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<p>There is a prevalent belief that acute hormone responses to resistance exercise mediate adaptations in skeletal muscle hypertrophy; however, there is little supporting evidence. We conducted studies to examine the relationship between acute hormonal increases after resistance exercises and subsequent changes in muscle anabolism.</p> <p>We tested the hypothesis that exercise-induced responses of anabolic hormones—growth hormone (GH) and testosterone—would enhance rates of myofibrillar protein synthesis (MPS) after an acute bout of resistance exercise, and would augment muscle hypertrophy after training. We concluded, however, that resistance exercise-induced increases in putative anabolic hormones do not enhance MPS or hypertrophy.</p> <p>We also examined whether rates of MPS would be attenuated in women (compared with men) after resistance exercise, due to their lack of post-exercise testosteronemia. We reported similar increases in MPS in men and women; post-exercise testosterone responses in women, which were 45-fold lower than men, did not attenuate elevations in MPS.</p> <p>Collectively, our work leads to the conclusion that the acute rise in hormones such as testosterone and GH has very little bearing on MPS and hypertrophy responses to resistance exercise. Instead, the rise in these hormones appears to be a non-specific response to exercise stress rather than a response that is important for muscle anabolism. Contrary to widely used principles, our data suggests that exercise programs should not be designed based on nuances in the post-exercise hormonal milieu. Alternatively, understanding local mechanotransduction, which is directly linked to muscle fibre loading, will reveal the processes that drive human exercise-mediated muscle hypertrophy.</p> / Doctor of Philosophy (PhD)

One unresolved issue in the study of cooperative breeding is why individuals that delay their own reproduction assist others in raising young. Red-cockaded woodpecker helpers may again future indirect fitness benefits by increasing survival of breeders, who produce offspring related to the helper in the future. Breeder survival may be enhanced because of general benefits of group living, either because of the helper's own presence or because helping increases the production of fledglings. I demonstrate that breeder survival increases in the presence of helpers and additional young. Helpers may also reduce the workload of the breeder, and this may increase breeder survival as well. I show that breeders spend less time incubating and provisioning young when a helper is present. Helpers may also gain fitness benefits if once they become breeders, they are assisted by young they previously helped raise. Expected frequencies of reciprocal exchange of helping are low (2%). Slightly higher observed frequencies may be accounted for by preferential helping of kin and effects of territory quality. Reciprocity occurs no more often than expected among helpers unrelated to the young they help raise suggesting that young males do not preferentially helper former care-givers. i conclude that helpers do not gain fitness benefits from reciprocity. I examined the proximate causes of delayed breeding and helping behavior by measuring plasma testosterone (T) and prolactin (PRL) concentrations in female breeders, male breeders, and male helpers during different stages of the reproductive cycle. Among male breeders and helpers, T is low during the nonbreeding stage, peaks during copulation and declines during the incubation and nestling-provisioning stages. Helpers appear physiologically capable of reproducing: their T concentrations are equal those of breeders. Helpers unrelated to the breeding female have higher T than helper related to her. Sexual inactivity by male helpers is best explained by behavioral suppression. Female breeder, male breeder, and male helper PRL was equal and increased from the nonbreeding stage through the copulation and incubation stages. During the nestling provisioning stage, male breeder and male helper PRL declined, while female PRL continued to increase. I conclude that the physiological bases of helping behavior and parental behavior are the same. / Ph. D.

Testosterone is a steroid and anabolic hormone found in all mammals. Previous research indicates that testosterone levels correlates with physical capacities related to physical performance. However, these studies refers only to men and boys. The aim of present study was therefore to investigate the potential relationship between body composition, strength, power and endurance capabilities in relation to blood levels of testosterone and DHEAS in young female football players. Seventeen female elite football (age: 15,4 ± 0,6, body mass: 57,2 ± 7,4kg, height 1,65 ±0,04m) players volunteered for the study. Morning levels of testosterone were plotted against results of Dual-energy X-ray absorptiometry, Biodex isokinetic dynamometer, maximal counter movement jump, drop jump, 10 and 20 meters sprints and aerobic fitness (Yo-Yo intermittent endurance test). Testosterone levels were significant correlated with DHEAS as well as bone density (BMD) in L1-L4 (p &lt;0,01) and whole body (WB) BMD (p &lt;0,05). DHEAS also correlated with BMD in L1-L4 and WB (p &lt;0,05). No correlations were found between testosterone, DHEAS and performance capacities. These results suggest that DHEAS predict the level of testosterone and BMD in young women. However, more research is needed to clarify the relationship between testosterone, DHEAS and physical capacities in a larger group of women.

