Página 1 dos resultados de 6009 itens digitais encontrados em 1.612 segundos

‣ Testosterone suppresses oxidative stress in human neutrophils

MARIN, Douglas Popp; BOLIN, Anaysa Paola; SANTOS, Rita de Cassia Macedo dos; Curi, Rui; OTTON, Rosemari
Fonte: JOHN WILEY & SONS LTD Publicador: JOHN WILEY & SONS LTD
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
37.087468%
The in vitro effect of testosterone on human neutrophil function was investigated. Blood neutrophils from healthy male subjects were isolated and treated with 10 nM, 0.1 and 10 mu M testosterone for 24 h. As compared with untreated cells, the testosterone treatment produced a significant decrease of superoxide production as indicated by the measurement of extra- and intracellular superoxide content. An increment in the production of nitric oxide was observed at 0.1 and 10 mu M testosterone concentrations, whereas no effect was found for 10 nM. Intracellular calcium mobilization was significantly increased at 10 nM, whereas it was reduced at 10 mu M testosterone. There was an increase in phagocytic capacity at 10 nM and a decrease of microbicidal activity in neutrophils treated with testosterone at 10 mu M. Glutathione reductase activity was increased by testosterone treatment, whereas no effect was observed in other antioxidant enzyme activities. An increase in the content of thiol groups was observed at all testosterone concentrations. Lipid peroxidation in neutrophils evaluated by levels of TBARS was decreased at 10 nM and 0.1 mu M testosterone. These results indicate the antioxidant properties of testosterone in neutrophils as suggested by reduction of superoxide anion production...

‣ Testosterone Induces Vascular Smooth Muscle Cell Migration by NADPH Oxidase and c-Src-Dependent Pathways

Chignalia, Andreia Z.; Schuldt, Elke Z.; Camargo, Lívia de Lucca; Montezano, Augusto C.; Callera, Gláucia Elena; Laurindo, Francisco Rafael Martins; Lopes, Lucia Rossetti; Avellar, Maria Christina Werneck de; Carvalho, Maria Helena Catelli de; Fortes, Z
Fonte: LIPPINCOTT WILLIAMS & WILKINS; PHILADELPHIA Publicador: LIPPINCOTT WILLIAMS & WILKINS; PHILADELPHIA
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
37.074868%
Testosterone has been implicated in vascular remodeling associated with hypertension. Molecular mechanisms underlying this are elusive, but oxidative stress may be important. We hypothesized that testosterone stimulates generation of reactive oxygen species (ROS) and migration of vascular smooth muscle cells (VSMCs), with enhanced effects in cells from spontaneously hypertensive rats (SHRs). The mechanisms (genomic and nongenomic) whereby testosterone induces ROS generation and the role of c-Src, a regulator of redox-sensitive migration, were determined. VSMCs from male Wistar-Kyoto rats and SHRs were stimulated with testosterone (10(-7) mol/L, 0-120 minutes). Testosterone increased ROS generation, assessed by dihydroethidium fluorescence and lucigenin-enhanced chemiluminescence (30 minutes [SHR] and 60 minutes [both strains]). Flutamide (androgen receptor antagonist) and actinomycin D (gene transcription inhibitor) diminished ROS production (60 minutes). Testosterone increased Nox1 and Nox4 mRNA levels and p47phox protein expression, determined by real-time PCR and immunoblotting, respectively. Flutamide, actinomycin D, and cycloheximide (protein synthesis inhibitor) diminished testosterone effects on p47phox. c-Src phosphorylation was observed at 30 minutes (SHR) and 120 minutes (Wistar-Kyoto rat). Testosterone-induced ROS generation was repressed by 3-(4-chlorophenyl) 1-(1...

