Análise do potencial mutagênico dos esteroides anabólicos androgênicos (EAA) e da l-carnitina mediante o teste do micronúcleo em eritrócitos policromáticos

INTRODUCTION: Anabolic androgenic steroids (AAS) are frequently used by people whose aim to increase muscle mass to obtain a better performance in sports or improve physical appearance. AAS are synthetic derivatives of testosterone, able to promote muscle fibers hypertrophy, increasing intracellular protein synthesis. L-carnitine is a food supplement used to increase energetic production by means of fat acids oxidation. Although there are several works about physiological properties of these drugs, there are few studies about their mutagenic potential. OBJECTIVES: This work evaluated the clastogenicity and genotoxicity of nandrolone decanoate, testosterone decanoate and L-carnitine, in different treatments through the micronucleus test in polychromatic erythrocytes of Wistar rats. METHODS: The animals were submitted to different concentrations and associations of AAS. The positive control received cyclophosphamide 50 mg/kg by intraperitoneal injection and negative control, one ml of saline solution by gavage. The rats were sacrificed after 36 hours of latest application, having the femurs removed and the bone marrow extracted. Material was homogenized and centrifuged. Button cell was pipetted and transferred to slides, which were stained by Giemsa. 1,000 polychromatic erythrocytes were counted per animal, noting the frequency of micronuclei. RESULTS: The Kruskal-Wallis test was performed, with a significance level of 5%, which demonstrated that nandrolone decanoate - three doses of 0,2 mg/kg and 0,6 mg/kg, eight doses of 7,5 mg/kg, L-carnitine - seven doses of 0,4 ml/250 g and 1,5 ml/250 g, testosterone decanoate - 28 doses of 0,075 mg/kg, nandrolone decanoate - eight doses of 7,5 mg/kg associated to L-carnitine and 1 mL and nandrolone decanoate - eight doses of 7,5 mg/kg associated to testosterone decanoate - eight doses of 7,5 mg/kg, showed mutagenic potential. CONCLUSION: The treatments proved to be clastogenic, not being indicated like ergogenic aid.

Hypusine Modification of the Ribosome-binding Protein eIF5A, a Target for New Anti-Inflammatory Drugs: Understanding the Action of the Inhibitor GC7 on a Murine Macrophage Cell Line

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The use of stable isotopes to investigate the effects of supplemental lysine and methionine on protein turnover and amino acid utilization in pacu, Piaractus mesopotamicus, juveniles

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of feeding corn silage inoculated with microbial additives on the ruminal fermentation, microbial protein yield, and growth performance of lambs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Different true-protein sources do not modify the metabolism of crossbred Bos taurus x Bos indicus growing heifers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Alterations of protein expression in conditions of copper-deprivation for Paracoccidioides lutzii in the presence of extracellular matrix components

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Metabolism and ruminal parameters of Holstein × Gir heifers fed sugarcane and increasing levels of crude protein

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos do treinamento resistido sobre secreação de testosterona e cortisol: uma revisão bibliográfica

You can set the resistance training such as making a move against a resistance by performing a muscle contraction and generating a muscular adaptation. This form of training, was initially used only in training athletes aiming to strengthen and improve fitness. Some coaches did not give proper focus, as the increase in muscle mass would cause loss of flexibility and agility. But over time a huge evolution occurred within this area and the practitioners of resistance training are no longer just athletes, and reached the whole community, from young to elderly, being a physical activity that generates a large caloric expenditure and has several health benefits, improve the cardiovascular system and decreasing the amount of body fat in the body. Cortisol is a hormone secreted from a stressful stimulus to the body, secretion undergoes control of the hypothalamic-pituitary axis, which releases the hormone into the bloodstream andrenocorticotrópico, going to the adrenal cortex responsible for their release. This has catabolic function, acting in the metabolism of carbohydrates, proteins and lipids, as well as having an important effect antiflamatório. Testosterone is a steroid hormone cholesterol from being produced by the testicles in men, as in women is produced to a lesser extent in ovary and adrenal glands, has functions androgenic and anabolic. Androgen function is responsible for the development of male sexual characteristics, while on anabolic function operates in the growth of muscles and bones, influencing the development of the human body organs. Within the metabolic changes that occur in the resistance training testosterone plays an important role in protein synthesis, influencing the production of strength and / or power during exercise. The objective of this work is through a literature review to assess the effects of resistance training on the production of these hormones and the relationship between them

