RESUMO
The GH/IGF-I system plays a well-known hormonal role and its effects, mainly anabolic and insulin-sensitizing, are mediated through endocrine as well as paracrine/ autocrine mechanisms. This system includes the binding proteins, namely GH binding proteins and IGF-I binding proteins (IGFBP). As expected, this axis plays a key role in organism modification in consequence of a physical exercise. Physical activity, training, and exercise capacity chiefly involve anabolism process modifications of various tissues, in particular muscular adjustments. Numerous investigators found a correlation among the level of exercise tolerance, muscle strength or walking speed and IGF-I/IGFBP-3 concentrations. However, also inverse and absent correlations between circulating IGF-I concentrations and acute or chronic exercise responses have been reported. IGF-I is generally accepted as an important GH mediator with metabolic effects, through both endocrine and paracrine or autocrine mechanisms. GH is the main regulator of the hepatic synthesis of IGF-I and IGFBP-3, which is the most abundant IGF carrier in human plasma. Recently, it has been shown that the physical exercise stimulatory impact on skeletal muscles is mediated through an increased local IGF-I synthesis with an IGFPB involvement. An absent association of exercise performance and circulating IGF-I may indicate that exercise will exert muscle strength by predominately locally derived paracrine or autocrine mediators rather than endocrine circulating IGF-I. The present review considers the general aspects of the IGF/IGFPB system and the role of the IGF/IGFPB system in relation to physical exercise (type, duration, etc.) taking into account the training aspects.
Assuntos
Exercício Físico , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Músculo Esquelético/metabolismo , Dieta , Humanos , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/sangue , Fator de Crescimento Insulin-Like I/análise , Fígado/metabolismo , Isoformas de Proteínas/sangue , Isoformas de Proteínas/metabolismoRESUMO
Saliva contains cells and compounds, of local and non-local oral origin, namely inorganic, organic non-protein, protein/polypeptide, and lipid molecules. Moreover, some hormones, commonly assayed in plasma, such as steroids, are detectable in oral fluid and peptide/protein, and non-steroid hormones have been investigated. The sports practice environment and athletes' availability, together with hormone molecule characteristics in saliva and physical exercise behavior effects, confirm this body fluid as an alternative to serum. This review focuses on the relation between salivary steroids and psycho-physiological stress and underlines how the measurement of salivary cortisol provides an approach of self-report psychological indicator and anxiety change in relation to exercise performance. The correlation between salivary and plasma steroid hormone (cortisol, testosterone, and dehydroepiandrosterone (DHEA)) levels, observed during exercise, has been considered, underlining how the type, duration, and intensity of the exercise influence the salivary steroid concentrations in the same way as serum-level variations. Training conditions have been considered in relation to the salivary hormonal response. This review focuses on studies related to salivary hormone measurements, mainly steroids, in physical exercise. Saliva use in physical disciplines, as a real alternative to serum, could be a future perspective.
Assuntos
Exercício Físico/fisiologia , Hormônios/metabolismo , Saliva/metabolismo , Hormônios/fisiologia , Humanos , Esteroides/metabolismo , Esteroides/fisiologia , Estresse Fisiológico/fisiologia , Estresse Psicológico/metabolismo , Estresse Psicológico/fisiopatologiaRESUMO
BACKGROUND/AIMS: The offer of human saliva IGF-I (sIGF-I) measurement in athletes investigation is a new proposal. The aim was to investigate the physical exercise effect on sIGF-I and explore plasma free IGF-I relation. MATERIALS AND METHODS: Saliva and blood were collected from well-trained athletes, investigated immediately before and at the end of a physical exercise test. RESULTS: sIGF-I was significantly increased at the end of the physical exercise. The plasma free IGF-I concentrations did not demonstrate any difference. The saliva total protein level (sTP) was also significantly increased. A positive correlation between sTP and sIGF-I, was observed, both before and after physical exercise, and between salivary and plasma free IGF-I only after physical exercise. The salivary free IGF-I level significantly increased after physical exercise, moreover a correlation with the plasma levels exists in post-exercise condition. CONCLUSION: The physical exercise affects sIGF-I as well as the sTP. The correlation between plasma and salivary free IGF-I levels only in post-exercise condition suggests further studies to investigate the effects of different type and duration of physical exercise. The comparison with other salivary biochemical parameter investigation would also further increase comprehension on the role of salivary IGF-I.