‣ Avaliação das concentrações de testosterona no pêlo de cães domésticos (Canis lupus familiaris); Evaluation of testosterone concentrations in domestic dogs hair (Canis lupus familiaris)

Guerreiro, Claudia Veronica Calamari
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 25/09/2008 Português
Relevância na Pesquisa
37.043472%
O objetivo do presente estudo foi determinar as concentrações de testosterona no pêlo de cães domésticos, testar dois protocolos diferentes de extração hormonal, comparar os níveis séricos e avaliar as possíveis diferenças de concentração de testosterona no pêlo de acordo com: o sexo; animais castrados e inteiros; região de colheita; tipo e tempo de armazenamento do extrato e coloração da pelagem. Foram utilizados 31 animais adultos, sendo 25 machos e 6 fêmeas, da raça poodle provenientes de canis particulares. O pêlo foi colhido com auxílio de tesoura ou máquina de tosa e armazenados em temperatura ambiente, juntamente com colheita da amostra de sangue. Os protocolos de extração utlizaram 3mL de metanol como solvente por 2 ou 48 horas, os extratos foram secos em ar comprimido, ressuspendidos e armazenados na geladeira ou freezer por até 30 dias. As concentrações foram determinadas por radioimunensaio (RIE). Os testes estatísticos foram realizados utilizando-se o programa computadorizado Statistical Analysis System (SAS). Os resultados mostraram que é possível determinar as concentrações do hormônio testosterona no pêlo de cães. Os dois protocolos de extração de testosterona no pêlo demonstraram-se eficientes...

‣ Testosterona induz migração de células da musculatura lisa vascular de ratos espontaneamente hipertensos por mecanismos dependentes de EROs e ativação da NADPH oxidase via c-Src.; Testosterone induces migration of vascular smooth muscle cells from spontaneously hypertensive rats via c-Src-dependent NADPH oxidase-driven ROS generation.

Chignalia, Andréia Zago
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 27/10/2009 Português
Relevância na Pesquisa
37.074868%
O dimorfismo sexual relacionado à hipertensão arterial surge na adolescência e persiste por toda vida adulta. Homens apresentam maior incidência de doenças cardiovasculares quando comparados a mulheres de mesma faixa etária. O mesmo perfil é observado em modelos animais de hipertensão, nos quais machos apresentam maiores níveis pressóricos quando comparados a fêmeas. Dessa forma, a testosterona é frequentemente relacionada à hipertensão arterial. Entretanto, os mecanismos pelos quais a testosterona exerce efeitos vasculares ainda não estão esclarecidos. O objetivo deste trabalho foi investigar os efeitos da testosterona sobre a geração de espécies reativas de oxigênio (EROs), importantes mediadores do processo hipertensivo, em células da musculatura lisa vascular (CMLV) de ratos normotensos e espontaneamente hipertensos (SHR). Os receptores para andrógenos, as fontes de EROs (papel da NADPH oxidase), bem como os efeitos funcionais celulares (migração celular) relacionados aos efeitos da testosterona também foram analisados. Para tanto, CMLV do leito mesentérico de ratos Wistar (W), Wistar-Kyoto (WKY) e SHR foram isoladas, cultivadas e estimuladas com testosterona 10-7mol/L em diferentes tempos, de acordo com cada protocolo. Sempre que necessário...

‣ Testosterone Regulates Bone Response to Infl ammation

Steffens, J. P.; Herrera, B. S.; Coimbra, L. S.; Stephens, D. N.; Rossa, C.; Spolidorio, L. C.; Kantarci, A.; Van Dyke, T. E.
Fonte: Georg Thieme Verlag Kg Publicador: Georg Thieme Verlag Kg
Tipo: Artigo de Revista Científica Formato: 193-200
Português
Relevância na Pesquisa
37.087468%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Processo FAPESP: 10/09658-0; Processo FAPESP: 10/12021-4; This study evaluated the alveolar bone response to testosterone and the impact of Resolvin D2 (RvD2) on testosterone-induced osteoblast function. For the in vivo characterization, 60 male adult rats were used. Treatments established sub-physiologic (L), normal (N), or supra-physiologic (H) concentrations of testosterone. Forty rats were subjected to orchiectomy; 20 rats received periodical testosterone injections while 20 rats received testicular sham-operation. Four weeks after the surgeries, 10 rats in each group received a subgingival ligature around the lower first molars to induce experimental periodontal inflammation and bone loss. In parallel, osteoblasts were differentiated from neonatal mice calvariae and treated with various doses of testosterone for 48h. Cell lysates and conditioned media were used for the determination of alkaline phosphatase, osteocalcin, RANKL, and osteoprotegerin. Micro-computed tomography linear analysis demonstrated that bone loss was significantly increased for both L and H groups compared to animals with normal levels of testosterone. Gingival IL-1 expression was increased in the L group (p<0.05). Ten nM testosterone significantly decreased osteocalcin...

