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1.
Elife ; 122023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-38126277

RESUMO

Evidence suggests that estradiol-sensing preoptic area GABA neurons are involved in the preovulatory surge mechanism necessary for ovulation. In vivo CRISPR-Cas9 editing was used to achieve a 60-70% knockdown in estrogen receptor alpha (ESR1) expression by GABA neurons located within the regions of the rostral periventricular area of the third ventricle (RP3V) and medial preoptic nuclei (MPN) in adult female mice. Mice exhibited variable reproductive phenotypes with the only significant finding being mice with bilateral ESR1 deletion in RP3V GABA neurons having reduced cFos expression in gonadotropin-releasing hormone (GnRH) neurons at the time of the surge. One sub-population of RP3V GABA neurons expresses kisspeptin. Re-grouping ESR1-edited mice on the basis of their RP3V kisspeptin expression revealed a highly consistent phenotype; mice with a near-complete loss of kisspeptin immunoreactivity displayed constant estrus and failed to exhibit surge activation but retained pulsatile luteinizing hormone (LH) secretion. These observations demonstrate that ESR1-expressing GABA-kisspeptin neurons in the RP3V are essential for the murine preovulatory LH surge mechanism.


Assuntos
Sistemas CRISPR-Cas , Kisspeptinas , Camundongos , Feminino , Animais , Kisspeptinas/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Neurônios GABAérgicos/metabolismo , Ciclo Estral/fisiologia , Ácido gama-Aminobutírico/metabolismo
2.
Nat Commun ; 13(1): 7433, 2022 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-36460649

RESUMO

The mechanisms underlying the homeostatic estrogen negative feedback pathway central to mammalian fertility have remained unresolved. Direct measurement of gonadotropin-releasing hormone (GnRH) pulse generator activity in freely behaving mice with GCaMP photometry demonstrated striking estradiol-dependent plasticity in the frequency, duration, amplitude, and profile of pulse generator synchronization events. Mice with Cre-dependent deletion of ESR1 from all kisspeptin neurons exhibited pulse generator activity identical to that of ovariectomized wild-type mice. An in vivo CRISPR-Cas9 approach was used to knockdown ESR1 expression selectively in arcuate nucleus (ARN) kisspeptin neurons. Mice with >80% deletion of ESR1 in ARN kisspeptin neurons exhibited the ovariectomized pattern of GnRH pulse generator activity and high frequency LH pulses but with very low amplitude due to reduced responsiveness of the pituitary. Together, these studies demonstrate that estrogen utilizes ESR1 in ARN kisspeptin neurons to achieve estrogen negative feedback of the GnRH pulse generator in mice.


Assuntos
Hormônio Liberador de Gonadotropina , Kisspeptinas , Feminino , Camundongos , Animais , Kisspeptinas/genética , Retroalimentação , Estrogênios , Núcleo Arqueado do Hipotálamo , Mamíferos
3.
Int J Mol Sci ; 23(14)2022 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-35887264

RESUMO

Vascular smooth muscle cells (VSMCs) help to maintain the normal physiological contractility of arterial vessels to control blood pressure; they can also contribute to vascular disease such as atherosclerosis. Ca2+/calmodulin-dependent kinase II (CaMKII), a multifunctional enzyme with four isoforms and multiple alternative splice variants, contributes to numerous functions within VSMCs. The role of these isoforms has been widely studied across numerous tissue types; however, their functions are still largely unknown within the vasculature. Even more understudied is the role of the different splice variants of each isoform in such signaling pathways. This review evaluates the role of the different CaMKII splice variants in vascular pathological and physiological mechanisms, aiming to show the need for more research to highlight both the deleterious and protective functions of the various splice variants.


Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina , Músculo Liso Vascular , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Transdução de Sinais/fisiologia
4.
Artigo em Inglês | MEDLINE | ID: mdl-35897465

RESUMO

There is increasing debate as to whether transwoman athletes should be included in the elite female competition. Most elite sports are divided into male and female divisions because of the greater athletic performance displayed by males. Without the sex division, females would have little chance of winning because males are faster, stronger, and have greater endurance capacity. Male physiology underpins their better athletic performance including increased muscle mass and strength, stronger bones, different skeletal structure, better adapted cardiorespiratory systems, and early developmental effects on brain networks that wires males to be inherently more competitive and aggressive. Testosterone secreted before birth, postnatally, and then after puberty is the major factor that drives these physiological sex differences, and as adults, testosterone levels are ten to fifteen times higher in males than females. The non-overlapping ranges of testosterone between the sexes has led sports regulators, such as the International Olympic Committee, to use 10 nmol/L testosterone as a sole physiological parameter to divide the male and female sporting divisions. Using testosterone levels as a basis for separating female and male elite athletes is arguably flawed. Male physiology cannot be reformatted by estrogen therapy in transwoman athletes because testosterone has driven permanent effects through early life exposure. This descriptive critical review discusses the inherent male physiological advantages that lead to superior athletic performance and then addresses how estrogen therapy fails to create a female-like physiology in the male. Ultimately, the former male physiology of transwoman athletes provides them with a physiological advantage over the cis-female athlete.


Assuntos
Atletas , Desempenho Atlético , Adulto , Desempenho Atlético/fisiologia , Estrogênios , Feminino , Humanos , Masculino , Caracteres Sexuais , Testosterona
5.
J Steroid Biochem Mol Biol ; 218: 106049, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34990809

RESUMO

Recent studies have highlighted the potential role of 11oxygenated (keto or hydroxy) androgens in human reproductive function with 11keto androgens circulating at concentrations comparable with testosterone in women and children. However, the intrinsic androgenic bioactivities of 11 keto and hydroxy androgens are not fully characterized. We therefore investigated the full androgen dose-response curves using complementary in vitro yeast and mammalian (HEK293) host cell bioassays of 11 keto and hydroxy derivatives of the potent androgens, testosterone (T) and dihydrotestosterone (DHT), compared with their parent non-11 oxygenated steroids together with the pro-androgen precursor (androstenedione (A4)) and metabolites (androstanedione, androsterone). For potent androgens, the mammalian HEK293 host cell bioassay was 22-138 times more sensitive than the yeast host cell bioassay. In both androgen bioassays, 11keto derivatives displayed androgenic bioactivity but significantly lower molar potency than their parent non-keto steroids. By contrast, the 11hydroxy derivatives had minimal or no androgenic bioactivity. In both bioassays 5α-reduction increased androgenic potency. These findings confirm that that 11keto androgens may contribute directly to androgen status in women, children, and other conditions apart from healthy eugonadal men whereas 11hydroxy androgens have negligible androgenic potency although it cannot be excluded that they may be converted to more potent androgens in vivo.


Assuntos
Androgênios , Saccharomyces cerevisiae , Androgênios/metabolismo , Androstenodiona/metabolismo , Animais , Criança , Di-Hidrotestosterona/metabolismo , Di-Hidrotestosterona/farmacologia , Feminino , Células HEK293 , Humanos , Masculino , Mamíferos/metabolismo , Saccharomyces cerevisiae/metabolismo , Esteroides/metabolismo , Testosterona/metabolismo
7.
Drug Test Anal ; 13(5): 894-902, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33864649

RESUMO

Androgens, both steroidal and nonsteroidal in nature, are among the most commonly misused substances in competitive sports. Their recognized anabolic and performance enhancing effects through short- and long-term physiological adaptations make them popular. Androgens exist as natural steroids, or are chemically synthesized as anabolic androgenic steroids (AAS) or selective androgen receptor modulators (SARMs). In order to effectively detect misuse of androgens, targeted strategies are used. These targeted strategies rely heavily on mass spectrometry, and detection requires prior knowledge of the targeted structure and its metabolites. Although exquisitely sensitive, such approaches may fail to detect novel structures that are developed and marketed. A nontargeted approach to androgen detection involves the use of cell-based in vitro bioassays. Both yeast and mammalian cell androgen bioassays demonstrate a clear ability to detect AAS and SARMS, and if paired with high resolution mass spectrometry can putatively identify novel structures. In vitro cell bioassays are successfully used to characterize designer molecules and to detect exogenous androgens in biological samples. It is important to continue to develop new and effective detection approaches to prevent misuse of designer androgens, and in vitro bioassays represent a potential solution to nontargeted detection strategies.


