The importance of muscle glycogen as a fuel source during exercise has been well documented. Maintaining a high glycogen level before and during activity is a major determinant of performance. Elevation of glycogen levels during recovery from both aerobic and anaerobic bouts of exercise is critical. The purpose of this investigation was to determine the effect of a solid carbohydrate feeding on glycogen resynthesis following aerobic and anaerobic exercise. Eight male cyclists were recruited for this investigation. One hour ride trial, 70 % VO2max followed with feeding (HRY), one sprint trial followed with feeding (SPY), and one sprint trial followed with no feeding (SPN) were randomly performed and separated by ten days. Feeding trials consisted of a solid CHO source (1g CHO per kg bw per hr) fed for four hours of recovery following one hour of passive recovery with no food. Muscle biopsies were obtained immediate post and at six hours of recovery. Bloods were collected at 1, 4, and 30 minutes of recovery for lactate determination. Muscle specimens were analyzed for glycogen and lactate. Muscle glycogen (mmol • kg protein') levels post exercise for HRY, SPN, and SPY trial were 336.9±48.1, 481.0±47.0, and 417.5±26.4, respectively with HRY significantly lower than SPN. The increase in muscle glycogen six hours post-exercise for HRY, SPN, and SPY trials were 117.9±24.8, 29.5 ±22.2, and 207.2 ±20.4, respectively, which were all significantly different (P < 0.05). Blood lactate at + 1 minute for HRY, SPN, and SPY trials were 3.4±.5, 20.6±1.2, and 19.9±1.3 mM, respectively. These data suggest that an athlete training twice during the day with both anaerobic and aerobic components will have greater muscle glycogen available later in the day if anaerobic training is completed first in the day, providing adequate carbohydrate is consumed between bouts. / School of Physical Education

Several studies have reported that rating of perceived exertion (RPE) covaries more with blood lactate concentration (BLC) than other measures of relative exercise intensity. If BLC is used as the intensity criterion, then RPE could be used as a valid tool for exercise prescription. However, few have shown the relationship between RPE and BLC across a variety of graded exercise tests (GXTs) and exercise training settings. The purpose of this study was to determine if differences exist in RPEs at matched BLC between two GXTs and steady state exercise in the field setting. Thirteen healthy males (25 ± 5.3 yrs) completed two maximal treadmill protocols (Bruce and Balke) and one steady state exercise trial on a treadmill at two intensities which lasted approximately 7 minutes each. The intensities (40% & 70% max heart rate reserve) were below and above their ventilatory threshold. RPEs were recorded during the last minute of each workload of the field trial (FT). Immediately following the end of each workload, blood samples were collected for BLC analysis. RPEs from the FT were compared with RPEs from the GXTs at matched BI-Cs using a repeated measures ANOVA across exercise trials. The results show that there were no significant differences in RPEs at a matched BLC of 1.5 mM between the FTand and the Bruce and Balke GXT at the lower intensity, with the RPEs being 9.6 ± 1.7, 9.8 ± 2.6, and 10.2 ± 2.4, respectively. However, at the higher intensity, RPEs at a matched BLC of 3.0 mM were significantly different, with the FT < Bruce < Balke (11.9 ± 1.9, 13.5 ± 2.2 and 15.2 ± 2.0, p < 0.05). These results suggest that the relationship between RPE and BLC established during a GXT may not be transferable to the exercise training setting at exercise intensities in the typical prescription range of 50-85%. Therefore, using RPE for exercise prescription may not be an effective method for regulating exercise intensity according to BLC. / School of Physical Education