‣ TESTOSTERONE CHANGES IN PATIENTS WITH LIVER CIRRHOSIS BEFORE AND AFTER ORTHOTOPIC LIVER TRANSPLANTATION AND ITS CORRELATION WITH MELD

NITSCHE,Rodrigo; COELHO,Júlio Cezar Uili; FREITAS,Alexandre Coutinho Teixeira de; ZENI NETO,Clementino; MARTINS,Eduardo
Fonte: Instituto Brasileiro de Estudos e Pesquisas de Gastroenterologia - IBEPEGE ; Colégio Brasileiro de Cirurgia Digestiva - CBCD ; Sociedade Brasileira de Motilidade Digestiva - SBMD ; Federação Brasileira de Gastroenterologia - FBG; Sociedade Brasileira de Hepatologia - SBH; Sociedade Brasileira de Endoscopia Digestiva - SOBED Publicador: Instituto Brasileiro de Estudos e Pesquisas de Gastroenterologia - IBEPEGE ; Colégio Brasileiro de Cirurgia Digestiva - CBCD ; Sociedade Brasileira de Motilidade Digestiva - SBMD ; Federação Brasileira de Gastroenterologia - FBG; Sociedade Brasileira de Hepatologia - SBH; Sociedade Brasileira de Endoscopia Digestiva - SOBED
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2014 Português
Relevância na Pesquisa
37.074868%
Context Hypogonadism is a common clinical situation in male patients with liver cirrhosis. Objectives The aim of the present study was to evaluate the effects of orthotopic liver transplantation on testosterone, free testosterone and sex hormone-binding globulin in male with advanced liver disease and also to determine the relationship of these changes with Model for End-stage Liver Disease (MELD) score. Methods In a prospective study, serum levels of testosterone, free testosterone and sex hormone-binding globulin of 30 male adult patients with end-stage liver disease were measured 2 to 4 hours before and 6 months after orthotopic liver transplantation. Results Total testosterone levels increased after orthotopic liver transplantation and the number of patients with normal testosterone levels increased from 18 to 24. Free testosterone mean level in the pre-transplant group was 7.8 pg/mL and increased to 11.5 pg/mL (P = 0.10) and sex hormone-binding globulin level decreased after orthotopic liver transplantation returning to normal levels in MELD ≤18 - group (A) (P<0.05). Conclusions Serum level changes of testosterone, free testosterone and sex hormone-binding globulin are more pronounced in cirrhotic males with MELD ≤18. Serum levels of testosterone and free testosterone increase and serum levels of sex hormone-binding globulin decrease after orthotopic liver transplantation.

‣ Age-related testosterone decline in a Brazilian cohort of healthy military men

Nardozza Júnior,Archimedes; Szelbracikowski,Sérgio dos Santos; Nardi,Aguinaldo Cesar; Almeida,José Carlos de
Fonte: Sociedade Brasileira de Urologia Publicador: Sociedade Brasileira de Urologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2011 Português
Relevância na Pesquisa
37.06036%
INTRODUCTION: Androgen decline in the aging man has become a topic of increasing clinical relevance worldwide, as the reduction in testosterone levels has been reported to be accompanied by loss of muscle mass, accumulation of central adiposity, impaired mobility and increase risk of bone fractures. Although well-established in studies conducted in developed countries, progressive decline in serum testosterone levels with age has been poorly investigated in Brazil. AIM: To determine the pattern of blood testosterone concentrations decline with age in a cohort of Brazilian healthy military men. MATERIALS AND METHODS: We retrospectively reviewed data on serum testosterone measurements of healthy individuals that had undergone a routine check-up at the Military Biology Institute. Blood samples were obtained early in the morning, and total testosterone concentration was determined using a commercial chemoluminescent immunoassay. Mean values were analyzed in five age groups: < 40, 41 to 50, 51 to 60, 61 to 70, and > 70 years. MAIN OUTCOME MEASURE: Mean total testosterone levels. RESULTS: 1,623 subjects were included in the analysis; mean age was 57 years (24 to 87), and mean testosterone level was 575.5 ng/dL (25.0 to 1308.0 ng/dL). The evaluation of age-related changes in total testosterone levels revealed a progressive reduction in serum levels of this hormone with increasing age. Testosterone levels below 300 ng/dL were reported in 321 participants...

