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Non-invasive Assessment of Dorsiflexor Muscle Function in Mice
https://tinyurl.com/yyqxqv7a



Effects of beta-hydroxy-beta-methylbutyrate (HMB) on the expression of ubiquitin ligases, protein synthesis pathways and contractile function in extensor digitorum longus (EDL) of fed and fasting rats

Dysregulation between TRIM63/FBXO32 expression and soleus muscle wasting in diabetic rats: potential role of miR-1-3p, -29a/b-3p, and -133a/b-3p.

http://link.springer.com/article/10.1007%2Fs11010-016-2910-z

Erythropoietin Does Not Enhance Skeletal Muscle Protein Synthesis Following Exercise in Young and Older Adult

http://journal.frontiersin.org/article/10.3389/fphys.2016.00292/full


 
1. Acta Physiol (Oxf). 2014 Sep;212(1):62-74. doi: 10.1111/apha.12336. Epub 2014 Jul
12.
Beta hydroxy beta methylbutyrate supplementation impairs peripheral insulin
sensitivity in healthy sedentary Wistar rats.

Yonamine CY(1), Teixeira SS, Campello RS, Gerlinger-Romero F, Rodrigues CF Jr,
Guimarães-Ferreira L, Machado UF, Nunes MT.

Author information: 
(1)Department of Physiology and Biophysics, Institute of Biomedical Sciences,
University of São Paulo, São Paulo, Brazil.

AIM: Investigate, in healthy sedentary rats, the potential mechanisms involved on
the effects of beta hydroxy beta methylbutyrate (HMB) supplementation upon the
glycaemic homeostasis, by evaluating the insulin sensitivity in liver, skeletal
muscle, and white adipose tissue.
METHODS: Rats were supplemented with either beta hydroxy beta methylbutyrate
(320 mg kg(-1)  BW) or saline by gavage for 4 weeks. After the experimental
period, the animals were subjected to the glucose tolerance test (GTT) and plasma
non-esterified fatty acids (NEFA) concentration measurements. The soleus skeletal
muscle, liver and white adipose tissue were removed for molecular (western
blotting and RT-PCR) and histological analysis.
RESULTS: The beta hydroxy beta methylbutyrate supplemented rats presented: (i)
higher ratio between the area under the curve (AUC) of insulinaemia and glycaemia
during glucose tolerance test; (ii) impairment of insulin sensitivity on liver
and soleus skeletal muscle after insulin overload; (iii) reduction of glucose
transporter 4 (GLUT 4) total and plasma membrane content on soleus; (iv)
increased hormone-sensitive lipase (HSL) mRNA and protein expression on white
adipose tissue and plasma NEFA levels and (v) reduction of fibre cross-sectional 
area of soleus muscle.
CONCLUSION: The data altogether indicate that beta hydroxy beta methylbutyrate
supplementation impairs insulin sensitivity in healthy sedentary rats, which, in 
the long-term, could lead to an increased risk of developing type 2 diabetes.


















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Eur J Appl Physiol. 2012 Nov;112(11):3905-11. doi: 10.1007/s00421-012-2378-9. Epub 2012


 Mar 14. Short-term creatine supplementation decreases reactive oxygen species 


content with no changes in expression and activity of antioxidant enzymes in skeletal 


muscle. Guimarães-Ferreira L, Pinheiro CH, Gerlinger-Romero F, Vitzel KF, Nachbar RT, 


Curi R, Nunes MT. Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, ICB-I, Cidade Universitária, Av. Prof. Lineu Prestes, 1524, Butantã, São Paulo, SP, 05508-900, Brazil. lucas@cefd.ufes.br



Erratum in Eur J Appl Physiol. 2012 Nov;112(11):3913.

The effect of short-term creatine (Cr) supplementation upon content of skeletal


 muscle-derived-reactive oxygen species (ROS) was investigated. Wistar rats were 


supplemented with Cr (5 g/kg BW) or vehicle, by gavage, for 6 days. Soleus and extensor


 digitorum longus (EDL) muscles were removed and incubated for evaluation of ROS content


 using Amplex-UltraRed reagent. The analysis of expression and activity of antioxidant 


enzymes (superoxide dismutase 1 and 2, catalase and glutathione peroxidase) were 


performed. Direct scavenger action of Cr on superoxide radical and hydrogen peroxide 


was also investigated. Short-term Cr supplementation attenuated ROS content in both 


soleus and EDL muscles (by 41 and  33.7%, respectively). Cr supplementation did not 


change expression and activity of antioxidant enzymes. Basal TBARS content was not 


altered by Cr supplementation. In cell-free experiments, Cr showed a scavenger effecton 


superoxide radical in concentrations of 20 and 40 mM, but not on hydrogen peroxide. 


These results indicate that Cr supplementation decreases ROS content in skeletal muscle 


possibly due to a direct action of Cr molecule on superoxide radical.