A estivação é caracterizada como um conjunto de alterações fisiológicas e comportamentais relacionadas com a redução do metabolismo e a permanência em micro-habitats específicos durante a fase de estiagem. Na caatinga brasileira foram observadas ao menos três espécies que estivam, sendo duas da família Leiuperidae, Pleurodema diplolistris e Physalaemus albifrons e uma da família Cycloramphidae, Proceratophrys cristiceps. Ainda que encontradas no mesmo micro-habitat durante a estivação, estas três espécies exibiram padrões distintos de alteração do desempenho locomotor entre as duas estações marcantes do ano (seca e chuvosa). Enquanto P. diplolistris reduziu em cerca de 47% a velocidade de seu desempenho locomotor durante a fase de estiagem, as outras duas espécies, P. cristiceps e P. albifrons, reduziram cerca de 87 e 83%, respectivamente. Mais ainda, apenas P. diplolistris exibiu mudança de profundidade ao longo da estiagem. A redução da taxa metabólica aeróbia foi de aproximadamente 50% para as três espécies. A comparação entre as estações marcantes do ano ainda revelou que as três espécies estudadas apresentam diferentes padrões de alteração na concentração de substrato energéticos e na atividade de enzimas representativas do metabolismo energético no fígado e musculatura dos membros posteriores. A manutenção hídrica também foi diferente entre as três espécies, o que indica a ocorrência de estratégias diversas de regulação hídrica / Estivation is defined as a set of physiological and behavioral changes associated to decreased metabolism and permanence in specific microhabitats during the dry season. In the Brazilian Caatinga was observed at least three estivating species: Pleurodema diplolistris and Physalaemus albifrons (Leiuperidae) and Proceratophrys cristiceps (Cycloramphidae). Although found in the same micro-habitat during aestivation, these three species differ in the variation patterns of locomotor performance when compared between the two seasons (dry and rainy season). During the dry phase, speed in P. diplolistris is reduced by about 47% whereas in P. cristiceps and P. albifrons values decrease by 87% and 83%, respectively. Moreover, only P. diplolistris exhibited changes of depth along the drought. The reduction of aerobic metabolic rate was of approximately 50% for the three species. The comparison between seasons also revealed that the three species differ in relation to the variation patterns of the concentration of substrate energy and activity of representative enzymes of energy metabolism in the liver and muscles of the hindlimb. The water maintenance was also different among the three species, indicating the occurrence of several strategies of hidric regulation

A participação do fígado na homeostasia da glicose materna ainda não está esclarecida. Este estudo avaliou a produção hepática de glicose em ratas prenhes e controle bem como algumas das principais vias metabólicas hepáticas envolvidas nas alterações metabólicas mediadas pelo fígado ao final do período de prenhez em ratas. Houve diminuição do conteúdo de glicogênio hepático e glicose circulante em ratas prenhes. A taxa de gliconeogênese diminuiu em prenhes assim como o conteúdo de IR e sua fosforilação em tirosina mediante estímulo com insulina, porém a fosforilação em serina da AKT e o conteúdo e expressão gênica da PEPCK, mantêm-se como em controles. Há aumento do conteúdo de PTP1B e de sua associação ao IR na presença de insulina. Houve diminuição do conteúdo de G6Pase, AMPK total e da fosforilação da AMPKa/1 e, conseqüentemente, da fosforilação da ACC em ratas prenhes. Há aumento de triglicérides circulantes e diminuição de triglicérides no tecido hepático. Aumenta a expressão gênica da FAS e diminuem as expressões de G-6-Pase, MEs, LXR, SREBP1 e PFK. Os resultados indicam não haver resistência à insulina no fígado de ratas prenhes e que a atividade metabólica hepática no período está voltada para a síntese de novo de ácidos graxos. / The involvement of the liver in maternal glucose homeostasis is still unclear. This study evaluated the hepatic glucose production in pregnant rats and some of the hepatic metabolic pathways involved in metabolic disorders mediated by the liver in late pregnancy.There was a decrease in liver glycogen content and plasma glucose in pregnant rats. The rate of gluconeogenesis decreased as well as the contents of IR tyrosine phosphorylation after insulin stimulus, but the pSer-AKT, PEPCK, SHP2 contents, SHP2-IR association and the expression of PEPCK remained unaltered. The content of PTP1B and its association with IR decreases in the presence of insulin. The content of G6Pase, AMPK and the phosphorylation of AMPK a/1 and consequently the phosphorylation of ACC decreases in liver from pregnant animals. Triglyceride levels and the expression of FAS was increased in pregnant rats whereas the triglycerides reduced in the liver. The expression of G-6-Pase, MEs, LXR, SREBP1 and PFK decreased in the liver of pregnant rats. The results indicate no insulin resistance in the liver of pregnant rats, and that hepatic metabolic activity in this period is focused on de novo fatty acids synthesis.