‣ Marriage and motherhood are associated with lower testosterone concentrations in women

Barrett, Emily S.; Tran, Van; Thurston, Sally; Jasienska, Grazyna; Furberg, Anne-Sofie; Ellison, Peter T.; Thune, Inger
Fonte: Elsevier BV Publicador: Elsevier BV
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
37.087468%
Testosterone has been hypothesized to modulate the trade-off between mating and parenting effort in males. Indeed, evidence from humans and other pair-bonded species suggests that fathers and men in committed relationships have lower testosterone levels than single men and men with no children. To date, only one published study has examined testosterone in relation to motherhood, finding that mothers of young children have lower testosterone than non-mothers. Here, we examine this question in 195 reproductive-age Norwegian women. Testosterone was measured in morning serum samples taken during the early follicular phase of the menstrual cycle, and marital and maternal status were assessed by questionnaire. Mothers of young children (age ≤ 3) had 14% lower testosterone than childless women and 19% lower testosterone than women who only had children over age 3. Among mothers, age of the youngest child strongly predicted testosterone levels. There was a trend towards lower testosterone among married women compared to unmarried women. All analyses controlled for body mass index (BMI), age, type of testosterone assay, and time of serum sample collection. This is the first study to look at testosterone concentrations in relation to marriage and motherhood in Western women...

‣ Influence d’une augmentation du taux de testostérone sur les décisions d’approvisionnement chez les diamants mandarins mâles (Taeniopygia guttata)

Le Hô, Mewen
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
Português
Relevância na Pesquisa
37.124746%
Un animal qui s’approvisionne en groupe peut rechercher soi-même sa nourriture (tactique producteur) ou tenter de se joindre à des parcelles déjà découvertes par un autre individu (tactique chapardeur). Bien que les modèles de jeu producteur-chapardeur partent du principe que les gains moyens à l’équilibre associés à chacune de ces tactiques sont égaux et ne dépendent pas des caractéristiques des individus, de plus en plus d’études démontrent que le gain de chaque tactique est influencé par certaines caractéristiques phénotypiques (agressivité, capacités d’apprentissage,…). Dans cette étude, nous nous intéressons aux effets de la testostérone sur le choix des tactiques d’approvisionnement chez les mâles de diamant mandarin (Taeniopygia guttata). La testostérone est connue pour influencer le développement du cerveau et l’agressivité, nous avons donc testé les effets d’une exposition prénatale à la testostérone ainsi que durant l’âge adulte sur le choix des tactiques d’approvisionnement lorsque la nourriture est cryptique ou défendable. Nous avons réalisé deux expériences : nous avons tout d’abord utilisé la longueur du tarse ainsi que la différence entre les longueurs des doigts 2 et 4 comme des indicateurs de l’exposition prénatale à la testostérone puis testé si ces différences morphologiques se traduisent par des différences dans le choix des tactiques dans une condition défendable et une condition cryptique. Nous avons trouvé que le choix des tactiques chez les diamants mandarins était limité par le phénotype. Une exposition précoce à la testostérone au cours du développement prénatal pourrait donc être la cause d’au moins une part de la variation observée dans le choix des tactiques d’approvisionnement. Ensuite...

‣ Endogenous serum testosterone in man: ageing, the metabolic syndrome, functional decline and the role of supplementation

