RESUMO
The purpose of this study was to examine salivary cortisol, dehydroepiandrosterone (DHEA), and testosterone responses to the bench press in an international powerlifting competition and to determine whether these salivary hormone concentrations could be used to predict performance. Twenty-six elite athletes (13 females and 13 males) provided saliva samples during the official weighing-in and after the last attempt at the bench press, as well as at baseline on a non-competition day. Performance index was determined with the Wilks formula, which adjusts powerlifting scores according to body mass. Salivary cortisol concentrations were significantly increased in all subjects after the bench press (p < 0.01), whereas DHEA concentrations were significantly increased in women (p < 0.01) but not in men after the bench press. No significant change in testosterone concentrations was observed during the experiment in either men or women, which resulted in a marked decrease in the testosterone/cortisol ratio. The performance index showed no significant correlation with any of the hormone responses to competition. In conclusion, despite the increase in stress adrenocortical hormone responses to an international powerlifting competition, these hormone concentrations alone are not predictors of bench press performance in elite powerlifting athletes.
Assuntos
Desidroepiandrosterona/metabolismo , Hidrocortisona/metabolismo , Saliva/metabolismo , Testosterona/metabolismo , Levantamento de Peso/fisiologia , Adulto , Feminino , Humanos , Sistema Hipotálamo-Hipofisário/fisiologia , Masculino , Sistema Hipófise-Suprarrenal/fisiologiaRESUMO
BACKGROUND: Given the high correlation between the serum and saliva hormone values demonstrated at rest, saliva provides a convenient non-invasive way to determine dehydroepiandrosterone (DHEA) and cortisol concentrations. However, to our knowledge, pituitary adrenal recovery following short-term suppression with corticosteroids has never been investigated in saliva. The aim of this study was therefore to examine how steroid hormone concentrations in saliva are influenced by short-term corticosteroid administration. MATERIALS AND METHODS: We studied saliva DHEA and cortisol concentrations before, during (day 1-day 7) and following (day 8-day 16) the administration of oral therapeutic doses of prednisone (50 mg daily for 1 week) in 11 healthy recreationally trained women. RESULTS: Mean saliva DHEA and cortisol concentrations decreased immediately after the start of prednisone treatment (P < 0.05). Three days after concluding prednisone administration, both saliva DHEA and cortisol had returned to pretreatment levels. CONCLUSIONS: These data are consistent with previous studies on blood samples and suggest that non-invasive saliva samples may offer a practical approach to assessing pituitary-adrenal function continuously during and after short-term corticosteroid therapy.
Assuntos
Desidroepiandrosterona/metabolismo , Glucocorticoides/administração & dosagem , Hidrocortisona/metabolismo , Prednisona/administração & dosagem , Saliva/metabolismo , Adulto , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Adulto JovemRESUMO
In order to test the hypothesis that salbutamol would change substrate oxidation during submaximal exercise, eight recreationally trained men twice performed 1 h at 60% VO(2) peak after ingestion of placebo or 4 mg of salbutamol. Gas exchange was monitored and blood samples were collected during exercise for GH, ACTH, insulin, and blood glucose and lactate determination. With salbutamol versus placebo, there was no significant difference in total energy expenditure and substrate oxidation, but the substrate oxidation balance was significantly modified after 40 min of exercise. ACTH was significantly decreased with salbutamol during the last 10 min of exercise, whereas no difference was found between the two treatments in the other hormonal and metabolic parameters. The theory that the ergogenic effect of salbutamol results from a change in substrate oxidation has little support during relatively short term endurance exercise, but it is conceivable that longer exercise duration can generate positive findings.
Assuntos
Albuterol/farmacologia , Oxirredução/efeitos dos fármacos , Resistência Física/efeitos dos fármacos , Resistência Física/fisiologia , Hormônio Adrenocorticotrópico/sangue , Glicemia , Exercício Físico/fisiologia , Hormônio do Crescimento/sangue , Humanos , Insulina/sangue , Ácido Láctico/sangue , Masculino , Esforço Físico/efeitos dos fármacos , Esforço Físico/fisiologia , Fatores de Tempo , Adulto JovemRESUMO
In order to test the hypothesis that short-term corticoid intake alters food intake, body composition and adipokines secretion in healthy volunteers with regular sport practice, nutrient intake was assessed in eight male athletes with and without prednisolone (PRED, 60 mg/day for 1 week) ingestion in a random, double blind, crossover design. Body weight, body composition, adipokines (i.e., leptin, adiponectin and TNF-alpha), insulin and blood glucose were determined before and at the end of each treatment. PRED did not induce any significant change in body weight, body composition or food intake. Insulin and TNF-alpha were not significantly altered with PRED compared to placebo but blood glucose, leptin and adiponectin concentrations at rest appear significantly increased after PRED treatment (P < 0.05). Our data show that 1 week glucocorticoid treatment does not promote obesity in recreationally trained men but further studies are necessary to understand its effects on the metabolically active hormones, leptin and adiponectin.