Assuntos
Fator de Crescimento Insulin-Like I/metabolismo , Esforço Físico , Saliva/metabolismo , Adolescente , Ciclismo , Humanos , Masculino , Proteínas e Peptídeos Salivares/metabolismo , Adulto JovemRESUMO
AIM: The aim of this study was to investigate the urine cortisol (F) and cortisone (E) relation, having a well-defined water intake. METHODS: Urine specimens were collected from 10 male trained cyclists (19+/-1 year, 70+/-4 kg, 179+/-4 cm), at rest just before the test (pre-exe) and until 45 min after the cycle ergometer exercise test (45 min at 50-60% VO2max) (post-exe) in the morning. This investigation measured the diuresis in the pre-exe and post-exe after each athlete had drunk 1 L of water from waking-up, after bladder emptying, to the start of the test (pre-exe) and 1 L during the 45 min after the exercise (post-exe). RESULTS: Urinary F and E concentrations demonstrated a significant decrease comparing pre-exe with post-exe (177+/-134 vs 64+/-21 and 706+/-475 vs 372+/-178 nmol.L(-1) respectively, p < 0.05). This significant decrease was verified when diuresis and urinary creatinine were taken into account and the ratio measured. CONCLUSION: One litre of water intake after exercise seemed to have no effect on urine F and E excretion. Moreover the urine F/E ratio was not statistically different comparing pre-exe with post-exe.
Assuntos
Cortisona/urina , Comportamento de Ingestão de Líquido/fisiologia , Ingestão de Líquidos/fisiologia , Exercício Físico/fisiologia , Hidrocortisona/urina , Adulto , Antropometria , Creatinina/urina , Diurese , Ergometria , Teste de Esforço , Humanos , Masculino , Fatores de TempoRESUMO
OBJECTIVES: To examine an immunoassay for measuring free IGF-I in a saliva specimen (free sIGF-I) and to study the levels in relation to the training conditions comparing young athletes and sedentary females. DESIGN AND METHODS: The analysis was carried out by modifying a commercial kit for plasma matrix to measure the free sIGF-I. The plasma free and total IGF-I fractions, hGH and salivary total proteins were also measured. Saliva and blood specimens were collected from 15 well-trained young female volleyball athletes and from a control group of 14 young sedentary females. RESULTS: The calibration curve to assay free sIGF-I covered the range 0.05-5.00 microg/L. The detection limit was 0.07 microg/L. The within-run and between-run imprecision CVs were 10% and 13% respectively. The average recovery was 88%. Free sIGF-I, measured in 15 athletes and in 14 young sedentary females, was 0.10+/-0.03 and 0.20+/-0.05 micarog/L respectively (p<0.001). CONCLUSIONS: There were decreased levels of free sIGF-I in well-trained athletes, compared with sedentary females. This decrease could be related to a greater tissue requirement by the active muscle subjected to intense exercise for several days.
Assuntos
Exercício Físico/fisiologia , Fator de Crescimento Insulin-Like I/análise , Saliva/química , Proteínas e Peptídeos Salivares/análise , Adolescente , Adulto , Estudos de Casos e Controles , Feminino , Hormônio do Crescimento Humano/análise , Hormônio do Crescimento Humano/sangue , Humanos , Imunoensaio/métodos , Reprodutibilidade dos Testes , EsportesRESUMO
The circulating immunoreactive atrial natriuretic peptide (C-terminal; alpha-ANP) increases during exercise to become suppressed in the first hours of the recovery. The response of the N-terminal ANP fragments to acute exercise is not known while proANP (31-67) appears to be elevated with chronic exercise. We evaluated the plasma concentrations of the N-terminal ANP fragments (1-30) and (31-67) in oarsmen (n=10) before and after two acute exercise bouts separated by 5 h. As control, measurements were made on a day with no exercise (n=12). At rest, the concentrations of proANP(1-30) and proANP(31-67) were 344+/-42 and 810+/-172 pmol x l(-1), respectively. Half an hour after the first exercise bout, proANP(1-30) was elevated (to 404+/-48 pmol x l(-1); P<0.05) and decreased below the pre-exercise level (to 316+/-41 pmol x l(-1); P<0.05) 4 h into the recovery period. Also, 30 min after the second exercise session, the concentration of proANP(1-30) was elevated to 408+/-45 pmol x l(-1) (P<0.05) and the pre-exercise level was re-established on the following morning. Thus, proANP(1-30), rather than proANP(31-67), responded to acute exercise. These results suggest that atrial distension and, therefore, the central blood volume changes markedly in athletes during a day with repeated exercise bouts.