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Eur J Appl Physiol. 2012 Jul;112(7):2531-7. doi: 10.1007/s00421-011-2224-5. Epub  2011 


Nov 11.Metabolic and functional effects of beta-hydroxy-beta-methylbutyrate (HMB) 


supplementation in skeletal muscle.
Pinheiro CH, Gerlinger-Romero F, Guimarães-Ferreira L, de Souza-Jr AL, Vitzel KF,
Nachbar RT, Nunes MT, Curi R.
Department of Physiology and Biophysics, room 105, Institute of Biomedical Science, 


University of São Paulo, Av. Prof. Lineu Prestes, 1524, Prédio Biomédicas I, Cidade 


Universitária, Butantã, São Paulo, SP, CEP:05508-900, Brazil. chjpinheiro@gmail.com
Beta-hydroxy-beta-methylbutyrate (HMB) is a metabolite derived from leucine. 


The  anti-catabolic effect of HMB is well documented but its effect upon skeletal muscle 


strength and fatigue is still uncertain. In the present study, male Wistar rats were 


supplemented with HMB (320 mg/kg per day) for 4 weeks. Placebo group received saline 


solution only. Muscle strength (twitch and tetanic force) and resistance to acute muscle 


fatigue of the gastrocnemius muscle were evaluated by direct electrical stimulation of the 


sciatic nerve. The content of ATP and glycogen in red and white portions of gastrocnemius 


muscle were also evaluated. The effect of HMB on citrate synthase (CS) activity was also 


investigated. Muscle tetanic force was increased by HMB supplementation. No change 


was observed in time to peak of contraction and relaxation time. Resistance to acute muscle


 fatigue during intense contractile activity was also improved after HMB supplementation. 


Glycogen content was increased in both white (by fivefold) and red (by fourfold) portions 


of gastrocnemius muscle. HMB supplementation also increased the ATP content in red 


(by twofold) and white (1.2-fold) portions of gastrocnemius muscle. CS activity was increased


 by twofold in red portion of gastrocnemius muscle. These results support the proposition 


that HMB supplementation have marked change in oxidative metabolism improving muscle 


strength generation and performance during intense contractions.













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 2011 Apr;21(2):57-62. doi: 10.1016/j.ghir.2010.12.006. Epub 2011 Jan 14.

Chronic supplementation of beta-hydroxy-beta methylbutyrate (HMβ) increases the activity of the GH/IGF-I axis and induces hyperinsulinemia in rats.



Gerlinger-Romero F, Guimarães-Ferreira L, Giannocco G, Nunes MT.






Source



Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo. Av. Prof. Lineu Prestes, São Paulo/SP, Brazil.

Abstract



OBJECTIVE:Beta-hydroxy-beta-methylbutyrate (HMβ) is a metabolite of leucine widely used for improving sports performance. Although HMβ is recognized to promote anabolic or anti-catabolic effects on protein metabolism, the impact of its long-term use on skeletal muscle and/or genes that control the skeletal protein balance is not fully known. This study aimed to investigate whether chronic HMβ treatment affects the activity of GH/IGF-I axis and skeletal muscle IGF-I and myostatin mRNA expression.













DESIGN:





Rats were treated with HMβ (320mg/kg BW) or vehicle, by gavage, for 4 weeks, and killed by decapitation. Blood was collected for evaluation of serum insulin, glucose and IGF-I concentrations. Samples of pituitary, liver, extensor digitorum longus (EDL) and soleus muscles were collected for total RNA or protein extraction to evaluate the expression of pituitary growth hormone (GH) gene (mRNA and protein), hepatic insulin-like growth factor I (IGF-I) mRNA, skeletal muscle IGF-I and myostatin mRNA by Northern blotting/real time-PCR, or Western blotting.







RESULTS:



Chronic HMβ treatment increased the content of pituitary GH mRNA and GH, hepatic IGF-I mRNA and serum IGF-I concentration. No changes were detected on skeletal muscle IGF-I and myostatin mRNA expression. However, the HMβ-treated rats although normoglycemic, exhibited hyperinsulinemia.




CONCLUSIONS:





The data presented herein extend the body of evidence on the potential role of HMβ-treatment in stimulating GH/IGF-I axis activity. In spite of this effect, HMβ supplementation also induces an apparent insulin resistance state which might limit the beneficial aspects of the former results, at least in rats under normal nutritional status and health conditions.















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 2011 Apr;40(4):1015-25. doi: 10.1007/s00726-010-0678-0. Epub 2010 Jul 6.




HMB supplementation: clinical and athletic performance-related effects and mechanisms of action.



Zanchi NE, Gerlinger-Romero F, Guimarães-Ferreira L, de Siqueira Filho MA, Felitti V, Lira FS, Seelaender M, Lancha AH Jr.