Assuntos
Anabolizantes/análise , Androgênios/análise , Bioensaio , Drogas Desenhadas/análise , Dopagem Esportivo , Substâncias para Melhoria do Desempenho/análise , Detecção do Abuso de Substâncias , Linhagem Celular , Humanos , Valor Preditivo dos Testes , Receptores Androgênicos/efeitos dos fármacos , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo , Reprodutibilidade dos Testes , Elementos de Resposta , Leveduras/efeitos dos fármacos , Leveduras/genética , Leveduras/metabolismo
8.
Front Sports Act Living ; 3: 601420, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33681758

RESUMO

Health is a pre-requisite for optimal performance yet the parameters which govern health and performance of elite female athletes are little understood. The aim of this study was to quantify the health status of elite female athletes, and understand sociocultural factors influencing that status. The survey addressed demographic, health and athletic performance history, training load, contraceptive use, sport-specific appearance and performance pressures, and communication barriers. Three hundred and fifty-seven elite New Zealand female athletes were recruited to complete an on-line survey. Two hundred and nineteen athletes completed the survey. Oligomenorrhea/amenorrhea had been diagnosed in only 12% of athletes compared with 50% of athletes not on hormonal contraception who reported symptoms consistent with this diagnosis. Stress fractures and iron deficiency were common and associated with oligomenorrhoea/amenorrhea (P = 0.002), disordered eating (P = 0.009) or menorrhagia (P = 0.026). Athletes involved in individual sports (P = 0.047) and with higher training volumes (P < 0.001) were more likely to report a medical illness. Seventy-three percent of athletes felt pressured by their sport to alter their physical appearance to conform to gender ideals with 15% engaging in disordered eating practices. Barriers to communicating female health issues included male coaches and support staff, and lack of quality information pertaining to health. Elite female athletes may fail to reach peak performance due to specific health issues and undiagnosed pathology. Sociocultural factors influence the effectiveness of support of female's health and performance. Organizational and cultural change is required if elite female athletes are to combine optimal health with best performance.

9.
Drug Test Anal ; 13(5): 903-915, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33709622

RESUMO

Androgens remain abused performance-enhancing drugs in sports. Technologies based on mass spectrometry can detect all forms of androgens but fail if the androgen represents a novel structure. A bioassay detects androgens based on function rather than structure. To date, there has been limited adoption of cell-based in vitro bioassays as a screening tool for nontargeted androgen detection because they require expert personnel and specialized equipment to perform. We now describe the development of a cell-free version of an androgen in vitro bioassay. Stage 1 involved in vitro transcription/translation reactions (IVTT) using a DNA template encoding an enhancer/androgen response element (ARE) regulatory region upstream of a minimal promoter that drives expression of a reporter protein. The assay detected testosterone across the concentration range of 106.7 to 0.0144 ng/ml (3.7 × 10-7 to 5 × 10-11 M), with an EC50 of 6.63 ng/ml (23 nM). To reduce complexity, Stages 2-4 of development included just in vitro transcription (IVT) reactions, whereby the output was an RNA molecule. Stage 2 involved directly labelling the RNA molecule with fluorophore-labelled nucleotide triphosphates, Stage 3 involved reverse transcription-polymerase chain reaction (PCR) of the RNA molecule, and Stage 4 utilized an RNA aptamer, Mango II, as its RNA output. The Stage 4 product detected testosterone across the range of 106.7-0.0001 ng/ml (3.7 × 10-7 to 5 × 10-13 M), with an EC50 of 0.04 ng/ml (0.155 nM). Further to this, we show that the Stage 4 product can detect other androgenic molecules. Relative to cell-based bioassays, the Stage 4 product is easy to perform and could be developed into a routine, high-throughput, nontargeted androgen screen.