Background. Endocrine disruptors (EDC) are exogenous compounds that mimic the action of natural hormones and alter the normal endocrine system. Life-long chronic exposure to Bisphenol A (BPA), a putative EDC, has been linked with risk of metabolic disorders in epidemiological studies. Objectives. The aim was to study the human health effects of exposure to BPA, using an integrated approach combining environmental epidemiology and toxicology. Methods. Urinary levels of BPA exposure were measured in participants of the InChianti longitudinal study, a representative population-based study of Italian adults, at the Baseline (1998-00) and nine years later (3rd Wave, 2007-09). Hormones levels and the gene expression of specific target genes were the end points considered. Results were validated in laboratory studies on a human leukemic T-cell line (Jurkat cells). Results. In general, urinary BPA (uBPA) concentrations were higher among men and younger respondents, and within subjects uBPA concentrations were correlated (r=0.58; p=0.013, model adjusted for age, sex, urinary creatinine). At baseline, uBPA concentration were associated with higher total testosterone concentrations in men (β = 0.05; 95% CI, 0.02–0.08). In the 3rd wave, gene expression analysis revealed positive associations between uBPA concentrations and ESR2 (estrogen receptor beta) expression (β=0.18; 95% CI: 0.04, 0.32) and ESRRA (estrogen related receptor alpha) expression (β= 0.17; 95% CI: 0.02, 0.32). In a following in vitro study, BPA exposure (0.001-1 micro molar) led to enhanced expression of ESRRA and ESR2 in Jurkat cells over a period of 72 hours. Conclusions. Results indicate that BPA is bioactive in the human body and is able to alter circulating hormone concentrations and estrogen receptor/estrogen-related receptr gene expression. In particular, given the role of ERRα as a major control point for oxidative metabolism and heart development, this research provides indications on the possible molecular mechanisms of action of BPA in metabolic diseases.

Hormonal aspects of antler growth regulation Erika Kužmová Abstract Deer antlers are the only mammalian organ that completely regenerates and therefore they became an object of rising interest as a potential model for bone growth and development. In recent years, it has been confirmed that annual regeneration of the antler is initiated from the stem cell niche localised in the pedicle periosteum. Antlers grow to the length at the tip. Only a little is known about endocrine stimulation of antler growth and some discrepancy has arisen between in vivo and in vitro studies over the decades. As the secondary sexual character, the antler cycle timing and growth are linked to seasonal levels of testosterone. Since the levels are at their minimum during the antler growth phase, according to many mainly in vitro studies, insulin-like growth factor-1 (IGF-1) tends to be accepted as the "antler stimulating hormone". Since the conclusion about the role of IGF-1 was contradictory to previous opinions and also in contrast with our own experience, we aimed to verify the role of IGF-1 in vitro. Our ex- periments were based on existing in vivo studies demonstrating the importance of testosterone, even in its low levels, and on the hypothesis that testosterone should be the "antler stimulating hormone". We performed in vitro...

The effect of 17α-methyltestosterone a 17β-estradiol on sex of livebearer fish Poecilia reticulata and P. wingei was studied. Solution of 2.5 mg testosterone was added in the aquarium the first and fifteenth day after delivery of new fry. Estrogen was administered in food to gravid females (400 mg per 1 kg food). Sex of all individuals was determined in one, two and three months. Administration of neither testosterone nor estrogen caused sex reversal; in the second case reproduction of almost all females was stopped.

