal development (Tanner scale). METHODS: This was a cross-sectional study with a convenience sample of 133 children and adolescents aged nine to 17 years (59 males; mean age of 13 years and six months, with standard deviation = 25 months). Youngsters completed the Pubertal Development Scale and were then examined by specialists in adolescent medicine. RESULTS: Exact absolute agreement of pubertal stages were modest, but significant associations between measures (correlation; intra-class correlation coefficients of consistency) showed that the Pubertal Development Scale adequately measures changes that map onto pubertal development determined by physical examination, on par with international publications. Furthermore, scores obtained from each Pubertal Development Scale question reflected adequate gonadal and adrenal events assessed by clinical ratings, mostly with medium/high effect sizes. Latent factors obtained from scores on all Pubertal Development Scale questions had excellent fit indices in Confirmatory Factor Analyses and correlated with Tanner staging. CONCLUSIONS: We conclude that self-assessment of body changes by youngsters using the Portuguese version of the Pubertal Development Scale is useful when estimates of pubertal progression are sufficient, and exact agreement with clinical staging is not necessary. The Pubertal Development Scale is, therefore, a reliable instrument for use in large-scale studies in Brazil that aim at investigating adolescent health related to pubertal developmental. The translated version and scoring systems are provided.


Assuntos
Desenvolvimento do Adolescente/fisiologia , Maturidade Sexual/fisiologia , Inquéritos e Questionários , Tradução , Adolescente , Brasil , Criança , Estudos Transversais , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Autoavaliação
13.
J Dairy Res ; 86(3): 267-271, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31328710

RESUMO

The experiment reported in this research communication aimed to determine the effects of post-weaning feeding level after early weaning on mammary parenchyma development in Alpine goats. Thirty Alpine female goat kids were weaned early (at around 9.8 kg and 32 d of age) and fed different levels of concentrate: Control (C, 730 g DM/d, n = 10), Low (L, 365 g DM/d, n = 10) or High (H, 1090 g DM/d, n = 10) until 235 d of age with ad libitum hay and water. Half of the goat kids were slaughtered before puberty (at around 208 d of age) and half at midgestation (at around 308 d of age and 70 d of gestation) for mammary parenchyma sampling. A histological analysis, Western blot and DNA quantification were performed. Blood samples were taken before puberty and at midgestation to determine plasma levels of IGF-I and prolactin. The mammary gland weights before puberty and at midgestation were positively and significantly associated with concentrate level. However, the organization of the mammary parenchyma and protein expression and quantity of DNA in the parenchyma were similar among the three groups. Before puberty, prolactin and IGF-I concentrations were significantly increased by the feeding level. In conclusion, feeding level after early weaning did not impact mammary parenchyma structure although it modified the weight of the mammary gland. The establishment of the mammary gland was not impacted by rearing management before puberty. Hence, increasing the feeding level during the rearing period could be an interesting way to increase the body development of goats without impairing mammary development whilst having a positive impact on reproductive parameters such as litter weight.


Assuntos
Dieta/veterinária , Cabras/crescimento & desenvolvimento , Glândulas Mamárias Animais/crescimento & desenvolvimento , Maturidade Sexual/fisiologia , Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Animais , DNA/análise , Indústria de Laticínios/métodos , Feminino , Fator de Crescimento Insulin-Like I/análise , Glândulas Mamárias Animais/química , Tamanho do Órgão , Proteínas/análise , Reprodução/fisiologia , Desmame
14.
J Sports Sci ; 37(21): 2492-2498, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31319760

RESUMO

INTRODUCTION: High-Intensity Interval Training (HIIT) and Constant-Intensity Endurance Training (CIET) improves peak oxygen uptake (V̇O2) similarly in adults; but in children this remains unclear, as does the influence of maturity. METHODS: Thirty-seven boys formed three groups: HIIT (football; n = 14; 14.3 ± 3.1 years), CIET (distance runners; n = 12; 13.1 ± 2.5 years) and a control (CON) group (n = 11; 13.7 ± 3.2 years). Peak V̇O2 and gas exchange threshold (GET) were determined from a ramp test and anaerobic performance using a 30 m sprint pre-and-post a three-month training cycle. RESULTS: The HIIT groups peak V̇O2 was significantly higher than the CON group pre (peak V̇O2: 2.54 ± 0.63 l·min-1 vs 2.03 ± 0.53 l·min-1, d = 0.88; GET: 1.41 ± 0.26 l·min-1 vs 1.13 ± 0.29 l·min-1, d = 1.02) and post-training (peak V̇O2: 2.63 ± 0.73 l·min-1 vs 2.08 ± 0.64 l·min-1, d = 0.80; GET: 1.32 ± 0.33 l·min-1 vs 1.15 ± 0.38 l·min-1, d = 0.48). All groups showed a similar magnitude of change during the training (p > 0.05). CONCLUSION: HIIT was not superior to CIET for improving aerobic or anaerobic parameters in adolescents. Secondly, pre- and post-pubertal participants demonstrated similar trainability.