Assuntos
Fator Natriurético Atrial/sangue , Exercício Físico/fisiologia , Fragmentos de Peptídeos/sangue , Precursores de Proteínas/sangue , Adulto , Pressão Sanguínea/fisiologia , Estatura/fisiologia , Peso Corporal/fisiologia , Impedância Elétrica , Frequência Cardíaca/fisiologia , Humanos , Masculino , Tórax/metabolismo , Tórax/fisiologiaRESUMO
The importance of hormones on body metabolism when physical exercise is carried out has been established for a long time. Growth hormone (GH) is crucial in energy metabolism as well as in body anabolism. Recent studies have increased our knowledge of GH's mechanisms of action. In particular, insulin-like growth factor I (IGF-I), the main hormone mediating the principal GH effects and other protein structures (i.e. the binding proteins related to these two hormones), has been recognized as playing a crucial role. The biochemical aspects relating to the molecules of the GH/IGF-I axis have been described here. Furthermore, the belief that GH and IGF-I enhance performance has induced an 'abuse' of GH (and possibly of IGF-I) by competitive sports athletes and amateurs. The present study outlines the best methods available to uncover abuse, as well as a series of potential research projects to recognize doping. The review also underlines the principal variables measurable in the laboratory and summarizes published reference ranges of these parameters. These biochemical and laboratory profiles describe principal experimental approaches, with the hope that this will stimulate new ideas on the subject of detecting doping practices.
Assuntos
Dopagem Esportivo , Exercício Físico , Hormônio do Crescimento/administração & dosagem , Fator de Crescimento Insulin-Like I/administração & dosagem , Hormônio do Crescimento/metabolismo , Humanos , Fator de Crescimento Insulin-Like I/metabolismoRESUMO
The GH-related effects are primarily mediated by insulin-like growth factor I (IGF-I), a peptide hormone almost completely produced by the liver. Liver cirrhosis is usually accompanied by a fall in protein turnover. Furthermore, an important consequence of chronic liver disease (CLD) is growth hormone/insulin-like growth factor (GH/IGF) axis modification and growth failure. Nutritional status also suffers in this condition, and IGF-I has been proposed as a marker of hepatocellular dysfunction, malnutrition and survival. CLD is characterised by alterations of various clinical biochemistry laboratory parameters. Aminotransferases, bilirubin, plasma proteins, together with prothrombin time and gamma globulins, are usually examined for laboratory diagnostic and/or monitoring purposes. These traditional parameters are also used in the perioperative liver transplantation, but an early signal of graft functioning has still not been established. The aim of the present work is a review of the possibility offered by the clinical biochemistry laboratory GH/IGF investigation in the outcome of liver transplantation.
Assuntos
Hormônio do Crescimento/fisiologia , Cirrose Hepática/fisiopatologia , Cirrose Hepática/cirurgia , Transplante de Fígado , Somatomedinas/fisiologia , HumanosRESUMO
The family of the atrial natriuretic peptides, proANP fragments and the active alphaANP, is strongly related to heart disease. The aim was to study in CHF subjects the relation of mdANP and NtANP with brain natriuretic peptide (BNP) and with other traditional medical parameters. Sixteen CHF patients (aged 51.9+/-13.7 years) and 16 healthy subjects age matched (50.8+/-5.9 years) were selected. Both NtANP and mdANP were higher in CHF patients than in healthy subjects (1436+/-288 vs. 288+/-22 pmol/l p<0.001 and 2305+/-383 vs. 423+/-65 pmol/l p<0.0001, respectively). BNP in CHF patients was 28.0+/-9 pmol/l (reference values 1.7+/-1.8 pmol/l). Both NtANP and mdANP demonstrated positive correlation with BNP, p<0.0001 and with left atrial end-systolic volume, p<0.05. BNP correlated with left ventricular mass, p<0.03. In conclusion, plasma NtANP and mdANP analyses are useful laboratory markers in CHF patient investigation and follow up. In particular, they could be employed as non-invasive parameters to follow up worsening of systolic dysfunction until heart transplantation is required.