Clenbuterol suppresses proteasomal and lysosomal proteolysis and atrophy-related genes in denervated rat soleus muscles independently of Akt

Goncalves DA, Silveira WA, Lira EC, Gra a FA, Paula-Gomes S, Zanon NM, Kettelhut IC, Navegantes LC. Clenbuterol suppresses proteasomal and lysosomal proteolysis and atrophy-related genes in denervated rat soleus muscles independently of Akt. Am J Physiol Endocrinol Metab 302: E123-E133, 2012. First published September 27, 2011; doi:10.1152/ajpendo.00188.2011.-Although it is well known that administration of the selective beta(2)-adrenergic agonist clenbuterol (CB) protects muscle following denervation (DEN), the underlying molecular mechanism remains unclear. We report that in vivo treatment with CB (3 mg/kg sc) for 3 days induces antiproteolytic effects in normal and denervated rat soleus muscle via distinct mechanisms. In normal soleus muscle, CB treatment stimulates protein synthesis, inhibits Ca(2+)-dependent proteolysis, and increases the levels of calpastatin protein. On the other hand, the administration of CB to DEN rats ameliorates the loss of muscle mass, enhances the rate of protein synthesis, attenuates hyperactivation of proteasomal and lysosomal proteolysis, and suppresses the transcription of the lysosomal protease cathepsin L and of atrogin-1/MAFbx and MuRF1, two ubiquitin (Ub) ligases involved in muscle atrophy. These effects were not associated with alterations in either IGF-I content or Akt phosphorylation levels. In isolated muscles, CB (10(-6) M) treatment significantly attenuated DEN-induced overall proteolysis and upregulation in the mRNA levels of the Ub ligases. Similar responses were observed in denervated muscles exposed to 6-BNZ-cAMP (500 mu M), a PKA activator. The in vitro addition of triciribine (10 mu M), a selective Akt inhibitor, did not block the inhibitory effects of CB on proteolysis and Ub ligase mRNA levels. These data indicate that short-term treatment with CB mitigates DEN-induced atrophy of the soleus muscle through the stimulation of protein synthesis, downregulation of cathepsin L and Ub ligases, and consequent inhibition of lysosomal and proteasomal activities and that these effects are independent of Akt and possibly mediated by the cAMP/PKA signaling pathway.

Potential Contribution of Translational Factors to Triiodo-L-Thyronine-Induced Insulin Synthesis by Pancreatic Beta Cells

Background: Thyroid hormones (THs) are known to regulate protein synthesis by acting at the transcriptional level and inducing the expression of many genes. However, little is known about their role in protein expression at the post-transcriptional level, even though studies have shown enhancement of protein synthesis associated with mTOR/p70S6K activation after triiodo-l-thyronine (T3) administration. On the other hand, the effects of TH on translation initiation and polypeptidic chain elongation factors, being essential for activating protein synthesis, have been poorly explored. Therefore, considering that preliminary studies from our laboratory have demonstrated an increase in insulin content in INS-1E cells in response to T3 treatment, the aim of the present study was to investigate if proteins of translational nature might be involved in this effect. Methods: INS-1E cells were maintained in the presence or absence of T3 (10(-6) or 10(-8) M) for 12 hours. Thereafter, insulin concentration in the culture medium was determined by radioimmunoassay, and the cells were processed for Western blot detection of insulin, eukaryotic initiation factor 2 (eIF2), p-eIF2, eIF5A, EF1A, eIF4E binding protein (4E-BP), p-4E-BP, p70S6K, and p-p70S6K. Results: It was found that, in parallel with increased insulin generation, T3 induced p70S6K phosphorylation and the expression of the translational factors eIF2, eIF5A, and eukaryotic elongation factor 1 alpha (eEF1A). In contrast, total and phosphorylated 4E-BP, as well as total p70S6K and p-eIF2 content, remained unchanged after T3 treatment. Conclusions: Considering that (i) p70S6K induces S6 phosphorylation of the 40S ribosomal subunit, an essential condition for protein synthesis; (ii) eIF2 is essential for the initiation of messenger RNA translation process; and (iii) eIF5A and eEF1A play a central role in the elongation of the polypeptidic chain during the transcripts decoding, the data presented here lead us to suppose that a part of T3-induced insulin expression in INS-1E cells depends on the protein synthesis activation at the post-transcriptional level, as these proteins of the translational machinery were shown to be regulated by T3.