Assuntos
Treino Aeróbico , Treinamento Intervalado de Alta Intensidade , Consumo de Oxigênio/fisiologia , Troca Gasosa Pulmonar/fisiologia , Adolescente , Estatura , Índice de Massa Corporal , Peso Corporal , Criança , Humanos , Masculino , Corrida/fisiologia , Maturidade Sexual/fisiologia , Futebol/fisiologia
15.
PLoS One ; 14(7): e0217986, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31269032

RESUMO

There is limited physiological information on onset of puberty in male lions. The aim of this study was to use longitudinal non-invasive monitoring to: 1) assess changes in steroid metabolite excretory patterns as a function of age and body weight; 2) determine correlations between fecal androgen (FAM) and glucocorticoid (FGM) metabolite concentrations; and 3) confirm spermiogenesis non-invasively through urinalysis. Specifically, FAM and FGM metabolites were analyzed in samples collected twice weekly from 21 male lions at 17 institutions (0.9-16 years of age) for 3.8 months- 2.5 years to assess longitudinal hormone patterns. In addition, body weights were obtained approximately monthly from 10 individuals at five zoos (0.0-3.0 years), and urine was collected from six males at two facilities (1.2-6.3 years) and evaluated for the presence of spermatozoa. An increase in overall mean FAM occurred at 2.0 years of age, at which point concentrations remained similar throughout adulthood. The onset of puberty occurred earlier in captive-born males (<1.2 years of age) compared to wild-born counterparts (<2.5 years of age). Additionally, males in captivity gained an average of 7.3 kg/month compared to 3.9 kg/month for wild males over the first 2-2.5 years of age. Sperm (spermaturia) was observed in males as young as 1.2 years in captivity compared to 2.5 years in the wild (ejaculates). There was no difference in FAM or FGM concentrations with regards to age or season. Overall, this study demonstrates that: 1) captive male lions attain puberty at an earlier age than wild counterparts; 2) onset of puberty is influenced by body weight (growth rate); and 3) spermiogenesis can be confirmed via urinalysis. Knowledge about the linkage between body weight and onset of puberty could facilitate improved reproductive management of ex situ populations via mitigating the risk of unintended breedings in young animals.


Assuntos
Androgênios/metabolismo , Peso Corporal/fisiologia , Glucocorticoides/metabolismo , Leões/fisiologia , Maturidade Sexual/fisiologia , Espermatozoides/metabolismo , Animais , Fezes , Masculino , Espermatozoides/citologia
16.
Exp Oncol ; 41(2): 130-137, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31262156

RESUMO

Stress during puberty and obesity can represent conditions that facilitate the long-term development of diseases, especially for stress-related disorders that depend on neuroendocrine and immune responses. The prostate is prone to diseases that result from neuroendocrine or immune challenges, such as cancer. AIM: In the present study, we assessed the long-term effects of an acute pubertal stressor (immune-challenge) or obesity on the development of precancerous lesions in rats. MATERIALS AND METHODS: Pubertal male rats received a single injection of lipopolysaccharide (LPS) or saline during puberty (5 weeks of age). In adulthood (8 weeks old), subgroups of males were fed with hypercaloric liquid diet to induce obesity. This resulted in a total of six subgroups: (1) intact-non obese, (2) intact-obese, (3) saline-non obese, (4) saline-obese, (5) LPS-non obese, and (6) LPS-obese. At 16 weeks of age the rats were sacrified for prostate histology (hematoxylin and eosin stain) and hormone analysis (testosterone, corticosterone and prolactin). RESULTS: As compared to intact-non obese rats, males treated with LPS and those with obesity expressed histological alterations in both the dorsolateral and ventral portions of the prostate. Only prolactin was altered in LPS-treated males, whereas corticosterone was altered in LPS-obese rats. CONCLUSIONS: These results indicate that puberal exposure to an immune challenge or obesity facilitate the development of prostatic lesions in adult male rats. We discuss the role of hormones in the development of precancerous lesions.