Source



Laboratory of Applied Nutrition and Metabolism, Physical Education and Sports School, University of Sao Paulo, São Paulo, Brazil. neloz@ig.com.br















Abstract





Amino acids such as leucine and its metabolite α-ketoisocaproate (KIC), are returning to be the focus of studies, mainly because of their anti-catabolic properties, through inhibition of muscle proteolysis and enhancement of protein synthesis. It is clear that these effects may counteract catabolic conditions, as well as enhance skeletal muscle mass and strength in athletes. Moreover, beta-hydroxy-beta-methylbutyrate (HMB) has been shown to produce an important effect in reducing muscle damage induced by mechanical stimuli of skeletal muscle. This review aims to describe the general scientific evidence of KIC and HMB supplementation clinical relevance, as well as their effects (e.g., increases in skeletal muscle mass and/or strength), associated with resistance training or other sports. Moreover, the possible mechanisms of cell signaling regulation leading to increases and/or sparing (during catabolic conditions) of skeletal muscle mass are discussed in detail based on the recent literature.















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J Int Soc Sports Nutr. 2010 Nov 8;7:36. doi: 10.1186/1550-2783-7-36.



PAKs supplement improves immune status and body composition but not muscle
strength in resistance trained individuals.
Romero FG, Lira FS, Marques FA, Muzy PC, Peres RA, Caperuto EC.
Department of Biodynamic, Mackenzie Presbiterian University, São Paulo, Brazil.
ecaperuto@yahoo.com.



Mixed formula supplements are very popular among recreational and professional weightlifters. They are usually known as PAKs and they are supposed to have a synergistic effect of their different nutrients. The purpose of this study was to determine the effects of chronic (4 weeks) PAKS supplementation in combination with strength training on body composition, immune status and performance measures in recreationally trained individuals with or without PAKs supplementation. Methods: Twelve male subjects (Placebo n = 6 and PAKs supplement n = 6) were recruited for this study. The body composition, one maximum strength repetition tests and immune status were assessed before and after 4 week supplementation. Our data showed that, 4 week PAK supplementation associated with strength exercise not was effective in change strength than compared with placebo group. However, we observed that, PAK supplement was able to improve immune status and reduced body composition when compared with placebo group. These results indicate that, a mixed formula supplement is able to improve immune status and body composition but not maximum strength in recreational strength trained subjects in a 4 weeks period.





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ARTIGOS NACIONAIS
Frederico Gerlinger-Romero, Érico Chagas Caperuto, Adriano Fortes Maia, Lucas Guimarães-Ferreira
Bases moleculares das ações da testosterona, hormônio do crescimento e IGF-1 sobre a hipertrofia muscular esquelética e respostas ao treinamento de força
Revista Mackenzie de Educação Física e Esporte – v. 12, n. 2, 2013, p. 187-208

Resumo
Os hormônios testosterona, hormônio do crescimento (GH) e fator de crescimento semelhante à insulina 1 (IGF-1) são importantes reguladores da massa muscular, modulando os processos de síntese e degradação proteica. O presente trabalho tem como objetivo discutir as bases moleculares das ações desses hormônios na musculatura esquelética, as respostas agudas e crônicas, bem como a possível influência nas adaptações neuromusculares ao treinamento de força. A manipulação das variáveis do treinamento, como volume, intensidade, intervalos de repouso e grupos musculares utilizados influenciam diretamente as respostas hormonais. O aumento da secreção de hormônios anabólicos poderia contribuir para as adaptações crônicas – hipertrofia muscular – decorrentes do treinamento. No entanto, a importância da resposta hormonal para estas adaptações ainda é questionada e precisa ser mais bem investigada.

Palavras-chave: testosterona; hormônio do crescimento; treinamento de força.
ROMERO, F.G.; CAPERUTO, E.C.; COSTA ROSA, L.F.B.P. 
Efeitos de diferentes métodos de exercícios resistidos sobre o comportamento hemodinâmico 
R. bras. Ci e Mov. 2005;13(2):7-15.
RESUMO – O propósito do presente estudo foi verificar os efeitos ou respostas fisiológicas – relacionadas a pressão arterial sobre os exercícios resistidos. Foi analizado o comportamento da pressão arterial (utilizou se 80% de 1RM) durante e após a realização dos exercícios resistidos, o efeito da intensidade e variações de métodos. Os voluntários (n=9) realizaram dois métodos de treinamento o alternado por segmento (A.S.) e o localizado por segmento (L.S.), ou seja, os grandes grupos musculares de membro inferior e superior realizados seguidamente e posteriormente alternando os segmentos, com um período de descanso de um treino para o outro de 24 horas. Para comparar as diferenças entre os dois métodos de treinamento, o comportamento da pressão arterial no período pós-exercício suas alterações, magnitude e duração, utilizou-se para as variáveis mensuradas o teste-t de Student (p<0,05). Concluímos que não ocorreram diferença estatisticamente significativa no comportamento da pressão arterial durante a realização dos dois métodos, sendo apontada um hipotensão pós-exercício estatística em ambos, entretanto no método L.S. esta hipotensão com relação aos valores pressão arterial sistólica foi mais prolongada em comparação ao método A.S.
PALAVRAS-CHAVE - Exercícios Resistidos, Hipotensão pós-exercício, Métodos de Treinamento

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