Assuntos
Fator Natriurético Atrial/sangue , Insuficiência Cardíaca/sangue , Transplante de Coração , Fragmentos de Peptídeos/sangue , Adulto , Fator Natriurético Atrial/química , Estudos de Casos e Controles , Humanos , Pessoa de Meia-IdadeRESUMO
BACKGROUND: ProANP(1-126), the prohormone synthesized and secreted by atrial myocites, generates an ANP peptide family, the main forms of which are proANP(1-30), proANP(31-67), proANP(1-98) and proANP(99-126). These molecular circulating forms are involved in hemodynamic and electrolyte homeostasis. In cirrhotic patients, volume homeostasis is almost impaired due to abnormal sodium retention, which results in ascites formation and hemodynamic changes, including high cardiac output and low systemic vascular resistance. During liver transplantation, in the anhepatic phase, hemodynamic instability may occur because of decreased venous return due to surgical manipulation of inferior vena cava, considerable blood loss or cross-clamping. Moreover, marked hemodynamic instability is often observed at the reperfusion of the graft. AIMS: The aims of present study are to investigate the changes of ANP during the perioperative phases of Orthotopic Liver Transplantation (OLTx) in end-stage cirrhotic patients. PATIENTS AND METHODS: From July to September 1999, 11 cirrhotic patients undergoing to OLTx were included in the study: seven males and four females (average age 46+/-10.4 years) affected by post-alcoholic cirrhosis [Hypertension 15 (1990) 9], post-hepatitis cirrhosis [D.G. Gardner, M.C. Lapointe, B. Kovacic-Milivojevic, C.F. Deschepper, Molecular analisys and regulation of the atrial natriuretic factor gene, in: A.D. Struphers (Ed.), Frontiers in Farmacology and Therapeutics: Atrial Natriuretic Factor, Blackwell, Oxford, England, 1991, pp. 1-22], Wilson disease [Life Sci. 28 (1981) 89] and polycystic disease [Life Sci. 28 (1981) 89], autoimmune cirrhosis [Life Sci. 28 (1981) 89]. In each patient, a hemodynamic assessment was achieved using a Swan-Ganz catheter. Periferical venous samples were performed during and immediately after OLTx for the determination of ANP(1-98) and other biohumoral parameters. RESULTS: Mean ANP(1-98) (pmol/ml mean+/-SD) basal levels resulted higher than that recorded in the group of healthy subjects. A significant correlation between 24-h post-reperfusion ANP and intra-operative RBC and RIS requirement was found (p<0.05). The basal values resulted significantly higher than that observed at phase II degrees (p<0.04) and lower than that at phase VI degrees (p<0.05); the anesthetic induction values were significantly lower than that observed at phase VI degrees (p<0.03). CONCLUSIONS: ANP(1-98) values may represent a useful marker of hemodynamic derangements during and after OLTx. Further clinical correlations will need a larger patient basis.