Assuntos
Envelhecimento/fisiologia , Corticosterona/sangue , Obesidade/patologia , Prolactina/sangue , Próstata/patologia , Testosterona/sangue , Animais , Lipopolissacarídeos/toxicidade , Masculino , Lesões Pré-Cancerosas/patologia , Neoplasias da Próstata/patologia , Ratos , Ratos Wistar , Maturidade Sexual/fisiologia
17.
Theriogenology ; 138: 154-163, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31357118

RESUMO

Epigenetic mechanisms are thought to be involved in the reduced developmental capacity of early prepubertal ewe oocytes compared to their adult counterparts. In this study, we have analyzed the global DNA methylation pattern and in vitro meiotic and developmental competence of oocytes at the germinal vesicle (GV) stage obtained from adult and 3-month-old donors. All oocytes were aspirated from antral follicles with a diameter ≥3 mm, and DNA methylation on 5-methylcytosine was detected by immunofluorescence using an anti-methyl cytosine antibody. The main global chromatin configuration pattern shown by both prepubertal and adult ovine oocytes corresponded to condensed chromatin localized close to the nuclear envelope (the SNE pattern). Immunofluorescence showed that a global bright nuclear staining of 5-methylcytosine (5-mC) occurred in all germinal vesicle stage oocytes and matched the propidium iodide staining pattern. The total fluorescence intensity values of lamb GVs were not lower than those observed in adult GVs. The meiotic competence and cleavage rates were similar in adult and prepubertal oocytes, however, the developmental competence of embryos to reach blastocysts was higher for adult oocytes than lamb oocytes (p<0.0001). In conclusion, our results indicate that adult-size oocytes derived from 3 to 4 month old prepubertal ewes show similar GV morphology and DNA methylation staining patterns to those obtained from adult animals, despite exhibiting a lower developmental competence.


Assuntos
Metilação de DNA/fisiologia , Oócitos/citologia , Oócitos/metabolismo , Maturidade Sexual/fisiologia , Ovinos , Fatores Etários , Envelhecimento/genética , Envelhecimento/metabolismo , Animais , Blastocisto/citologia , Blastocisto/metabolismo , Núcleo Celular/metabolismo , Cromatina/metabolismo , Epigênese Genética , Feminino , Técnicas de Maturação in Vitro de Oócitos/veterinária , Meiose/genética , Doação de Oócitos/veterinária , Ovinos/genética
18.
Nutrients ; 11(7)2019 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-31337124

RESUMO

Alterations in pubertal timing have been associated with long-term health outcomes. While a few reports have shown that dietary intake of selenium is associated with fertility and testosterone levels in men, no human studies have considered the association between selenium and pubertal development in children. We examined the cross-sectional association of childhood dietary intake of selenium with pubertal development among 274 girls and 245 boys aged 10-18 years in Mexico City. Multiple logistic and ordinal regression models were used to capture the association between energy-adjusted selenium intake (below Recommended Dietary Allowance (RDA) vs. above RDA) and stages of sexual maturity in children, adjusted for covariates. We found that boys with consumption of selenium below the RDA had lower odds of a higher stage for pubic hair growth (odds ratio (OR) = 0.51, 95% confidence interval (95% CI): 0.27-0.97) and genital development (OR = 0.53, 95% CI: 0.28-0.99) as well as a lower probability of having matured testicular volume (OR = 0.37, 95% CI: 0.15-0.88) compared with boys who had adequate daily dietary intake of selenium (above RDA). No associations were found in girls. According to our results, it is possible that inadequate consumption of selenium may be associated with later pubertal development in boys, suggesting a sex-specific pattern. Future work with a larger sample size and measures of selenium biomarkers is needed to confirm our findings and improve understanding of the role of this mineral in children's sexual development.