Ces travaux de thèse sont focalisés sur l’étude de trois adipocytokines (adiponectine, visfatine et chémérine) chez des espèces dont les anomalies du métabolisme énergétique sont associées à des désordres de la fonction de reproduction. Nos résultats montrent des effets du régime alimentaire sur le métabolisme lipidique et glucidique et de manière moins prononcée sur les fonctions de reproduction chez la vache laitière et la poule reproductrice de souche chair. Ces effets ont en partie été associés aux profils d’expression de l’adiponectine, la visfatine et la chémérine. De plus, nous avons mis en évidence une surexpression du système chémérine/CMKLR1 dans le liquide folliculaire et dans les cellules ovariennes de patientes atteintes du syndrome des ovaires polykystiques associé ou non à une obésité. D’une part, ces découvertes révèlent la possibilité de considérer ces adipocytokines comme de potentiels biomarqueurs de l’évaluation de la croissance, de l’état d’engraissement et de fertilité dans les élevages agricoles. D’autre part, elles suggèrent une potentielle implication de la chémérine dans la régulation des fonctions ovariennes chez la femme. / This thesis is focused on the study of three adipokines (adiponectin, visfatin and chemerin) in species that develop abnormalities of energy metabolism associated with reproductive disorders. Our results have shown some diet effects on the lipid and carbohydrate metabolisms and in a less extend, on the reproductive functions in dairy cows and broiler hens. These effects were partly associated with the expression profiles of adiponectin, visfatin and chemerin. In addition, we have demonstrated overexpression of the chemerin/CMKLR1 system in follicular fluid and in ovarian cells of patients with polycystic ovarian syndrome, with or without obesity. First, these findings reveal the possibility of considering these adipokines as potential biomarkers for evaluating growth, fattening status and fertility in agricultural farms. On the other hand, they suggest a potential involvement of chemerin in the regulation of ovarian functions in women.

Rates and energies of consumption (C), egestion (F), assimilation (A), respiration (R), growth (Pg), production of exuviae (Pev), and production of egg masses (Pr) and associated efficiencies, and the effects of seasonal temperature, weight and metamorphic stage upon these factors were examined for a typical individual and cohort of Corydalus cornutus (L.) from a stream in North-Central Texas (330 23'N, 97*5'W). Dobson flies are apparently univoltine in the study area, with 11 larval instars. Emergence, oviposition and hatching occur from late May to August. The typical dobson fly hatches in mid-June, grows rapidly until November, and resumes rapid growth in March, reaching full adult size prior to leaving the stream to pupate in early June. Adult females must feed to provide energy to yolk eggs, produce egg-mass coverings and continue somatic maintenance during their week of reproductive endeavors. Metabolic compensation enables larval dobson flies to maintain preferred and fairly constant rates of R during winter (201-451 pl g-1 h~1; 5-15 C) and summer (985-1173 pl g- h1; 20-30 C); with a seasonal acclimatization change point between 15-20 C. Reduction of rates of R through undercompensation during the winter when food is scarce and through partial compensation at high temperatures during the summer conserves energy which is allocated to P, resulting in high ratios of P/R (1.94) and P/A (66%) for the individual larva and, to a lesser degree, for the cohort (P/R = 1.07, P/A = 52.3%, P/B = 9.96). Rates of C, F, A and R, but not assimilation efficiency, were influenced by temperature and size. The energy budget for a typical dobson fly during the 47 wk as a larva was: C = 4167, A = 3442, F = 725, Pg = 2075, Pev = 198, and R = 1169. Ova respired 0.107 cal wk-1, prepupae 357 cal wk~ 1 , male pupae 509 cal wk~ 1 , female pupae 454 cal wk~1 , male adults 625 cal wk-l1 and female adults 735 cal wk-1 . The prepupa and pupa shed exuviae of 144 cal and 120 cal respectively. The average female produced 667 cal of eggs and 185 cal of egg-case material, which totaled 54% of adult female A. The annual energetics of the cohort of larvae was: C = 39,150, A = 32,642, F = 6876, Pg = 13,052, Pev = 3608, Pr= 359-409 and R = 15,982 cal m- 2