Assuntos
Adiponectina/sangue , Ingestão de Alimentos/efeitos dos fármacos , Leptina/sangue , Prednisolona/farmacologia , Fator de Necrose Tumoral alfa/sangue , Glicemia , Composição Corporal/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Humanos , Insulina/sangue , Masculino , Distribuição Aleatória , Adulto JovemRESUMO
Metabolites of hydrocortisone (HC) and cortisone (C), namely tetrahydrocortisol (THF), tetrahydrocortisone (THE), allo-THF, allo-THE for the main metabolites and 11-hydroxyandrosterone, 11-hydoxyetiocholanolone, 11-ketoandrosterone, and 11-ketoetiocholanolone for the minor metabolites, as well as the two main metabolites of testosterone, androsterone and etiocholanolone, were separated from each other using HPLC fractionation of urine extracts. An isotopic ratio mass spectrometry (IRMS) analysis determined the absolute delta(13)C values of 5alpha-androstanetrione (5alpha-AT) and 5beta-androstanetrione (5beta-AT) as the oxidation products (ox-products) of the HC and C metabolites and as target compounds (TCs). We also performed IRMS analysis of 5alpha-androstanedione (5alpha-AD) and 5beta-androstanedione (5beta-AD) as the ox-products of etiocholanolone and androsterone and as endogenous reference compounds (ERCs). Urine samples came from two male volunteers treated with a single 10-mg oral dose and a single 100-mg intramuscular dose of HC hemisuccinate, a male volunteer treated with a single 25-mg oral dose of C acetate, and a control group of 30 drug-free athletes. The mean -3SD of delta(13)C depletion values from the controls were -1.46, -1.98, -1.78 and -2.42 for 5beta-AT-5beta-AD, 5alpha-AT-5beta-AD, 5beta-AT-5alpha-AD and 5alpha-AT-5alpha-AD, respectively, indicating -3 per thousand as a safe cut-off value for differentiating the pharmaceutical from the natural form. In the main metabolite fraction, delta(13)C depletion values peaked around -5 per thousand and -9 per thousand after oral and intramuscular administration of HC, respectively, and around -6 per thousand after oral administration of C. In comparison, less impressive results were obtained when IRMS analysis focused on the ox-products of the minor metabolites.
Assuntos
Cortisona/urina , Dopagem Esportivo , Hidrocortisona/urina , Isótopos/análise , Espectrometria de Massas/métodos , Cortisona/metabolismo , Hidrocortisona/metabolismoRESUMO
OBJECTIVE: To examine whether acute glucocorticoid (GC) intake alters performance and selected hormonal and metabolic variables during submaximal exercise. METHODS: In total, 14 recreational male athletes completed two cycling trials at 70-75% maximum O(2) uptake starting 3 h after an ingestion of either a lactose placebo or oral GC (20 mg of prednisolone) and continuing until exhaustion, according to a double-blind randomised protocol. Blood samples were collected at rest, after 10, 20, 30 minutes, and at exhaustion and recovery for measurement of growth hormone (GH), adrenocorticotropic hormone (ACTH), dehydroepiandrosterone (DHEA), prolactin, insulin, blood glucose, lactate and interleukin (IL)-6 determination. RESULTS: Cycling duration was not significantly changed after GC or placebo administration (55.9 (5.2) v 48.8 (2.9) minutes, respectively). A decrease in ACTH and DHEA (p<0.01) was observed with GC during all of the experiments and in IL-6 after exhaustion (p<0.05). No change in basal, exercise or recovery GH, prolactin, insulin or lactate was found between the two treatments but blood glucose was significantly higher with GC (p<0.05) at any time point. CONCLUSION: From these data, acute systemic GC administration does seem to alter some metabolic markers but did not influence performance during submaximal exercise.
Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Metabolismo Energético/efeitos dos fármacos , Glucocorticoides/farmacologia , Resistência Física/efeitos dos fármacos , Prednisolona/farmacologia , Adulto , Método Duplo-Cego , Metabolismo Energético/fisiologia , Exercício Físico/fisiologia , Glucocorticoides/administração & dosagem , Humanos , Masculino , Resistência Física/fisiologia , Esforço Físico/efeitos dos fármacos , Esforço Físico/fisiologia , Prednisolona/administração & dosagemRESUMO
OBJECTIVE: To investigate the effects of short-term prednisolone ingestion combined with intense training on exercise performance, hormonal (adrenocorticotrophic hormone (ACTH), prolactin, luteinising hormone (LH), growth hormone (GH), thyroid-stimulating hormone (TSH), dehydroepiandrosterone (DHEA), testosterone, insulin) and metabolic parameters (blood glucose, lactate, bicarbonate, pH). METHODS: Eight male recreational athletes completed four cycling trials at 70-75% peak O(2) consumption until exhaustion just before (1) and after (2) either oral placebo or prednisolone (60 mg/day for 1 week) treatment coupled with standardised physical training (2 hours/day), according to a double-blind and randomised protocol. Blood samples were collected at rest, during exercise and passive recovery for the hormonal and metabolic determinations. RESULTS: Time of cycling was not significantly changed after placebo but significantly increased (p<0.05) after prednisolone administration (50.4 (6.2) min for placebo 1, 64.0 (9.1) min for placebo 2, 56.1 (9.1) min for prednisolone 1 and 107.0 (20.7) min for prednisolone 2). There was no significant difference in any measured parameters after the week of training with placebo but a decrease in ACTH, DHEA, PRL, GH, TSH and testosterone was seen with prednisolone treatment during the experiment (p<0.05). No significant change in basal, exercise or recovery LH, insulin, lactate, pH or bicarbonate was found between the two treatment, but blood glucose was significantly higher under prednisolone (p<0.05) at all time points. CONCLUSION: Short-term glucocorticoid administration induced a marked improvement in endurance performance. Further studies are needed to determine whether these results obtained in recreational male athletes maintaining a rigorous training schedule are gender-dependent and applicable to elite athletes.
Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Glucocorticoides/farmacologia , Hormônios/metabolismo , Prednisolona/farmacologia , Glicemia/metabolismo , Estudos Cross-Over , Método Duplo-Cego , Humanos , Masculino , Consumo de Oxigênio/efeitos dos fármacos , Consumo de Oxigênio/fisiologia , Fatores de Tempo , Adulto JovemRESUMO
We examined the hypothesis that acute therapeutic glucocorticoid intake could change the contribution of fat and carbohydrate (CHO) in energy production during exercise. Nine healthy recreationally-trained male subjects twice performed submaximal exercise (60 min at 60 % VO2max) after ingestion of placebo (Pla) or 20 mg of prednisolone (Pred), according to a double blind and randomized protocol. Respiratory exchange was monitored during exercise and blood samples were collected at rest, every 10 min during exercise and after 5, 10, and 20 min of passive recovery. Pred intake significantly increased total energy expenditure during exercise, but CHO oxidation was lower and fat oxidation higher after Pred vs. Pla. ACTH and IL-6 concentrations were significantly decreased with Pred during exercise, whereas no variations were found in GH, insulin, blood glucose, and lactate between the 2 treatments. In conclusion, it appears that acute prednisolone systemic administration does reduce total carbohydrate oxidation during submaximal exercise. Further studies are necessary to clarify the mechanisms involved and to determine whether this modification in the substrate oxidation balance under glucocorticoid administration in recreationally-trained male subjects could result in a competitive advantage in elite athletes.