Haren, Matthew Timothy
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado Formato: 1084594 bytes; 370104 bytes; 2890463 bytes; 1020791 bytes; 193907 bytes; application/pdf; application/pdf; application/pdf; application/pdf; application/pdf
Publicado em //2005 Português
Relevância na Pesquisa
37.143887%
This thesis investigates the age - related decline in the various available measures and estimates of serum testosterone levels in men. Testosterone circulates predominantly bound with high affinity to sex - hormone binging globulin ( SHBG ) in plasma ( ~ 60 % ) and with lower affinity to albumin ( < 40 % ) ; approximately 1 - 2 % circulates unbound in plasma. It is the albumin - bound and free fractions ( termed " bioavailable testosterone " ) that are most likely to have biological effects on target tissues. This thesis reports the establishment, validation and derivation of normal ranges for an ammonium sulphate precipitation method for the measurement of bioavailable testosterone in serum. This method is in use by a number of laboratories at present including the laboratory of Professor John Morley at St Louis University with whom we collaborated. Testosterone has been shown, both cross - sectionally and longitudinally, to decline progressively beginning around the age of thirty. Total testosterone declines at approximately 0.4 % per year while bioavailable and free testosterone decline at approximately 1.2 % per year. The mechanisms that may be responsible for this include age - related changes to the hypothalamic - pituitary - testicular axis...

‣ Lower sex hormone-binding globulin is more strongly associated with metabolic syndrome than lower total testosterone in older men: the Health in Men Study

Chubb, P.; Hyde, Z.; Almeida, O.; Flicker, L.; Norman, P.; Jamrozik, K.; Hankey, G.; Yeap, B.
Fonte: Bio Scientifica Ltd Publicador: Bio Scientifica Ltd
Tipo: Artigo de Revista Científica
Publicado em //2008 Português
Relevância na Pesquisa
37.087468%
BACKGROUND: Reduced circulating testosterone and sex hormone-binding globulin (SHBG) are implicated as risk factors for metabolic syndrome. As SHBG increases with age while testosterone declines, we examined the relative contributions of SHBG and testosterone to the risk of metabolic syndrome in older men. METHODS: We conducted a cross-sectional study of 2502 community-dwelling men aged > or = 70 years without known diabetes. Metabolic syndrome was defined using the National Cholesterol Education Program-Third Adult Treatment Panel (NCEP-ATPIII) criteria. Early morning fasting sera were assayed for total testosterone, SHBG and LH. Free testosterone was calculated using mass action equations. RESULTS: There were 602 men with metabolic syndrome (24.1%). The risk of metabolic syndrome increased for total testosterone < 20 nmol/l, SHBG < 50 nmol/l and free testosterone < 300 pmol/l. In univariate analyses SHBG was associated with all five components of metabolic syndrome, total testosterone was associated with all except hypertension, and free testosterone was associated only with waist circumference and triglycerides. In multivariate analysis, both total testosterone and especially SHBG remained associated with metabolic syndrome, with odds ratios of 1.34 (95% confidence interval (CI): 1.18-1.52) and 1.77 (95% CI: 1.53-2.06) respectively. Men with hypogonadotrophic hypogonadism (total testosterone < 8 nmol/l...

‣ Healthier lifestyle predicts higher circulating testosterone in older men: the Health in Men Study.

Yeap, B.; Almeida, O.; Hyde, Z.; Norman, P.; Chubb, S.; Jamrozik, K.; Hankey, G.; Flicker, L.
Fonte: Wiley-Blackwell Publishing Ltd. Publicador: Wiley-Blackwell Publishing Ltd.
Tipo: Artigo de Revista Científica
Publicado em //2008 Português
Relevância na Pesquisa
37.087468%
Objective: Circulating testosterone declines during male ageing, and low testosterone may predispose to ill health. We sought to determine whether greater participation in healthy behaviours predicted reduced risk of subsequent lower circulating testosterone in older men. Design: Cross-sectional analysis of a population-based follow-up study. Participants: 3,453 men aged 65-83 years. Measurements: Lifestyle score, a tally of 8 prudent health-related behaviours, was determined during 1996-1999. Early morning sera collected in 2001-2004 were assayed for total testosterone, sex hormone binding globulin (SHBG) and luteinizing hormone (LH). Free testosterone was calculated using mass action equations. Results: Mean (±SD) time between collection of lifestyle data and blood sampling was 5.7±0.9 years. Lifestyle score correlated with subsequent total testosterone (r=0.06, p<0.001) and SHBG (r=0.07, p<0.001), but not free testosterone (r=0.03, p=0.08) or LH (r=-0.03, p=0.12). In multivariate analyses, higher lifestyle scores (4 and above) predicted reduced risk of total testosterone and SHBG in the lowest quartile of values. For the highest category (≥7), odds ratio (95% CI) for total testosterone and SHBG in the lowest quartile were 0.37 (0.18-0.77) and 0.26 (0.13-0.54) respectively. Lower lifestyle scores including and excluding Body Mass Index (BMI) predicted higher risk of total testosterone and SHBG in the lowest quartiles. Conclusions: In men >65 years old...