Aerobic exercise training upregulates skeletal muscle calpain and ubiquitin-proteasome systems in healthy mice

Cunha TF, Moreira JB, Paixao NA, Campos JC, Monteiro AW, Bacurau AV, Bueno CR Jr., Ferreira JC, Brum PC. Aerobic exercise training upregulates skeletal muscle calpain and ubiquitin-proteasome systems in healthy mice. J Appl Physiol 112: 1839-1846, 2012. First published March 29, 2012; doi:10.1152/japplphysiol.00346.2011.-Aerobic exercise training (AET) is an important mechanical stimulus that modulates skeletal muscle protein turnover, leading to structural rearrangement. Since the ubiquitin-proteasome system (UPS) and calpain system are major proteolytic pathways involved in protein turnover, we aimed to investigate the effects of intensity-controlled AET on the skeletal muscle UPS and calpain system and their association to training-induced structural adaptations. Long-lasting effects of AET were studied in C57BL/6J mice after 2 or 8 wk of AET. Plantaris cross-sectional area (CSA) and capillarization were assessed by myosin ATPase staining. mRNA and protein expression levels of main components of the UPS and calpain system were evaluated in plantaris by real-time PCR and Western immunoblotting, respectively. No proteolytic system activation was observed after 2 wk of AET. Eight weeks of AET resulted in improved running capacity, plantaris capillarization, and CSA. Muscle RING finger-1 mRNA expression was increased in 8-wk-trained mice. Accordingly, elevated 26S proteasome activity was observed in the 8-wk-trained group, without accumulation of ubiquitinated or carbonylated proteins. In addition, calpain abundance was increased by 8 wk of AET, whereas no difference was observed in its endogenous inhibitor calpastatin. Taken together, our findings indicate that skeletal muscle enhancements, as evidenced by increased running capacity, plantaris capillarization, and CSA, occurred in spite of the upregulated UPS and calpain system, suggesting that overactivation of skeletal muscle proteolytic systems is not restricted to atrophying states. Our data provide evidence for the contribution of the UPS and calpain system to metabolic turnover of myofibrillar proteins and skeletal muscle adaptations to AET.

The beta 2-Adrenoceptor Agonist Formoterol Improves Structural and Functional Regenerative Capacity of Skeletal Muscles From Aged Rat at the Early Stages of Postinjury

Skeletal muscles from old rats fail to completely regenerate following injury. This study investigated whether pharmacological stimulation of beta 2-adrenoceptors in aged muscles following injury could improve their regenerative capacity, focusing on myofiber size recovery. Young and aged rats were treated with a subcutaneous injection of beta 2-adrenergic agonist formoterol (2 mu g/kg/d) up to 10 and 21 days after soleus muscle injury. Formoterol-treated muscles from old rats evaluated at 10 and 21 days postinjury showed reduced inflammation and connective tissue but a similar number of regenerating myofibers of greater caliber when compared with their injured controls. Formoterol minimized the decrease in tetanic force and increased protein synthesis and mammalian target of rapamycin phosphorylation in old muscles at 10 days postinjury. Our results suggest that formoterol improves structural and functional regenerative capacity of regenerating skeletal muscles from aged rats by increasing protein synthesis via mammalian target of rapamycin activation. Furthermore, formoterol may have therapeutic benefits in recovery following muscle damage in senescent individuals.