Assuntos
Anabolizantes/análise , Androgênios/análise , Bioensaio , Dopagem Esportivo , Substâncias para Melhoria do Desempenho/análise , Receptores Androgênicos/efeitos dos fármacos , Detecção do Abuso de Substâncias , Sistema Livre de Células , Genes Reporter , Proteínas de Fluorescência Verde/biossíntese , Proteínas de Fluorescência Verde/genética , Células HEK293 , Células HeLa , Ensaios de Triagem em Larga Escala , Humanos , Valor Preditivo dos Testes , Estudo de Prova de Conceito , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo , Reprodutibilidade dos Testes , Elementos de Resposta , Transcrição Gênica
10.
Drug Test Anal ; 13(3): 523-528, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33037724

RESUMO

Altrenogest is a commonly used progestogen for the suppression of oestrus and associated distracting behaviours that interfere with training and performance of female racehorses. The steroid is derived from 19-nor testosterone and is structurally similar to the anabolic androgenic steroid, trenbolone. In this study, the relative androgen potency of altrenogest was determined by a kidney (HEK293) cell androgen bioassay. The HEK293 bioassay shows that in its pure form, altrenogest has a high relative potency compared with testosterone but is not as strong as ß-trenbolone. Our results also show that altrenogest is able to activate the androgen receptor at the concentrations relevant to the administration regime of racehorses and retains its activity ex vivo. Thus, we show unequivocally that altrenogest, a progestogen used widely in female racehorses, acts as a strong androgen in a mammalian cell bioassay.


Assuntos
Androgênios/farmacologia , Progestinas/farmacologia , Acetato de Trembolona/análogos & derivados , Animais , Dopagem Esportivo , Feminino , Células HEK293 , Cavalos , Humanos , Masculino , Acetato de Trembolona/farmacologia
11.
Int J Mol Sci ; 21(13)2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32630298

RESUMO

Differences in size or composition of existing plaques at the initiation of estrogen (E2) therapy may underpin evidence of increased risk of atherosclerosis-associated clinical sequelae. We investigated whether E2 had divergent effects on actively-growing versus established-advanced atherosclerotic lesions. Eight weeks of subcutaneous bi-weekly injections of 3 µg/g 17ß-estradiol (n = 18) or vehicle control (n = 22) were administered to female Apolipoprotein null-mice aged 25- or 45 weeks old. Histological assessment of lesion size within the brachiocephalic artery was conducted. Lesion composition was also assessed with acellular, calcification and fibrosis areas measured and other cellular features (intimal thickening, foam cells, lipid pools and cholesterol) scored (0-3) for severity. The comparison showed increased lesion size and calcified area with advancing age but no effect of E2. However, subtle changes in composition were observed following E2. Within the younger group, E2 increased intima thickening and acceleration of calcification. In the older group, E2 increased the thickness of the lesion cap. Therefore, this study shows different effects of E2 depending on the underlying stage of lesion development at the time of initiation of treatment. These divergent changes help explain the controversy of the adverse effects of E2 treatment in cardiovascular disease.


Assuntos
Aterosclerose/tratamento farmacológico , Aterosclerose/patologia , Estradiol/farmacologia , Animais , Aorta/patologia , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Aterosclerose/metabolismo , Colesterol/fisiologia , Modelos Animais de Doenças , Estradiol/metabolismo , Estrogênios/metabolismo , Estrogênios/farmacologia , Feminino , Fibrose , Lipídeos/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fatores de Tempo , Calcificação Vascular
12.
Drug Test Anal ; 12(6): 752-762, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31950580

RESUMO

Hemapolin (2α,3α-epithio-17α-methyl-5α-androstan-17ß-ol) is a designer steroid that is an ingredient in several "dietary" and "nutritional" supplements available online. As an unusual chemical modification to the steroid A-ring could allow this compound to pass through antidoping screens undetected, the metabolism of hemapolin was investigated by an in vivo equine drug administration study coupled with GC-MS analysis. Following administration of synthetically prepared hemapolin to a thoroughbred horse, madol (17α-methyl-5α-androst-2-en-17ß-ol), reduced and dihydroxylated madol (17α-methyl-5α-androstane-2ß,3α,17ß-triol), and the isomeric enone metabolites 17ß-hydroxy-17α-methyl-5α-androst-3-en-2-one and 17ß-hydroxy-17α-methyl-5α-androst-2-en-4-one, were detected and confirmed in equine urine extracts by comparison with a library of synthetically derived reference materials. A number of additional madol derivatives derived from hydroxylation, dihydroxylation, and trihydroxylation were also detected but not fully identified by this approach. A yeast cell-based androgen receptor bioassay of available reference materials showed that hemapolin and many of the metabolites identified by this study were potent activators of the equine androgen receptor. This study reveals the metabolites resulting from the equine administration of the androgen hemapolin that can be incorporated into routine GC-MS antidoping screening and confirmation protocols to detect the illicit use of this agent in equine sports.


