Controle neuroendócrino da massa óssea: mito ou verdade?

Objective: To verify the influence of visceral and subcutaneous fat, as well adipokines in bone mineral density (BMD) in obese adolescents. Subjects and methods: The study involved 125 postpubertal obese adolescents (45 boys and 80 girls). Anthropometric measurements, body composition, visceral and subcutaneous fat, and BMD were determined. Leptin, adiponectin, and insulin levels also analyzed. Results: Data demonstrated a negative relationship between BMD with insulin resistance, visceral fat and leptin concentration; and bone mineral content with visceral/subcutaneous ratio. Positive association between BMD and subcutaneous fat was observed. Conclusions: Visceral fat and insulin resistance, as well as visceral/subcutaneous ratio and leptin concentration, were negative predictors of BMD in boys and girls, respectively. However, subcutaneous fat had a protective influence in BMD only in boys. Arq Bras Endocrinol Metab.2012;56(1):12-8 Keywords Adolescent; visceral fat; subcutaneous fat; bone mass RESUMO Objetivo: Verificar a influência da gordura visceral e subcutânea, assim como das adipocinas na densidade mineral óssea (DMO) em adolescentes obesos. Sujeitos e métodos: O estudo envolveu 125 adolescentes obesos pós-púberes. Medidas antropométricas, composição corporal, gordura visceral e subcutânea e DMO foram determinadas. Níveis de leptina, adiponectina e insulina foram analisados. Resultados: Os dados demonstraram associação negativa entre DMO com resistência insulínica, gordura visceral e concentração de leptina; e conteúdo mineral ósseo com a razão visceral/subcutânea. Associação positiva entre DMO e gordura subcutânea foi observada. Conclusões: Gordura visceral, resistência insulínica, razão visceral/subcutânea e concentração de leptina foram preditores negativos da DMO em meninos e meninas, respectivamente. Entretanto, a gordura subcutânea demonstrou exercer influência positivamente na DMO somente nos meninos. Arq Bras Endocrinol Metab. 2012;56(1):12-8 Descritores Adolescente; gordura visceral; gordura subcutânea; massa óssea

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“…It appears that leptin action may depend on their location of action, differentiating the effects central of peripheral. (37)(38)(39).…”

Section: Discussionmentioning

confidence: 99%

Influence of visceral and subcutaneous fat in bone mineral density of obese adolescents

Campos

Lazaretti-Castro

Mello

et al. 2012

Arq Bras Endocrinol Metab

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“…It acts directly through the binding of GH to its receptors in the growth plate and indirectly acting on growth in the cell differentiation process and in the synthesis of type-I collagen. These GH biological effects are mostly mediated by growth promotion factors similar to the insulin, known as IGFs (insulin-like growth factors), and the main factor is the IGF-1 (5,7,13,14,16) .…”

Section: Hormonal Actions On Growth During Childhood and Adolescencementioning

confidence: 99%

“…In skeleton, IGF-1 plays important role such as the differentiation maturation and recruitment of osteoblasts (16) . In the blood stream, IGF-1 is associated to binding proteins, being known as IGFBPs (binding protein).…”

Section: Hormonal Actions On Growth During Childhood and Adolescencementioning

confidence: 99%

“…Remarkably, IGFBP-3 is the main binding protein and has its production stimulated by GH (4,5,13,14) . The regulatory system of the GH/IGF-1 axis does not involve only endocrine actions, but also paracrine and autocrine IGF-1 actions (16) . The IGF-1 acts singularly for both genders, being the main mediator of the growth linear speed up involved in the determination of the bone thickness, length, density and skeletal structure, increasing the body proportions during childhood and adolescence (8,16) .…”

Section: Hormonal Actions On Growth During Childhood and Adolescencementioning

confidence: 99%

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O exercício físico potencializa ou compromete o crescimento longitudinal de crianças e adolescentes? Mito ou verdade?