Assuntos
Fator Natriurético Atrial/sangue , Cirrose Hepática/cirurgia , Transplante de Fígado , Precursores de Proteínas/sangue , Adulto , Diurese , Feminino , Hematócrito , Hemodinâmica , Humanos , Cirrose Hepática/sangue , Cirrose Hepática/fisiopatologia , Masculino , Pessoa de Meia-Idade , Fragmentos de Peptídeos , Contagem de Plaquetas , Albumina Sérica/análise , Resultado do TratamentoAssuntos
Proteínas de Transporte/sangue , Hormônio do Crescimento/sangue , Cirrose Hepática/sangue , Transplante de Fígado/fisiologia , Alanina Transaminase/sangue , Aspartato Aminotransferases/sangue , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos ProspectivosRESUMO
Acyclovir (ACV) is an antiviral drug, which selectively inhibits replication of members of the herpes group of DNA viruses with low cell toxicity. Valaciclovir (VACV), a prodrug of ACV is usually preferred in the oral treatment of viral infections, mainly herpes simplex virus (HSV). Also other analogues such as ganciclovir and penciclovir are discussed here. The former acts against cytomegalovirus (CMV) in general and the latter against CMV retinitis. The action mechanism of these antiviral drugs is presented briefly here, mainly via phosphorylation and inhibition of the viral DNA polymerase. The therapeutic use and the pharmacokinetics are also outlined. The measurement of the concentration of acyclovir and related compounds in biological samples poses a particularly significant challenge because these drugs tend to be structurally similar to endogenous substances. The analysis requires the use of highly selective analytical techniques and chromatography methods are a first choice to determine drug content in pharmaceuticals and to measure them in body fluids. Chromatography can be considered the procedure of choice for the bio-analysis of this class of antiviral compounds, as this methodology is characterised by good specificity and accuracy and it is particularly useful when metabolites need to be monitored. Among chromatographic techniques, the reversed-phase (RP) HPLC is widely used for the analysis. C18 Silica columns from 7.5 to 30 cm in length are used, the separation is carried out mainly at room temperature and less than 10 min is sufficient for the analysis at 1.0-1.5 ml/min of flow-rate. The separation methods require an isocratic system, and various authors have proposed a variety of mobile phases. The detection requires absorbance or fluorescence measurements carried out at 250-254 nm and at lambdaex=260-285 nm, lambdaem=375-380 nm, respectively. The detection limit is about 0.3-10 ng/ml but the most important aspect is related to the sample treatment, mainly when body fluids are under examination. The plasma samples obtained from human blood are pre-treated with an acid or acetonitrile deproteinization and the supernatant after centrifugation is successively extracted before RP-HPLC injection. Capillary Electrophoresis methods are also discussed. This new analytical approach might be the expected evolution, in fact the analyses are improved with regard to time and performance, in particular coated capillary as well as addition of stabilisers have been employed. The time of analysis is shortened arriving at less than half a minute. Furthermore by using an electrochemical detection, and having a calibration linearity in the range of 0.2-20.0 ng/ml, the detection limit is 0.15 microg/ml. The measurements of acyclovir and penciclovir have been presented but in the future other related drugs will probably be available using CE methods.
Assuntos
Aciclovir/isolamento & purificação , Antivirais/isolamento & purificação , Aciclovir/farmacocinética , Aciclovir/farmacologia , Antivirais/farmacocinética , Antivirais/farmacologia , HumanosRESUMO