Assuntos
Drogas Desenhadas/metabolismo , Dopagem Esportivo/métodos , Cavalos/metabolismo , Esteroides/metabolismo , Detecção do Abuso de Substâncias/métodos , Congêneres da Testosterona/metabolismo , Animais , Biotransformação , Cromatografia Gasosa-Espectrometria de Massas , Receptores Androgênicos/metabolismo , Padrões de Referência , Esteroides/urina , Congêneres da Testosterona/urina
13.
PLoS One ; 15(1): e0226931, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31914125

RESUMO

BACKGROUND: Apolipoprotein-AI (apo-AI) is the major apolipoprotein found in high density lipoprotein particles (HDLs). We previously demonstrated that apo-AI injected directly into high-fat diet fed mice improved insulin sensitivity associated with decreased hepatic inflammation. While our data provides compelling proof of concept, apoA-I mimetic peptides are more clinically feasible. The aim of this study was to test whether apo-AI mimetic peptide (D-4F and L-5F) treatment will emulate the effects of full-length apo-AI to improve insulin sensitivity. METHODS: Male C57BL/6 mice were fed a high-fat diet for 16 weeks before receiving D4F mimetic peptide administered via drinking water or L5F mimetic peptide administered by intraperitoneal injection bi-weekly for a total of five weeks. Glucose tolerance and insulin tolerance tests were conducted to assess the effects of the peptides on insulin resistance. Effects of the peptides on inflammation, gluconeogenic enzymes and lipid synthesis were assessed by real-time PCR of key markers involved in the respective pathways. RESULTS: Treatment with apo-AI mimetic peptides D-4F and L-5F showed: (i) improved blood glucose clearance (D-4F 1.40-fold AUC decrease compared to HFD, P<0.05; L-4F 1.17-fold AUC decrease compared to HFD, ns) in the glucose tolerance test; (ii) improved insulin tolerance (D-4F 1.63-fold AUC decrease compared to HFD, P<0.05; L-5F 1.39-fold AUC compared to HFD, P<0.05) in the insulin tolerance test. The metabolic test results were associated with (i) decreased hepatic inflammation of SAA1, IL-1ß IFN-γ and TNFα (2.61-5.97-fold decrease compared to HFD, P<0.05) for both mimetics; (ii) suppression of hepatic mRNA expression of gluconeogenesis-associated genes (PEPCK and G6Pase; 1.66-3.01-fold decrease compared to HFD, P<0.001) for both mimetics; (iii) lipogenic-associated genes, (SREBP1c and ChREBP; 2.15-3.31-fold decrease compared to HFD, P<0.001) for both mimetics and; (iv) reduced hepatic macrophage infiltration (F4/80 and CD68; 1.77-2.15-fold compared to HFD, P<0.001) for both mimetics. CONCLUSION: Apo-AI mimetic peptides treatment led to improved glucose homeostasis. This effect is associated with reduced expression of inflammatory markers in the liver and reduced infiltration of macrophages, suggesting an overall suppression of hepatic inflammation. We also showed altered expression of genes associated with gluconeogenesis and lipid synthesis, suggesting that glucose and lipid synthesis is suppressed. These findings suggest that apoA-I mimetic peptides could be a new therapeutic option to reduce hepatic inflammation that contributes to the development of overnutrition-induced insulin resistance.