Silva¹,

Goldberg²,

Teixeira³

et al. 2004

Rev Bras Med Esporte

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Modern society has given a lot of value to being slim and tall. This physical structure has been reinforced since childhood and has been affecting the adolescents desire to fit in this stereotype, especially the ones shown in the media. Because of this, health professionals are frequently questioned about the positive effects that physical exercises perform on children and adolescent's linear growth. Through the specialized literature, this article intended to illustrate the main effects that physical exercise would perform on the secretion of growth hormone (GH) in the several body tissues during childhood and adolescence. Through this reviewing, it was possible to verify that physical exercises induce the stimulation of the GH/IGF-1 axis. Although much is speculated with regard to physical exercise and bone growth, no well-developed studies were found in the specific scientific literature to corroborate this statement. The adverse physical practicing effects during childhood and adolescence, apparently, were independent of the type of the exercise practice, but else a result of the intensity. The high training intensity seems to cause an important metabolic modulation with raise of the inflammatory markers and the suppression of the GH/ IGF-1 axis. However, it is important to emphasize that the sportive modality itself selects children and/or adolescents with lower stature as strategy for the attainment of better results in function of the mechanical facility of movements. Through this research, the performance of linear studies is evident, where individuals are followed before, during, and after exercise, with the determination of the training volume and intensity in order to reach definitive conclusions with regard to the effects on the final stature.

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“…Os IGFs atuam como o principal mediador do crescimento, auxiliando na determinação da espessura óssea, comprimento, além da densidade e arquitetura do esqueleto, aumentando as proporções corporais durante a infância e adolescência (BORBA et al, 2003) Os IGFs associam-se às IGFBPs que, além de acrescer a vida média dos IGFs ainda modulam suas ações endócrinas, autócrinas e parácrinas, podendo tanto intensificá-las quanto inibi-las. Assim como os IGFs, as IGFBPs são sintetizadas em diversos órgãos e tecidos do organismo.…”

Section: Sistema Igf-1-igfbpsunclassified

Efeitos da suplementação de zinco, magnésio e vitamina B6 sobre o sistema IGF de atletas jovens

Cerqueira¹

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Julgamento: ____________________________________________________________ AGRADECIMENTOS Agradeço à minha família pelo apoio e força em todos os momentos difíceis durante esta jornada até aqui.À minha namorada Mariana e amigos, com os quais compartilhei momentos bons e também vários ruins, e que sempre me deram força nesses momentos.Aos professores da EEFERP-USP, Enrico Fuini Puggina e Hugo Tourinho Filho que, além de muito me ensinarem, foram os responsáveis por me apresentar à este fascinante "mundo" da pós-graduação e da pesquisa científica, há mais de 5 anos.Principalmente o Hugo, que tanto me apoiou e auxiliou desde então, sem ele eu jamais teria chegado aqui.Ao meu orientador, professor Carlos Eduardo Martinelli Jr., por todo o apoio, paciência e auxílio no desenvolvimento não só desta pesquisa, mas no meu crescimento como pós-graduando e pessoa. The GH-IGF system has several anabolic effects and plays an important role in strength gain. Some studies suggest that Zinc, Magnesium and Pyridoxine ("ZMA") supplementation could increase GH/IGF and testosterone levels in young subjects. This hypothetical increase could lead to significant changes in body composition. ZMA is a very popular supplement, easily found in specialty stores, and it is presumed to cause increasing in GH/IGF and testosterone levels. However, studies are divergent regarding its efficacy. Therefore, the present study aimed to verify the effects of physical training associated with 8-week ZMA supplementation on the IGF-1, IGFBP-3 and testosterone levels in young males. Eighteen healthy male amateur football players were included in the study. They were divided into two groups: ZMA (supplemented group) and placebo.IGF-1, IGFBP-3 and testosterone concentrations were higher in the final evaluation (8 weeks) than at the beginning of the study. The increase was similar in the supplemented and in the placebo group. Both groups showed similar changes in anthropometric parameters attesting for lean mass gain and decrease in body fat mass. The findings suggest that extra doses of the micronutrients present in the ZMA do not bring any additional benefits, either in the body composition or in the hormonal levels in subjects under adequate diet.

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Controle neuroendócrino da massa óssea: mito ou verdade?

Cited by 5 publications

References 34 publications

Influence of visceral and subcutaneous fat in bone mineral density of obese adolescents

Influence of visceral and subcutaneous fat in bone mineral density of obese adolescents

O exercício físico potencializa ou compromete o crescimento longitudinal de crianças e adolescentes? Mito ou verdade?

Efeitos da suplementação de zinco, magnésio e vitamina B6 sobre o sistema IGF de atletas jovens

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