To examine the effects of acute branched-chainα-amino acids (BCAA) oral administration following chronic BCAA intake, a group of well trained young swimmers (n = 12) was submitted to a one month chronic BCAA treatment (0.2g/Kg body weight per die; Leu: Val: Ileu = 2:1:1) and a physical exercise test before and after this period of treatment was carried out. The exercise tests (60min swim) were performed in a high circulating BCAA level state which was obtained through oral BCAA administration (or placebo) just before the beginning of the exercise. The groups will be referred to as BCAA/before, BCAA/after, placebo/before, placebo/after. Blood and plasma (antecubital vein) samples were collected from the different groups at different times: on the morning of the day before the test (basal time, rest 0), the following day 30min after an acute administration (oral dose placebo or BCAA acute treatment: Leu 4.8g, Val 2.4g, Ileu 2.4g), just before the beginning of the exercise performance (time 0min, rest 1), at the end of the exercise (time 60min, EE) and during recovery (time 120min, Re). Plasma ammonia levels increased significantly from rest 1 to the end of the exercise in all subjects, but it was significantly higher in BCAA treated than in placebo subjects in both the before and after chronic treatment groups (BCAA/before: from 38 ± 7 to 204 ± 65mmol/l; placebo/before: from 36 ± 10 to 93 ± 29mmol/l; BCAA/after: from 36 ± 9 to 171 ± 43mmol/l; placebo/after: from 30 ± 6 to 65 ± 16mmol/l). Plasma ammonia level increments observed before a chronic one month BCAA treatment were significantly higher than after this treatment (p < 0.05). Plasma alanine was at all times of the test higher before the BCAA chronic treatment than after; this difference resulted significant at rest 0, rest 1 and recovery times (p < 0.05). After acute BCAA administration, plasma BCAA levels increased from 618 ± 52mmol/l to 1893 ± 284mmol/l (p < 0.05) from the onset of exercise and remained elevated throughout the test. Placebo and basal (rest 0) levels both before and after the chronic treatment did not demonstrate any significant differences. Plasma BCAA and BCKA levels, in the BCAA/before demonstrated significantly higher levels than placebo/before at rest 1 time (BCAA/before vs placebo/before: Leu 86 ± 27 vs 620 ± 97mmol/l; KIC 60 ± 3 vs 87 ± 5mmol/l, Ileu 51 ± 19 vs 359 ± 56mmol/l, KMV 26 ± 1 vs 43 ± 2mmol/l, Val 290 ± 79 vs 915 ± 133mmol/l, KIV 14 ± 1 vs 24 ± 2mmol/l). The levels after the chronic treatment maintained circa these differences in the two groups BCAA/after and placebo/after. The plasma BCAA as well as the BCKA levels of acutely treated athletes, in physical exercise, showed a different profile before and after the chronic treatment. The chronic treated BCAA/after group in fact depicted a decreasing BCKA level profile at the end of the exercise and during recovery; on the contrary, before the chronic treatments, acutely treated athletes demonstrated a tendency to increase these levels during recovery. These data seem to confirm that increased BCAA availability, before exercise, result in significantly greater plasma ammonia responses during exercise than does placebo administration; furthermore this increment is lower after chronic treatment. The interpretation of the ammonia data is difficult since the exercise type could have an influence on this phenomenon. The differences in the profile patterns of alanine, BCAA and BCKA levels seem to indicate that the chronic treatment brings about a state in which there is a better use of BCAA compounds as energy supply.
RESUMO
The purpose of the present study was to investigate the relationship between plasma carnitine concentration and body composition variation in relation to muscular and fat masses since there is no experimentally proved correlation between plasma carnitine and body masses. We used bioelectric impedance analysis (BIA), to determine body composition and to have a complete physical fitness evaluation. The post-absorptive plasma free carnitine and acetyl carnitine plasma levels, body composition as Fat-Free Mass (FFM) and Fat Mass (FM) in kg, as well as in percent of body mass, were analysed in 33 healthy subjects. A significant negative correlation was found between plasma acetyl carnitine and FFM in weight (kg) as well as in percent of body mass (respectively p < 0.0001; p < 0.01); a significant positive correlation was found only between FM in percent and plasma acetyl carnitine (p < 0.01). The observed negative correlation between plasma acetyl carnitine and muscular mass variation might reflect an oxidative metabolic muscle improvement in relation to muscular fat free mass increment and might be evidence that muscle metabolism change is in relation to plasma acetyl carnitine concentration.