Assuntos
Metabolismo Energético/efeitos dos fármacos , Exercício Físico/fisiologia , Glucocorticoides/farmacologia , Prednisolona/farmacologia , Hormônio Adrenocorticotrópico/sangue , Hormônio Adrenocorticotrópico/efeitos dos fármacos , Adulto , Glicemia/efeitos dos fármacos , Metabolismo dos Carboidratos/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Gorduras/metabolismo , Hormônio do Crescimento/sangue , Humanos , Insulina/sangue , Interleucina-6/sangue , Ácido Láctico/sangue , Masculino , Pessoa de Meia-Idade , OxirreduçãoRESUMO
To study the effects of a therapeutical dose of corticosteroid alone or associated with beta-2 agonist on performance and substrate response during intense submaximal exercise, seven healthy moderately trained male volunteers participated in the double-blind randomized cross-over study. An intense endurance exercise test to exhaustion was performed after ingestion of placebo (Pla), 20 mg prednisolone (Pred), and 20 mg prednisolone plus 4 mg salbutamol (Pred-Sal). Blood samples were collected at rest, after 5, 10 min of exercise, at exhaustion, and after 5 (r5), 10 (r10), and 20 (r20) min of passive recovery for ACTH, growth hormone, insulin, blood glucose, and lactate measurements. There were no significant differences in exercise time to exhaustion between the three treatments (Pla: 21.5 +/- 2.9; Pred: 22.0 +/- 2.5; Pred-Sal: 24.2 +/- 2.8 min). ACTH was significantly lowered after Pred and Pred-Sal vs. Pla from the start of exercise to the end of the experiment (p < 0.05). Pred and Pred-Sal increased resting and recovery (r10 and r20) significantly but not exercise blood glucose values. There were no significant differences in growth hormone concentrations between the three treatments whereas insulin was significantly higher at rest, during exercise, and at r20 after Pred-Sal administration vs. Pred and Pla (p < 0.05). Pred and Pred-Sal showed no significant effect on blood lactate compared with Pla treatment. These preliminary results do not support the hypothesis that acute oral therapeutic corticosteroid intake alone or associated with beta-2 mimetic improves performance during intense submaximal exercise, but further studies are necessary with tests of longer duration.
Assuntos
Agonistas Adrenérgicos beta/farmacologia , Albuterol/farmacologia , Exercício Físico/fisiologia , Glucocorticoides/farmacologia , Prednisolona/farmacologia , Hormônio Adrenocorticotrópico/sangue , Adulto , Glicemia/metabolismo , Método Duplo-Cego , Interações Medicamentosas , Hormônio do Crescimento/sangue , Humanos , Insulina/sangue , Ácido Láctico/sangue , MasculinoRESUMO
OBJECTIVE: To test the hypothesis that chronic salbutamol intake improves performance during supramaximal exercise and to estimate the effects of this treatment on body composition, bone mass, and metabolic indices in healthy women. METHODS: Fourteen female volunteers (seven sedentary and seven recreationally trained) performed a 30 second Wingate test with and without salbutamol ingestion (12 mg/day for four weeks) in a random, double blind, crossover design. Blood samples were collected at rest, at the end of the test, and during passive recovery for lactate measurement. Body composition and bone mass were determined by dual energy x ray absorptiometry. RESULTS: Peak power appeared significantly earlier and was significantly (p<0.05) increased after salbutamol intake in all subjects. There was no difference in total work performed and fatigue indices with salbutamol compared with placebo. No significant alterations in lean or fat body mass and bone variables were observed with salbutamol treatment in either trained or untrained subjects during the trial. In contrast, blood lactate was significantly (p<0.05) increased during the recovery period after salbutamol ingestion compared with placebo. CONCLUSION: As in men, chronic administration of therapeutic concentrations of salbutamol did not induce an anabolic effect in women but increased maximal anaerobic power. Further studies are necessary to clarify the mechanisms involved.
Assuntos
Agonistas Adrenérgicos beta/administração & dosagem , Albuterol/administração & dosagem , Exercício Físico/fisiologia , Adulto , Limiar Anaeróbio/efeitos dos fármacos , Composição Corporal/efeitos dos fármacos , Índice de Massa Corporal , Densidade Óssea/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Teste de Esforço/métodos , Feminino , Humanos , Ácido Láctico/sangueRESUMO
To investigate the impact of acute salbutamol intake on performance and selected hormonal and metabolic variables during supramaximal exercise, 13 recreational male athletes performed two 30-second Wingate tests after either placebo (PLA, lactose) or salbutamol (SAL, 4 mg) oral administration, according to a double-blind and randomized protocol. Blood samples collected at rest, end of the Wingate test, recovery (5, 10, 15 min) were tested for growth hormone (GH), insulin (INS), blood glucose (GLU), and lactate determination. We found the peak and mean power performed significantly increased after SAL vs. PLA (PPSAL: 896 +/- 46; PPPLA: 819 +/- 57 W; MPSAL: 585 +/- 27; MPPLA: 534 +/- 35 W, p < 0.05), whereas no change was observed in the fatigue index. Blood glucose and INS were significantly increased by SAL at rest, at the end of the Wingate test, and during the 5 first minutes of recovery (p < 0.05). Plasma GH was significantly decreased by SAL (p < 0.05) during the recovery whereas end-exercise and recovery blood lactate tended but were not significantly increased after SAL vs. PLA. From these data, acute salbutamol intake at therapeutical dosage did appear to improve peak power and mean power during a supramaximal exercise, but the mechanisms involved need further investigation.