‣ Serum testosterone levels correlate with haemoglobin in middle-aged and older men

Yeap, Bu B.; Beilin, J.; Knuiman, M.; Olynyk, J. K.; Bruce, D. G.; Milward, E. A.
Fonte: Blackwell Publishing Asia Publicador: Blackwell Publishing Asia
Tipo: Artigo de Revista Científica
Publicado em //2009 Português
Relevância na Pesquisa
37.098513%
Background: Lower testosterone levels are associated with anaemia in older men and women. The relation between testosterone and haemoglobin (Hb) in younger and middle-aged men is less well defined. The aim of the study was to examine the association between testosterone and Hb levels in men spanning middle to older ages. Methods: A cross-sectional analysis of 492 men aged 30.7–94.5 years from the Busselton Health Survey, Western Australia, was carried out. Haemoglobin (Hb), early-morning serum total testosterone and sex hormone-binding globulin (SHBG) were measured. Free testosterone was calculated using mass action equations. Results: Haemoglobin correlated to total and free testosterone concentrations (r= 0.13, P= 0.003 and r= 0.20, P < 0.001, respectively). Hb and SHBG were inversely correlated (r=−0.14, P= 0.001). Hb increased across lowest to highest quartiles of total testosterone (P= 0.02) and free testosterone (P < 0.001), but not SHBG. After adjusting for age, waist circumference, smoking status, alcohol consumption, renal function and ferritin, total testosterone was associated with Hb (β= 0.037, P= 0.003) as was free testosterone (β= 2.32, P < 0.001), whereas SHBG was not associated. Conclusion: Testosterone concentration modulates Hb levels in community-dwelling men across a wide age range. Further studies are needed to clarify implications of this association between testosterone and Hb in men.; B. B. Yeap...

‣ The relationship between sleep disorders and testosterone in men

Wittert, G.
Fonte: Wolters Kluwer Publicador: Wolters Kluwer
Tipo: Artigo de Revista Científica
Publicado em //2014 Português
Relevância na Pesquisa
37.087468%
Plasma testosterone levels display circadian variation, peaking during sleep, and reaching a nadir in the late afternoon, with a superimposed ultradian rhythm with pulses every 90 min reflecting the underlying rhythm of pulsatile luteinizing hormone (LH) secretion. The increase in testosterone is sleep, rather than circadian rhythm, dependent and requires at least 3 h of sleep with a normal architecture. Various disorders of sleep including abnormalities of sleep quality, duration, circadian rhythm disruption, and sleep-disordered breathing may result in a reduction in testosterone levels. The evidence, to support a direct effect of sleep restriction or circadian rhythm disruption on testosterone independent of an effect on sex hormone binding globulin (SHBG), or the presence of comorbid conditions, is equivocal and on balance seems tenuous. Obstructive sleep apnea (OSA) appears to have no direct effect on testosterone, after adjusting for age and obesity. However, a possible indirect causal process may exist mediated by the effect of OSA on obesity. Treatment of moderate to severe OSA with continuous positive airway pressure (CPAP) does not reliably increase testosterone levels in most studies. In contrast, a reduction in weight does so predictably and linearly in proportion to the amount of weight lost. Apart from a very transient deleterious effect...