Assuntos
Apolipoproteína A-I/uso terapêutico , Inflamação/tratamento farmacológico , Resistência à Insulina , Peptídeos e Proteínas de Sinalização Intercelular/uso terapêutico , Fígado/efeitos dos fármacos , Animais , Glicemia/análise , Inflamação/patologia , Fígado/patologia , Masculino , Camundongos Endogâmicos C57BL
14.
J Med Ethics ; 45(6): 395-403, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31217230

RESUMO

The inclusion of elite transwomen athletes in sport is controversial. The recent International Olympic Committee (IOC) (2015) guidelines allow transwomen to compete in the women's division if (amongst other things) their testosterone is held below 10 nmol/L. This is significantly higher than that of cis-women. Science demonstrates that high testosterone and other male physiology provides a performance advantage in sport suggesting that transwomen retain some of that advantage. To determine whether the advantage is unfair necessitates an ethical analysis of the principles of inclusion and fairness. Particularly important is whether the advantage held by transwomen is a tolerable or intolerable unfairness. We conclude that the advantage to transwomen afforded by the IOC guidelines is an intolerable unfairness. This does not mean transwomen should be excluded from elite sport but that the existing male/female categories in sport should be abandoned in favour of a more nuanced approach satisfying both inclusion and fairness.


Assuntos
Esportes/ética , Pessoas Transgênero , Atletas , Desempenho Atlético/ética , Feminino , Humanos , Masculino , Esportes/normas , Testosterona/sangue
15.
Emerg Top Life Sci ; 3(6): 759-762, 2019 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-32915214

RESUMO

We support gender equality and freedoms in cases in which 'like equals like'. Such inclusion is central to a progressive society. However, inclusion could potentially conflict with fairness in cases concerning transgendered athletes in elite sport. Accepted science regarding male and female physiology suggests that transwomen have an advantage over their cisgendered counterparts. This advantage stems from relatively high testosterone levels and prior male physiology of transwomen. Conversely, transmen who wish to compete in the men's division may be disadvantaged in comparison with cismen. Hence, while inclusion supports transwomen and transmen competing in the division that matches their gender identity, this may not satisfy the principle of fairness. We reason that transwomen and cismen are not only advantaged, but unfairly advantaged, and propose that the gender binary in elite sport should be replaced with a nuanced algorithm that accounts for both physiological and social parameters. As the algorithm would be applied to all athletes, it would be both inclusive and fair.


Assuntos
Esportes/legislação & jurisprudência , Transexualidade/classificação , Atletas , Feminino , Identidade de Gênero , Humanos , Masculino , Desenvolvimento Muscular , Músculos/metabolismo , Análise para Determinação do Sexo , Testosterona/metabolismo , Pessoas Transgênero
17.
Exp Physiol ; 103(10): 1309-1317, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30051938

RESUMO

NEW FINDINGS: What is the topic of this review? We review methodological considerations for the inclusion of women in sex and menstrual cycle phase comparison studies. What advances does it highlight? Improving the methodological design for studies exploring sex differences, menstrual cycle phase differences and/or endogenous versus exogenous female sex hormones will help to close the gap in our understanding of the effects of endogenous and exogenous hormones on exercise science and sports medicine outcomes. ABSTRACT: In recent years, the increase in scientific literature exploring sex differences has been beneficial to both clinicians and allied health science professionals, although female athletes are still significantly under-represented in sport and exercise science research. Women have faced exclusion throughout history though the complexities of sociocultural marginalization and biomedical disinterest in women's health. These complexities have contributed to challenges of studying women and examining sex differences. One underlying complexity to methodological design may be hormonal perturbations of the menstrual cycle. The biphasic responses of oestrogen and progesterone across the menstrual cycle significantly influence physiological responses, which contribute to exercise capacity and adaptation in women. Moreover, oral contraceptives add complexity through the introduction of varying concentrations of circulating exogenous oestrogen and progesterone, which may moderate physiological adaptations to exercise in a different manner to endogenous ovarian hormones. Thus, applied sport and exercise science research focusing on women remains limited, in part, by poor methodological design that does not define reproductive status. By highlighting specific differences between phases with regard to hormone perturbations and the systems that are affected, methodological inconsistencies can be reduced, thereby improving scientific design that will enable focused research on female athletes in sports science and evaluation of sex differences in responses to exercise. The aims of this review are to highlight the differences between endogenous and exogenous hormone profiles across a standard 28-32 day menstrual cycle, with the goal to improve methodological design for studies exploring sex differences, menstrual cycle phase differences and/or endogenous versus exogenous female sex hormones.