Assuntos
Agonistas Adrenérgicos beta/administração & dosagem , Albuterol/administração & dosagem , Teste de Esforço/efeitos dos fármacos , Exercício Físico/fisiologia , Administração Oral , Adulto , Limiar Anaeróbio/efeitos dos fármacos , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Relação Dose-Resposta a Droga , Método Duplo-Cego , Hormônio do Crescimento Humano/sangue , Humanos , Insulina/sangue , Ácido Láctico/sangue , Masculino , Descanso/fisiologia , Levantamento de Peso/fisiologiaRESUMO
The effects of a chronic salbutamol intake (SAL, 12 mg/d during 3 weeks) on changes in body composition, metabolic indices and performance during a 30-second Wingate test were determined in 8 strength-trained male athletes (T) and 7 sedentary male (UT) subjects, according to a double-blind, randomized, cross-over protocol. Blood samples were collected both at rest, at the end of the test, and during passive recovery (5 min, 10 min, 15 min) for leptin (at rest), and blood lactate measurements. No significant changes in lean body mass, fat mass, and leptin were observed with SAL treatment in either group during the trial. Peak power was significantly increased (p < 0.05) after SAL intake in all subjects (T: 11.9 %; UT: 8.3 %) with a decrease in time to peak power with SAL compared to placebo (PLA) (p < 0.05). There was no change in total work performed and in fatigue indices with SAL compared to PLA. Blood lactate was significantly increased after SAL vs. PLA during the recovery (p < 0.05) in all subjects. The data demonstrate that the chronic administration of therapeutic levels of salbutamol increases maximal anaerobic power in man, irrespective of the subjects' training status. This study also rules out any implication of an anabolic effect in this improvement in performance during supramaximal exercise. Further studies are necessary to clarify the mechanisms involved.
Assuntos
Agonistas Adrenérgicos beta/administração & dosagem , Albuterol/administração & dosagem , Teste de Esforço/efeitos dos fármacos , Exercício Físico/fisiologia , Administração Oral , Adulto , Composição Corporal/efeitos dos fármacos , Composição Corporal/fisiologia , Estudos Cross-Over , Relação Dose-Resposta a Droga , Método Duplo-Cego , Humanos , Ácido Láctico/sangue , Leptina/sangue , Masculino , Descanso/fisiologia , Levantamento de Peso/fisiologiaRESUMO
AIM: The aim of the study was to test the accuracy of 2 versions of a specific soccer field test for assessing maximal aerobic velocity (MAV) in soccer players. The original Probst field test consists of repetitions of 280 m runs including changes in direction separated by a 30-second rest with an initial speed of 8.4 km x h(-1) and a 0.6 km x h(-1) increment at each stage. The adapted version was carried out with the same protocol but constant stages of 2-minute durations and a 1.2 km x h(-1) increment at each stage. METHODS: Trained soccer players completed 4 outdoor field tests: the original and adapted field Probst tests, both with and without changes in direction, in order to determine the velocities at exhaustion. They all underwent at the same time 3 laboratory tests in order to determine MAV during a classical graded treadmill test, a laboratory test with the same stages as the original Probst test and the adapted Probst test. RESULTS: The velocities at exhaustion with and without changes in direction obtained during the adapted Probst field test, and the MAV obtained in the laboratory were highly correlated. All were significantly lower than the velocities at exhaustion obtained during the original version. CONCLUSIONS: The adapted version was a better predictor of MAV in trained soccer players than was the original test.