‣ Safety and efficacy of a testosterone metered-dose transdermal spray for treating decreased sexual satisfaction in premenopausal women - a randomized trial

Davis, S.; Papalia, M.A.; Norman, R.; O'Neill, S.; Redelman, M.; Williamson, M.; Stuckey, B.; Wlodarzcyk, J.; Gard'ner, K.; Humberstone, A.
Fonte: Amer Coll Physicians Publicador: Amer Coll Physicians
Tipo: Artigo de Revista Científica
Publicado em //2008 Português
Relevância na Pesquisa
37.087468%
BACKGROUND: It is not known whether premenopausal women who report low sexual satisfaction and have low circulating testosterone levels will benefit from testosterone therapy. OBJECTIVE: To evaluate the effects of exogenous testosterone in premenopausal women reporting diminished sexual function. DESIGN: Randomized, double-blind, placebo-controlled, dose-ranging trial. SETTING: 6 Australian medical centers. PATIENTS: 261 women age 35 to 46 years who reported a decrease in satisfying sexual activity relative to their younger years and had a morning serum free testosterone level less than 3.8 pmol/L (<1.1 pg/mL). INTERVENTION: 3 different doses of testosterone administered by a metered-dose transdermal spray for 16 weeks or placebo. MEASUREMENTS: The primary outcome was the mean number of self-reported satisfactory sexual events (SSEs) over 28 days at week 16. The frequency of SSEs, total number of sexual events (every 4 weeks), scores from the modified Sabbatsberg Sexual Self-Rating Scale and the Psychological General Well-Being Index, and safety variables were also measured. RESULTS: The number of SSEs increased during the treatment period in the active treatment groups and the placebo group. The mean number of SSEs over 28 days at week 16 was statistically significantly greater for women treated with the intermediate dose of testosterone therapy (one 90-microL spray) than for women treated with placebo. The least-squares mean was 2.48 versus 1.70 SSEs...

‣ Effect of active immunization against testosterone on plasma gonadotrophin concentrations, spermatogenic function, testicular blood flow epididymis mass and mating behaviour in adult rams

Setchell, B.
Fonte: Blackwell Scientific Publications Publicador: Blackwell Scientific Publications
Tipo: Artigo de Revista Científica
Publicado em //1995 Português
Relevância na Pesquisa
37.06036%
The long-term effects of active immunization against testosterone were studied in rams, with particular reference to blood concentrations of gonadotrophin and testosterone, spermatogenesis, testis blood flow and mating behaviour. Ten 18-month-old Merino rams, kept on pasture, were studied for 1 year. Every 2 months, five rams received injections of BSA in Freund's adjuvant and five other rams were treated with testosterone-3(o-carboxymethyl)oxime-BSA as immunogen. Anti-testosterone antibodies (mean titre: 1:4484 +/- 582, after boosters) were maintained in the circulation, with the help of regular booster injections. In time, immunization reduced live mass in testosterone-immunized rams; however, there was no effect on testicular volume throughout the whole study. In testosterone-immunized rams, significantly higher concentrations of gonadotrophins were found in jugular venous plasma, as well as increased concentrations of total plasma testosterone. LH pulse frequency, amplitude and nadir were increased significantly in testosterone-immunized rams. After 12 months of immunization, no differences were found in the number of spermatozoa per ejaculate, in daily sperm production or in testis mass between the two groups of rams; however...

‣ Effect of 12 month oral testosterone on testosterone deficiency symptoms in symptomatic elderly males with low-normal gonadal status

Haren, M.; Chapman, I.; Coates, P.; Morley, J.; Wittert, G.
Fonte: Oxford Univ Press Publicador: Oxford Univ Press
Tipo: Artigo de Revista Científica
Publicado em //2005 Português
Relevância na Pesquisa
37.087468%
BACKGROUND: Relative androgen deficiency in ageing males is assumed to have adverse health effects. This study assessed the effect of 12 months' standard dose, oral testosterone, on symptoms attributed to testosterone deficiency in older men with plasma testosterone levels in the low-normal range for young men. METHODS: Testosterone undecanoate (TU, 80 mg bid) or placebo was administered for one year to 76 healthy men, 60 years or older, with a free testosterone index (FTI) of 0.3-0.5 and significant symptoms on a questionnaire designed to evaluate androgen deficiency (ADAM). The ADAM was completed at baseline, 6 and 12 months. Hormone and safety data were collected at baseline, 1, 3, 6 and 12 months. RESULTS: After 12 months, plasma total testosterone was unchanged in both groups and sex hormone binding globulin decreased in the testosterone group (P = 0.01). FTI and calculated bioavailable testosterone (cBT) were greater in the testosterone group as compared with the placebo group (P = 0.021 and 0.025, respectively). There was no significant difference in total symptom score between testosterone and placebo groups after 12 months of oral TU. However, there were trends toward improvements in sadness/grumpiness (P = 0.063), reduced erection strength (P = 0.059) and decreased work performance symptoms (P = 0.077)...