Assuntos
Acetilcarnitina/sangue , Carnitina/sangue , Músculos/anatomia & histologia , Aptidão Física/fisiologia , Adolescente , Adulto , Composição Corporal , Índice de Massa Corporal , Impedância Elétrica , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
In relation to energy request during physical exercise, muscular tissue Branched Chain Amino Acids (BCAA) are metabolized particularly when the oxidation rises. But in the whole-human body, it is difficult to estimate, in a quantitative sense, the role played by BCAA in sustaining exercise. During a BCAA treatment, made on a group of athletes kept under observation, it was observed, through Conconi's test, that this treatment influenced physical performance. Aim of present work is to investigate if BCAA chronic treatment effect on physiological trial is confirmed on blood circulating biochemical energy parameters and in particular on acetyl-carnitine, since acetyl-linked compounds may be an important biochemical factor.Fourteen athletic well trained male subjects, were randomly divided into two subgroups; a first group was submitted to a chronic treatment (n = 7) of BCAA (oral intake was 0.2 g/Kg die) and a second group, as controls (n = 7), assumed oral placebo. Conconi's test demonstrated a significant difference (p < 0.005) in the exercise performance of the two sub-groups, comparing the measurements of ratios of deflection velocity (V d ), before and after the treatment. Therefore we studied the athletes performing a muscular exercise test (40 Km/h, cycle race, for 90 min) after one month of treatment. During this treatment period the subjects followed a well standardized diet. Samples of blood were drawn before, at the end and during the recovery (60 min) to study if traditional biochemical parameters varied and confirmed the observed differences in Conconi's test. The measurements of concentrations of FFA, KB, free carnitine, acetyl-carnitine and BCAA were performed. Plasma BCAA levels did not demonstrate variations either before or after the exercise performance, or between the two groups. The biochemical factors, substrates and hormones, KB, FFA, lactate, insulin and growth hormone plasma levels did not demonstrate significant differences from the patterns present in literature. Plasma free and acetyl-carnitine followed the well known variations, but only acetyl-carnitine levels demonstrated, at the end increase in acetyl-carnitine levels could be related to a minor fatigue situation and to a larger energy supply availability perhaps present in BCAA treated athletes (Sahlin et al., 1990; May et al., 1989). Both mentioned hypothesis seem in concordance with a smaller acetyl-CoA substrate accumulation, or better for present study, is even more successful with athletes who give a better physical performance. In fact Conconi's test in the two sub-groups of athletes seems to suggest that BCAA treated athletes were able to give a better performance, furthermore out of curiosity we point out that the athletes treated with BCAA won more races than the untreated.We would also like to add in conclusion that although confirming the difficulties of studies in the whole-body, our work gives an interesting clue about the possibility to use acetyl-carnitine plasma levels to understand the biochemical importance of the BCAA as substrate able to influence physical performance, but further research is needed.The phenomenon presence might be showed better perhaps by studying untrained groups during prolonged exercise and with physical performance at exhaustion. If treatment were able to help the physical performance and to shift the fatigue, then confirmation might be a less raised plasma acetyl-carnitine level. In effect blood ammonium levels in present study did not demonstrate any variation in and between sub-groups; this latter observation could be caused by the quantity of work load, and training state of the athletes (Ji et al., 1987; Kirkendall, 1990). Moreover, as observed by Hageloch et al. (1990), the ammonia increases less during prolonged endurance exercise, and in fact the athletes of present study were all middle distance racing cyclists, and the physical performance was a prolonged endurance exercise.
RESUMO
Branched chain amino acids (BCAA) stimulate protein synthesis, and growth hormone (GH) is a mediator in this process. A pre-exercise BCAA ingestion increases muscle BCAA uptake and use. Therefore after one month of chronic BCAA treatment (0.2 gkg(-1) of body weight), the effects of a pre-exercise oral supplementation of BCAA (9.64 g) on the plasma lactate (La) were examined in triathletes, before and after 60 min of physical exercise (75% of VO2 max). The plasma levels of GH (pGH) and of growth hormone binding protein (pGHBP) were also studied. The end-exercise La of each athlete was higher than basal. Furthermore, after the chronic BCAA treatment, these end-exercise levels were lower than before this treatment (8.6+/-0.8 mmol L(-1) after vs 12.8+/-1.0 mmol L(-1) before treatment; p < 0.05 [mean +/- std. err.]). The end-exercise pGH of each athlete was higher than basal (p < 0.05). Furthermore, after the chronic treatment, this end-exercise pGH was higher (but not significantly, p = 0.08) than before this treatment (12.2+/-2.0 ng mL(-1) before vs 33.8+/-13.6 ngmL(-1) after treatment). The end-exercise pGHBP was higher than basal (p < 0.05); and after the BCAA chronic treatment, this end-exercise pGHBP was 738+/-85 pmol L(-1) before vs 1691+/-555 pmol L(-1) after. pGH/pGHBP ratio was unchanged in each athlete and between the groups, but a tendency to increase was observed at end-exercise. The lower La at the end of an intense muscular exercise may reflect an improvement of BCAA use, due to the BCAA chronic treatment. The chronic BCAA effects on pGH and pGHBP might suggest an improvement of muscle activity through protein synthesis.