Assuntos
Dieta , Puberdade/efeitos dos fármacos , Puberdade/fisiologia , Selênio/administração & dosagem , Maturidade Sexual/efeitos dos fármacos , Adolescente , Criança , Estudos Transversais , Feminino , Humanos , Masculino , México , Recomendações Nutricionais , Selênio/deficiência , Fatores Sexuais , Maturidade Sexual/fisiologia
19.
Theriogenology ; 136: 60-65, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31252323

RESUMO

Sertoli cells nourish developing sperm with the number of Sertoli cells being a major determinant of sperm production capacity in a male. The objectives of these studies were to numerically characterize the prepuberal populations of bovine Sertoli cells to determine the pattern of proliferation and to determine if the prepuberal population could be expanded by reducing endogenous testicular estrogens. Groups of Angus-Hereford crossbred bull calves were castrated at 0.25 mo (n = 6) and 1, 2, 3, 4, 5, or 6 mo of age (n = 8 per age). Testes were weighed and equatorial slices fixed. Sertoli cell density was determined following labeling of Sertoli cells with GATA-4 antibody in 30-µm thick sections. The number of Sertoli cells per testis increased linearly from 0.25 mo to 5 mo of age. Sertoli cell numbers appeared to plateau at 5 mo of age with luminal development present at that age. Only a single postnatal wave of Sertoli cell proliferation was detectable in the bull. To evaluate the regulatory role of testicular estrogens, Jersey bull caves were treated twice weekly with the aromatase inhibitor, letrozole, from 2 to 22 wk of age and control animals were treated with the canola oil vehicle. Testes were retrieved at 26 wk of age. Testes were weighed and Sertoli cell density was subsequently determined. Estradiol was lower in testicular tissue from letrozole-treated bulls as expected (P < 0.001). Inhibition of aromatase had no effect on testosterone or circulating LH; testosterone increased with age as expected. Inhibition of aromatase and consequent reduced testicular estradiol did not alter Sertoli cell numbers.


Assuntos
Proliferação de Células/efeitos dos fármacos , Estradiol/metabolismo , Letrozol/farmacologia , Células de Sertoli/fisiologia , Maturidade Sexual/fisiologia , Testículo/efeitos dos fármacos , Envelhecimento , Animais , Inibidores da Aromatase/administração & dosagem , Inibidores da Aromatase/farmacologia , Bovinos , Letrozol/administração & dosagem , Masculino , Testículo/fisiologia
20.
Eur J Endocrinol ; 181(2): 129-137, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31146258

RESUMO

Objective: Previous finding suggests that children growing up under chronic stress tend to experience earlier sexual maturity. The present study aims to examine polygenic risk by experience interaction in predicting pubertal timing, as well as provide insight regarding the relevance of two G × E paradigms. Design and methods: Data were analyzed from a 3-year prospective puberty cohort in Anhui Province, China. Breast Tanner stage and testicular volume (TV) of 997 children were annually assessed. The polygenic risk score (PRS) was computed based on 17 SNPs for early pubertal timing. Hair cortisol concentrations (HCC) were assessed in the first 3 cm hair segment as a biological marker of chronic stress. Results: Comparing with participants under moderate levels of stress as measured by HCC, the puberty-accelerating effects of chronic stress were only observed among girls with moderate (1.7 months earlier, P = 0.007) and low genetic susceptibility (2.2 months earlier, P < 0.001) and among boys with high genetic susceptibility (2.0 months earlier, P = 0.005). Polygenic differences (PRSs) in age at thelarche was most prominent in those with low levels of stress by HCC (9.06, 9.36 and 9.53 years for high, moderate and low PRS, respectively; F = 105.06, P < 0.0001), while polygenic differences in age at TV ≥4 mL was strongest in those under chronic stress (10.91, 11.06 and 11.17 years for high, moderate and low PRS, respectively; F = 100.48, P < 0.0001). Conclusion: Chronic stress predicts earlier age at pubertal onset in a sex-specific and genetic background-dependent manner. The bioecological G × E model for girls and diathesis stress model for boys in pubertal timing warrants further investigation.


Assuntos
Interação Gene-Ambiente , Herança Multifatorial/genética , Puberdade Precoce/genética , Puberdade Precoce/psicologia , Estresse Psicológico/genética , Estresse Psicológico/psicologia , Criança , China/epidemiologia , Doença Crônica , Estudos de Coortes , Feminino , Humanos , Estudos Longitudinais , Masculino , Estudos Prospectivos , Puberdade/fisiologia , Puberdade/psicologia , Puberdade Precoce/epidemiologia , Fatores de Risco , Maturidade Sexual/fisiologia , Estresse Psicológico/epidemiologia
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