As Caatingas formam um domínio morfoclimático exclusivo do Brasil, caracterizado por índices pluviométricos baixos e imprevisíveis, além de temperaturas elevadas. Em certos grupos de anuros, a sobrevivência durante o período de estiagem está associada ao comportamento de estivação, um conjunto de alterações observadas que permitem a sobrevivência em condições áridas. Os sapos Pleurodema diplolistris (Leiuperidae/Anura) são encontrados enterrados na Caatinga na fase de seca e evidências indicam que esses indivíduos apresentam menor atividade durante essa fase, apesar de exibirem certa migração vertical no substrato acompanhando a diminuição da umidade deste. O padrão de alterações nas concentrações de lipídeos e glicogênio em diferentes amostras de tecido corrobora a hipótese de diminuição do metabolismo durante o período de estiagem. No músculo dos membros posteriores, a manutenção dos níveis protéicos próximos aos valores observados em animais ativos coletados durante a fase de chuvas, sugere a preservação da capacidade funcional do tecido mesmo nos meses mais adversos. A capacidade aeróbia esteve reduzida durante a fase seca em comparação a fase de atividade e a capacidade glicolítica anaeróbia manteve-se preservada. Verificou-se também um gradiente de umidade vertical no abrigo, evidenciando uma diminuição da umidade a partir da superfície, ao longo da fase de estiagem, o que poderia corroborar a migração vertical. / Caatinga is a Brazilian semi-arid bioma that is characterized by the dryness and the unpredictable seasonality of rains. In some anurans the survive is associate with aestivation, a set of strategies for survival in arid conditions. Pleurodema diplolistris frogs (Leiuperidae/Anura) are found buried in the Caatinga during the dry time. Evidences indicate that individuals of this group have lower activity during this phase, although some exhibit vertical migration in the substrate following the decrease in the moisture of it. The pattern of changes in concentrations of lipids and glycogen in different samples of tissue supports the hypothesis of a reduction of metabolism during the drought. In the muscle of the hindquarters, the maintenance of protein levels close to those values observed in active animals collected during the rainy season, suggests the preservation of functional capacity of the tissue even in most adverse months. The aerobic capacity was reduced during the drought compared to the period of anaerobic glycolytic activity and the capacity has remained preserved. It was also found a gradient of moisture under the vertical, showing a decrease in moisture from the surface, during the drought, which could corroborate the vertical migration.

Life relies on the integration of external environmental stimuli and internal signals to balance fluctuations in nutrient availability to achieve homeostasis. Bone has recently emerged as a pleiotropic endocrine organ that secretes at least two hormones, FGF23 and osteocalcin, which regulate kidney function and glucose homeostasis, respectively. These findings have raised the question of whether other bone-derived hormones exist and what their potential functions are. Here we identify, through molecular and genetic analyses in mice, lipocalin 2 (LCN2) as an osteoblast-enriched, secreted protein. Loss- and gain-of-function experiments in mice demonstrate that osteoblast-derived LCN2 maintains glucose homeostasis by inducing insulin secretion and improves glucose tolerance and insulin sensitivity. In addition, osteoblast-derived LCN2 inhibits food intake. LCN2 crosses the blood–brain barrier, binds to the melanocortin 4 receptor (MC4R) in the paraventricular and ventromedial neurons of the hypothalamus and activates an MC4R-dependent anorexigenic (appetite-suppressing) pathway. These results identify LCN2 as a bone-derived hormone with metabolic regulatory effects, which suppresses appetite in a MC4R-dependent manner, and show that the control of appetite is an endocrine function of bone. Furthermore, we show that serum LCN2 levels correlate with insulin levels and β-cell function, indices of healthy glucose metabolism, in genetic and diet-induced mouse models of obesity and in obese, healthy or pre-diabetic patients. However, LCN2 serum levels also correlate with body mass index (BMI) and insulin resistance in the same patients; and are increased in obese mice. To dissect this apparent discrepancy, we examined LCN2 effects in hyperphagia and β -cell function mouse models of obesity or β -cell destruction. Silencing Lcn2 expression increases hyperphagia, fat and body weight and worsens β -cell function and general metabolic dysfunction in obese, leptin receptor-deficient mice. Conversely, LCN2 increases β-cell numbers and promotes β-cell function after streptozotocin-induced β -cell failure by (STZ) and acts as a growth factor necessary for β -cell adaptation to higher metabolic load in mice. These results support a protective role for LCN2 in obesity-induced glucose intolerance and insulin resistance that stem from its ability to decrease food intake and promote adaptive β-cell proliferation.

Some aspects of anuran metabolism are examined, with special emphasis on possible limitations to aerobic metabolism and the effect of chronic hypoxia acclimation on maximal rates of aerobic metabolism and the metabolic fate of lactic acid accumulated after anaerobic metabolism.

Abstract not available