‣ Influence de la testostérone sur les paramètres électrocardiographiques des hommes et des femmes

Gayard, Marion
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
Português
Relevância na Pesquisa
37.098513%
Les hommes et les femmes diffèrent devant la survenue de plusieurs types d’arythmies cardiaques. Ainsi, la prévalence des fibrillations auriculaires, ou celle du syndrome de Brugada est plus élevée chez les hommes, tandis que les femmes sont plus susceptibles de développer des torsades de pointe. La survenue de ces arythmies pourrait être affectée par l’existence de disparités entre les sexes au niveau de l’activité électrique cardiaque normale. Des différences ont d’ailleurs été décrites dans les paramètres électrocardiographiques des hommes et des femmes, et notamment au niveau des paramètres traduisant la phase de repolarisation ventriculaire. Par ailleurs, plusieurs études cliniques et expérimentales ont permis d’avancer que les androgènes pourraient contribuer à expliquer les différences homme-femme observées dans la repolarisation ventriculaire. Leur influence sur les autres paramètres électrocardiographiques a toutefois reçu peu d’attention jusqu’à aujourd’hui. Dans ce contexte, l’objectif de ce travail était de mieux comprendre l’implication de la testostérone dans les différences sexuelles observées au niveau de l’électrocardiogramme. En travaillant à partir d’une cohorte de volontaires sains...

‣ The annual testosterone profile in cooperatively breeding superb fairy-wrens, Malurus cyaneus , reflects their extreme infidelity

Peters, Ann; Astheimer, Lee B; Cockburn, Andrew
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
37.074868%
Superb fairy-wrens are cooperatively breeding birds that combine stable, socially monogamous pair bonds and high levels of paternal care, with extreme levels of extra-pair mating and high levels of sexual competition. Our aim was to determine which testosterone correlates would prevail in such a life history that combines features that are conventionally associated with divergent hormone profiles. Unlike the situation in other species with monogamous pair bonds and high levels of paternal care, testosterone was elevated for a very long period of several months During breeding there was a broad peak in testosterone followed by a gradual decline: this resembles the profile found in polygynous and promiscuous species. We found that three factors correlated with testosterone: development of the sexually selected nuptial plumage, social status and extra-group mating opportunities. Testosterone started increasing months prior to breeding, when the males that are later preferred as extra-group sires develop their nuptial plumage. Although these males did not have higher testosterone levels during breeding, they sustained high testosterone for much longer, and this might lend reliability to this sexual signal. Dominant males in groups had higher testosterone than pair-dwelling males and subordinate helpers. This was not due to differences in age...

‣ Testosterone treatment is immunosuppressive in superb fairy-wrens, yet free-living males with high testosterone are more immunocompetent

Peters, Ann
Fonte: Royal Society of London Publicador: Royal Society of London
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
37.098513%
The immunocompetence handicap hypothesis proposes that the immunosuppressive effect of testosterone enforces honesty of sexual signalling via a physiological trade-off between signal intensity and immunocompetence. However, evidence that testosterone is immunosuppressive is scant, particularly in birds. I studied the correlation between immunocompetence and testosterone in superb fairy-wrens (Malurus cyaneus), a species with intense intersexual selection. Males are seasonally dichromatic and testosterone increases during the moult from dull brown eclipse plumage into bright nuptial plumage. I determined the primary antibody response to immunization with sheep red blood cells (SRBCs) in (i) control and testosterone-implanted males in captivity, and (ii) a cross-section of free-living males with basal and elevated testosterone (in eclipse plumage, moulting and in nuptial plumage). Experimental treatment with testosterone decreased the likelihood of an antibody response to SRBCs in captive birds. In contrast, free-living males which had acquired the nuptial plumage and had naturally elevated testosterone were more likely to respond to SRBCs than males in eclipse plumage with basal testosterone levels. Thc association between higher immunocompetence and higher immunosuppressive testosterone could arise if both are positively correlated with male phenotypic quality. In addition...