Assuntos
Ciclo Menstrual/fisiologia , Adaptação Fisiológica/fisiologia , Atletas , Anticoncepcionais Orais/farmacologia , Estrogênios/metabolismo , Exercício Físico/fisiologia , Feminino , Humanos , Ciclo Menstrual/efeitos dos fármacos , Ciclo Menstrual/metabolismo , Progesterona/metabolismo , Caracteres Sexuais , Esportes/fisiologia
18.
Heart Lung Circ ; 27(5): 560-567, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29409723

RESUMO

Signalling mechanisms within and between cells of the vasculature enable function and maintain homeostasis. However, a number of these mechanisms also contribute to the pathophysiology of vascular disease states. The multifunctional signalling molecule calcium/calmodulin-dependent kinase II (CaMKII) has been shown to have critical functional effects in many tissue types. For example, CaMKII is known to have a dual role in cardiac physiology and pathology. The function of CaMKII within the vasculature is incompletely understood, but emerging evidence points to potential physiological and pathological roles. This review discusses the evidence for CaMKII signalling within the vasculature, with the aim to better understand both positive and potentially deleterious effects of CaMKII activation in vascular tissue.


Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Endotélio Vascular/metabolismo , Doenças Vasculares/enzimologia , Animais , Sinalização do Cálcio , Humanos
19.
Int J Sport Nutr Exerc Metab ; 28(1): 10-18, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-28787178

RESUMO

Both athletes and the general population use nutritional supplements. Athletes often turn to supplements hoping that consuming the supplement will help them be more competitive and healthy, while the general population hopes to improve body image or vitality. While many supplements contain ingredients that may have useful properties, there are supplements that are contaminated with compounds that are banned for use in sport or have been deliberately adulterated to fortify a supplement with an ingredient that will produce the advertised effect. In the present study, we have used yeast cell and mammalian cell androgen bioassays to characterize the androgenic bioactivity of 112 sports supplements available from the Australian market, either over the counter or via the Internet. All 112 products did not declare an androgen on the label as an included ingredient. Our findings show that six out of 112 supplements had strong androgenic bioactivity in the yeast cell bioassay, indicating products spiked or contaminated with androgens. The mammalian cell bioassay confirmed the strong androgenic bioactivity of five out of six positive supplements. Supplement 6 was metabolized to weaker androgenic bioactivity in the mammalian cells. Further to this, Supplement 6 was positive in a yeast cell progestin bioassay. Together, these findings highlight that nutritional supplements, taken without medical supervision, could expose or predispose users to the adverse consequences of androgen abuse. The findings reinforce the need to increase awareness of the dangers of nutritional supplements and highlight the challenges that clinicians face in the fast-growing market of nutritional supplements.


Assuntos
Androgênios/análise , Suplementos Nutricionais , Análise de Alimentos/métodos , Bioensaio , Linhagem Celular , Dopagem Esportivo , Humanos , Progestinas , Leveduras/efeitos dos fármacos
20.
Oxid Med Cell Longev ; 2017: 7020295, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28690764

RESUMO

Facioscapulohumeral muscular dystrophy (FSHD) is an inherited myopathy affecting approximately 1 in 7500 individuals worldwide. It is a progressive disease characterised by skeletal muscle weakness and wasting. A genetic mutation on the 4q35 chromosome results in the expression of the double homeobox 4 gene (DUX4) which drives oxidative stress, inflammation, toxicity, and atrophy within the skeletal muscle. FSHD is characterised by oxidative stress, and there is currently no cure and a lack of therapies for the disease. Antioxidants have been researched for many years, with investigators aiming to use antioxidants therapeutically for oxidative stress-associated diseases. This has included both natural and synthetic antioxidants. The use of antioxidants in preclinical or clinical models has been largely successful with a plethora of research reporting positive results. However, when translated to clinical trials, the use of antioxidants as a therapeutic intervention for a variety of disease has been largely unsuccessful. Moreover, specifically focusing on FSHD, limited research has been conducted on the use of antioxidants as a therapy in either preclinical or clinical models. This review summarises the current state of antioxidant use in the treatment of FSHD and discusses their potential avenue for therapeutic use for FSHD patients.


Assuntos
Antioxidantes/uso terapêutico , Distrofia Muscular Facioescapuloumeral/tratamento farmacológico , Humanos , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Distrofia Muscular Facioescapuloumeral/metabolismo , Estresse Oxidativo/efeitos dos fármacos
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