Assuntos
Aminoácidos de Cadeia Ramificada/farmacologia , Proteínas de Transporte/sangue , Exercício Físico , Hormônio do Crescimento Humano/sangue , Ácido Láctico/sangue , Adulto , Aminoácidos de Cadeia Ramificada/farmacocinética , Peso Corporal/efeitos dos fármacos , Suplementos Nutricionais , Humanos , Ácido Láctico/metabolismo , Masculino , Pessoa de Meia-Idade , Corrida , Natação , Fatores de TempoRESUMO
BACKGROUND: Atrial natriuretic peptide (ANP) is synthesized and stored in myocytes as prohormone(1-126), which upon release is cleaved into proANP(1-98) and alpha-ANP(99-126). In addition, cleavage of proANP(1-98) produces proANP(1-30), proANP(31-67), and proANP(79-98) fragments. ProANP(1-30) and proANP(31-67) have roles in fluid and electrolyte homeostasis. The aim of the present study was to develop a plasma assay for proANP(1-30) and proANP(31-67) and to compare results in trained athletes and sedentary subjects. METHODS: Two competitive enzyme immunoassays were established with affinity-purified sheep antiserum against synthetic ANP fragments. The immunoreactivity (ir) of proANP(1-30) and proANP(31-67) was measured in 10-microL plasma samples without extraction in a microwell-based assay. Plasma concentrations in sedentary male subjects (n = 22) and male endurance athletes (n = 14) were examined. RESULTS: In the assay for ir-proANP(1-30) and ir-proANP(31-67), the concentrations at 95% B/B(0) were 4.7 and 14.2 pmol/L, respectively. Within-run CVs were 4-6% and 5-6%, and between-run CVs were 9% for both assays. Both assays were linear on dilution (y = 0.9945x - 0. 7291 and y = 1.0001x - 3.428), and the recoveries were 102-112% and 102-106%, respectively. In the sedentary and athletic groups, the ir-proANP(1-30) concentrations were similar: 318 +/- 38 pmol/L and 312 +/- 25 pmol/L (mean +/- SE), respectively, whereas the ir-proANP(31-67) was higher in the rowers (713 +/- 81 pmol/L) than in the sedentary subjects (387 +/- 71 pmol/L; P <0.005). CONCLUSIONS: The proANP fragment assays are precise (CV <10%) and exhibit nearly quantitative recovery (102-112%). Only ir-proANP(31-67) responds to physical training.
Assuntos
Fator Natriurético Atrial/sangue , Fragmentos de Peptídeos/sangue , Precursores de Proteínas/sangue , Esportes , Animais , Fator Natriurético Atrial/química , Circulação Sanguínea , Reações Cruzadas , Humanos , Soros Imunes , Técnicas Imunoenzimáticas , Masculino , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/imunologia , Precursores de Proteínas/química , Sensibilidade e Especificidade , OvinosRESUMO
Using capillary zone electrophoresis, the urine creatinine (uCr) assay was validated in extemporaneous diluted urine, both in healthy subjects and athletes, with the uCr concentration as a reference value to compare excretion rates of other metabolites in the same samples. The electrokinetic sample injection was carried out at 10 kV per 10 s; UV absorbance detection was at 254 nm. Using standard samples, the creatinine migration mean time in 100 mmol/L acetate buffer, pH 4.4, was 3.3+/-0.2 min; the repeatability for absolute migration mean time was 0.6% and peak height repeatability was 2.9%. The correlation coefficient of the standard curve was r = 0.999 and the detection limit was 23.1 micromol/L. Intra- and interassay coefficients of variation (CV) were 3.0 and 3.6%, respectively; recovery was 99+/-3% and linearity was r= 0.98. Normal urine samples were diluted 1:80 in run buffer. The present CE urine creatinine assay showed a good correlation with HPLC and with Jaffe methods (r = 0.98 and r = 0.97, respectively; p < 0.0001). The uCr in the morning urine samples of 34 healthy males (M), 38 healthy females (F), and 83 male athletes (A) was 10.4+/-6.1 mmol/L, 10.8+/-8.1 mmol/L and 13.2+/-6.5 mmol/L, respectively. The uCr difference (p < 0.02) between M and A and a correlation (p < 0.05) with age in A were observed.