Potential therapeutic effects of branched-chain amino acids supplementation on resistance exercise-based muscle damage in humans

Branched-chain amino acids (BCAA) supplementation has been considered an interesting nutritional strategy to improve skeletal muscle protein turnover in several conditions. In this context, there is evidence that resistance exercise (RE)-derived biochemical markers of muscle soreness (creatine kinase (CK), aldolase, myoglobin), soreness, and functional strength may be modulated by BCAA supplementation in order to favor of muscle adaptation. However, few studies have investigated such effects in well-controlled conditions in humans. Therefore, the aim of this short report is to describe the potential therapeutic effects of BCAA supplementation on RE-based muscle damage in humans. The main point is that BCAA supplementation may decrease some biochemical markers related with muscle soreness but this does not necessarily reflect on muscle functionality.

Interaction of leptospira elongation factor tu with plasminogen and complement factor h: a metabolic leptospiral protein with moonlighting activities

The elongation factor Tu (EF-Tu), an abundant bacterial protein involved in protein synthesis, has been shown to display moonlighting activities. Known to perform more than one function at different times or in different places, it is found in several subcellular locations in a single organism, and may serve as a virulence factor in a range of important human pathogens. Here we demonstrate that Leptospira EF-Tu is surface-exposed and performs additional roles as a cell-surface receptor for host plasma proteins. It binds plasminogen in a dose-dependent manner, and lysine residues are critical for this interaction. Bound plasminogen is converted to active plasmin, which, in turn, is able to cleave the natural substrates C3b and fibrinogen. Leptospira EF-Tu also acquires the complement regulator Factor H (FH). FH bound to immobilized EF-Tu displays cofactor activity, mediating C3b degradation by Factor I (FI). In this manner, EF-Tu may contribute to leptospiral tissue invasion and complement inactivation. To our knowledge, this is the first description of a leptospiral protein exhibiting moonlighting activities

In-vitro synthesis and reconstitution of cytochrome bo 3 ubiquinol oxidase in artificial membranes

Forschung über Membranenproteine stellt strenge Hindernisse, seit ruhigem gerade wenige Beispiele der Membranenproteinsorten sind gekennzeichnet worden in den verwendbaren experimentellen Plattformen gegenüber. Die Hauptherausforderung ist, ihre ausgezeichnete entworfene strukturelle Vollständigkeit zu konservieren, während die Ausdruck-, Lokalisierungs- und Wiederherstellungprozesse auftreten. In-vitro übersetzungssysteme können Vorteile über auf Zellenbasisgenausdruck zum Beispiel haben, wenn das über-ausgedrückte Produkt zur Wirtszelle giftig ist oder wenn fehlende Pfosten-Übersetzungsänderung in den bakteriellen Ausdrucksystemen die Funktionalität der Säugetier- Proteine oder Mangel an vorhandenem Membranenraum verdirbt, Funktionsausdruck verbieten.rn Der Nachahmer von biologische Membranen wie feste gestützte Lipidmembranen sind als Plattform am meisten benutzt, Proteinmembraneninteraktionen nachzuforschen. Wir sind in der Lage, Membranenproteinsorte, da wir eine Plattform für Membranenproteinsynthese vorstellen, nämlich die in-vitrosynthese der Membranenproteine in ein Peptid gestütztes Membranensystem zu adressieren. Die Wiederherstellung der Membranenproteine in den Lipid bilayers resultiert im Allgemeinen mit verschiedenen Proteinanpassungen. Als Alternative erforschen wir dieses System zum ersten Mal, um genaueres Modell zu den zellularen Membranen zu verursachen und ihre Funktion, wie Proteineinfügung, Proteinfunktion und Ligandinteraktionen nachzuahmen.rn In dieser Arbeit ist unser Ziel, komplizierte Transmembraneproteine, wie des Cytochrome bo3-ubiquinol Oxydase (Cyt-bo3) direkt innerhalb der biomimetic vorbildlichen Membrane zu synthetisieren. In unserem System wird festes gestütztes tBLM wie, P19/DMPE/PC als Plattform benutzt. Dieses künstliche Membranensystem mimiks die amphiphile Architektur eines Zelle-abgeleiteten Membranensystems.rn