Post-exercise carbohydrate-protein consumption and tapering periods during training periodisation have been proposed as effective recovery strategies in several sports; however, limited attention has been given to judo. Apart from training and recovery, effective competition performance can also be influenced by several stimuli on the competition day, which may be manifested as distinct endocrine responses. The main objective of this thesis was to influence effective competition performance in judo, through examining strategies that can aid recovery from intense exercise/training and examining endocrine responses to competition. Three experimental studies on recovery were completed (chapters 3-5) followed by an observational study on a judo competition day (chapter 6) in elite, national level, male judo athletes. Studies 1 and 2 examined the effects 1000 ml of post-exercise chocolate milk (CM) consumption compared with water (W) following an intense judo training session (chapter 3) and five days of intense judo training with concomitant weight loss (chapter 4) on the recovery of salivary cortisol (sC), salivary testosterone (sT), salivary testosterone:cortisol (sT/C) ratio, salivary secretory IgA (SIgA) absolute concentrations and secretion rate, muscle soreness, mood state and judo-related performance. Study 1 (n=10) did not show any beneficial effects of acute CM consumption on aspects of recovery of any of the measured variables, except for a lower perception of soreness (p<0.05) and a tendency for better push-up performance (p=0.09). Study 2 (n=12) showed that post-exercise CM consumption resulted in significantly lower sC levels, a tendency for higher sT/C ratio (p=0.07), better judo-related performance, lower muscle soreness and reduced mood disturbance (p<0.05) with W. In addition, post-exercise consumption of CM resulted in a 1.1% decrease in body weight, indicating that CM is an effective recovery beverage during periods of intense judo training without affecting intentional weight loss. Study 3 (n=11) examined the effects of a 2-week exponential taper following 2 weeks of intense judo training on recovery of the aforementioned variables. Within 12 days of tapering there were evidence of enhanced performance, lower sC, higher sT and higher sT/C ratio, higher SIgA secretion rate, lower muscle soreness and reduced mood disturbance, indicating that a tapering period of ~10 days is an effective recovery strategy for optimising judo performance. Study 4 observed the responses of sC, sT, SIgA absolute concentrations and SIgA secretion rate and self-measured anxiety state in the winners (n=12) and losers (n=11) of a judo competition. Winners presented significantly higher morning sC levels and higher cognitive anxiety in anticipation of the competition, as well as a tendency for higher SIgA secretion rate (p=0.07) and significantly higher saliva flow rate mid-competition. These findings indicate that winners experienced higher arousal levels and that anticipatory sC might have some predictive value for winning performance in judo. This thesis concludes that nutrition and tapering are both important aspects of effective recovery; CM can be an effective nutritional recovery aid during periods of intense judo training and tapering for 7-12 days can optimise judo performance and can be implemented prior to competitions. In addition, elevated sC levels in anticipation of a judo competition and higher levels of arousal could have some predictive value for winning performance in judo. Further research could focus on strategies to increase levels of arousal in anticipation of competition.

Dentre os diversos fatores que provocam diminuição no desempenho reprodutivo, a degeneração testicular térmica é o motivo mais freqüente de baixa fertilidade em Bos taurus no Brasil. Baseados nos efeitos sobre a secreção de hormônios hipofisários e gonadais, o GH vem sendo estudado para o tratamento da infertilidade masculina. Um delineamento experimental tipo blocos ao acaso utilizou dezesseis touros adultos submetidos a 4 tratamentos em esquema fatorial 2x2 (0 e 96 horas de insulação testicular, 0 e 1,2 mg bST/kg PV), com o objetivo de testar os efeitos da bST no tratamento de touros submetidos a insulação testicular. Motilidade, alterações de acrossoma, defeitos de cauda e cabeça, gota protoplasmática proximal e defeitos espermáticos totais aumentaram em conseqüência da insulação testicular. As concentrações seminais de Testosterona foram temporariamente diminuídas em resposta a insulação testicular. A ocorrência de gota protoplasmática distal, anomalias de peça intermediária e concentrações seminais de IGF1 não foram afetadas pela insulação testicular. A somatotropina recombinante bovina não afetou as características espermáticas ou concentrações seminais de Testosterona e IGF1. / Testicular heat degeneration is the most common cause of poor fertility of Bos taurus bulls in the tropics. The Growth Hormone has been studied in man infertility treatment with some progress. A randomly blocks experimental design used 16 mature bulls allotted in 4 treatments in a 2x2 factorial arrangement (0 e 96 hours of scrotal insulation, 0 e 1,2 mg bST/kg BW) was performed to asses the effects ob bulls submitted to scrotal insulation. Motility, abnormal acrosome, tail and head defects, proximal droplet, and abnormal sperm increased, and seminal plasma Testosterone was temporally increased in response to scrotal insulation. Distal droplet, midpiece and seminal plasma IGF1 were not affected by bST. The bST did not affect sperm characteristics or seminal Testosterone and IGF1.