Assuntos
Teste de Esforço , Tolerância ao Exercício , Consumo de Oxigênio/fisiologia , Resistência Física , Futebol/fisiologia , Adulto , Limiar Anaeróbio , Humanos , Masculino , Ventilação Voluntária Máxima/fisiologia , Troca Gasosa Pulmonar/fisiologia , Corrida/fisiologiaRESUMO
This study was designed to assess the effects of acute oral salbutamol and caffeine intake on performance and metabolism during short-term endurance exercise. Eight healthy volunteers participated in the double-blind placebo-controlled randomized cross-over study. Two 10 min cycling trials were performed at a power corresponding to 90 % VO 2 max for the first and a mock test for the second, separated by 10 min of passive recovery after ingestion of placebo (Pla), salbutamol (Sal, 6 mg) and caffeine (Caf, 250 mg). Performance (mean power during the mock test) was not statistically significant between the 3 treatments. Blood lactate was significantly increased after Sal compared to Pla at rest and until the end of the mock test whereas it appeared significantly increased after Caf compared to Pla at the end of the two exercises. Sal increased basal blood glucose and both Sal and Caf induced significant higher plasma insulin concentrations at rest, at the end of the mock test and during the recovery compared to Pla. No significant changes were found in these three variables between the Sal and the Caf treatments. Plasma growth hormone was significantly decreased after Sal after the mock test compared to the two other treatments. In conclusion, under the conditions of this study, neither oral salbutamol nor caffeine intake produce enhancement of short-term performance in non-specific trained subjects despite the substantial shifts in metabolic and hormonal parameters which were found.
Assuntos
Albuterol/farmacologia , Cafeína/farmacologia , Metabolismo Energético/efeitos dos fármacos , Exercício Físico/fisiologia , Administração Oral , Adulto , Glicemia/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Hormônio do Crescimento/sangue , Humanos , Insulina/sangue , Ácido Láctico/sangue , Masculino , Análise e Desempenho de TarefasRESUMO
The detection of exogenous 19-norandrosterone (19-NA) in urines was investigated by using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). 19-NA is, for the first time to our knowledge, isolated from urinary matrix by specific immunoaffinity chromatography (IAC) before analysis. The sample preparation consisted of a preliminary purification of urine by solid-phase extraction after hydrolysis by beta-glucuronidase. Unconjugated 19-NA was thus isolated by IAC and directly analysed by GC/C/IRMS. Optimisation of IAC purification was achieved and the reliability of the technique for anti-doping control is discussed.
Assuntos
Estranos/urina , Acetilação , Cromatografia de Afinidade , Estranos/imunologia , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Imunoquímica , Indicadores e Reagentes , SolventesRESUMO
A new method of detection of perfluorocarbon molecules (PFCs) in blood sample has been established. After an extraction and pre-concentration step performed by headspace solid-phase microextraction (HS-SPME), the PFCs are detected by gas chromatography-mass spectrometry (GC/MS) with an ion trap mass spectrometer in MS and MS/MS modes. The influence of different parameters on the SPME process is discussed. The limit of detection and the linearity of the procedure have been determined for two PFCs.
Assuntos
Fluorocarbonos/sangue , Cromatografia Gasosa-Espectrometria de Massas/métodos , Cromatografia Gasosa-Espectrometria de Massas/instrumentação , Humanos , Controle de Qualidade , Sensibilidade e Especificidade , TemperaturaRESUMO
Determination of whether the major metabolite of nandrolone in urine, 19-norandrosterone (19-NA), is exogenous or endogenous in origin is one of the most exciting challenges for antidoping laboratories. Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) can be used to differentiate these two origins by carbon isotopic ratio analysis. A complete method for purification of 19-NA in urine has been established. Acetylated ketosteroids, and in particular 19-NA, are isolated from the urine matrix before analysis after hydrolysis and purification of urine by reversed-phase and normal solid-phase extraction. The limit of detection for 19-NA was about 60 ng with recoveries of 54-60%. Evidence of exogenous administration of 19-NA may be established from isotope ratio determination from the 13C/12C ratios of several synthetic 19-norsteroids compared to those obtained for endogenous steroids.
Assuntos
Estranos/urina , Cromatografia Gasosa-Espectrometria de Massas/métodos , Dopagem Esportivo , Humanos , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
A detailed procedure for the analysis of exogenous hydrocortisone and cortisone in urine by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) is proposed. As urinary levels of hydrocortisone are rather low for GC/C/IRMS analysis, the focus is on the main corticosteroid metabolites, tetrahydrocortisone (THE) and tetrahydrocortisol (THF). Following different solid phase extraction purifications, THE and THF are oxidized to 5beta-androstanetrione before analysis by GC/C/IRMS. Significant differences in delta(13)C per thousand values of synthetic natural corticosteroids and endogenous human corticosteroids have been observed. Therefore, a positive criterion, to detect exogenous administration of synthetic corticosteroids in anti-doping control, is proposed.
Assuntos
Corticosteroides/administração & dosagem , Corticosteroides/urina , Cromatografia Gasosa-Espectrometria de Massas/métodos , Esportes , Corticosteroides/química , Corticosteroides/metabolismo , Adulto , Androstanos/química , Androstanos/urina , Cortisona/administração & dosagem , Cortisona/química , Cortisona/metabolismo , Cortisona/urina , Feminino , Humanos , Hidrocortisona/administração & dosagem , Hidrocortisona/química , Hidrocortisona/metabolismo , Hidrocortisona/urina , Masculino , Pessoa de Meia-Idade , Estrutura Molecular , Tetra-Hidrocortisol/química , Tetra-Hidrocortisol/urina , Tetra-Hidrocortisona/química , Tetra-Hidrocortisona/urina , Fatores de TempoRESUMO
To assess the eventual effects of acute oral salbutamol intake on performance and metabolism during submaximal exercise, nine healthy volunteers completed two cycling trials at a power corresponding to 80-85% VO2max, after either placebo (Pla) or salbutamol (Sal, 6 mg) treatment, according to a double-blind randomized protocol. Blood samples were collected both at rest and during exercise (5 min-, 10 min-, 15 min-exhaustion) for C-peptide, FFA, lactate and blood glucose measurements. Cycling performance was significantly improved in the Sal vs. Pla trials (p < 0.05). After Sal intake, resting C-peptide, lactate, FFA and blood glucose values were higher whereas exercise lactate and free fatty acid concentrations were greater during and at the conclusion of the exercise period (p < 0.05). These results suggest that acute salbutamol ingestion improved performance during submaximal exercise probably through an enhancement of the overall contribution to energy production from both aerobic and anaerobic metabolisms.
Assuntos
Agonistas Adrenérgicos beta/administração & dosagem , Albuterol/administração & dosagem , Tolerância ao Exercício/efeitos dos fármacos , Administração Oral , Adulto , Ciclismo , Glicemia/análise , Peptídeo C/sangue , Método Duplo-Cego , Metabolismo Energético/efeitos dos fármacos , Ácidos Graxos não Esterificados/sangue , Humanos , Lactatos/sangue , MasculinoRESUMO
A gas chromatography-mass spectrometry method (SIM mode) was developed for the determination of perfluorodecalin (cis and trans isomers, 50% each) (FDC), and perfluoromethylcyclohexylpiperidine (3 isomers) (FMCP) in rat blood. The chromatographic separation was performed by injection in the split mode using a CP-select 624 CB capillary column. Analysis was performed by electronic impact ionization. The ions m/z 293 and m/z 181 were selected to quantify FDC and FMCP due to their abundance and to their specificity, respectively. The ion m/z 295 was selected to monitor internal standard. Before extraction, blood samples were stored at -30 degrees C for at least 24 h in order to break the emulsion. The sample preparation procedure involved sample clean-up by liquid-liquid extraction. The bis(F-butyl)ethene was used as the internal standard. For each perfluorochemical compound multiple peaks were observed. The observed retention times were 1.78 and 1.87 min for FDC, and 2.28, 2.34, 2.48 and 2.56 min for FMCP. For each compound, two calibration curves were used; assays showed good linearity in the range 0.0195-0.78 and 0.78-7.8 mg/ml for FDC, and 0.00975-0.39 and 0.39-3.9 mg/ml for FMCP. Recoveries were 90 and 82% for the two compounds, respectively with a coefficient of variation <8%. Precision ranged from 0.07 to 15.6%, and accuracy was between 89.5 and 111.4%. The limits of quantification were 13 and 9 microg/ml for FDC and FMCP, respectively. This method has been used to determine the pharmacokinetic profile of these two perfluorochemical compounds in blood following administration of 1.3 g of FDC and 0.65 g of FMCP per kg body weight, in emulsion form, in rat.