A bioquímica do envelhecimento e obesidade
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Data
2011-02-08
Autores
Seiva, Fábio Rodrigues Ferreira [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O envelhecimento populacional mundial é considerado um processo relativamente novo na história da humanidade e está associado a melhorias na área de prevenção e tratamento na saúde publica, bem como à diminuição da taxa de fertilidade, elevando rapidamente assim, o número de pessoas com mais de 60 anos em vários países ao redor do mundo (ACEVEDO, 1998). Embora esse aumento possa ser visto como um ponto positivo, ainda é preciso alcançar também melhorias na qualidade de vida entre as pessoas idosas. Comorbidades e complicações advindas de processos que acompanham o envelhecimento, tais quais, diabetes, sobrepeso e obesidade, hipertensão arterial, doenças neurodegenerativas e principalmente complicações cardiovasculares, ainda são problemas, que além de onerarem o sistema único de saúde, elevam a taxa de mortalidade na população senil. GH, ou hormônio de crescimento, produzido e secretado na hipófise anterior, atua direta ou indiretamente, via IGF-I (hormônio de crescimento insulina-símile) produzido principalmente no fígado, levando ao crescimento longitudinal ósseo, muscular e das cartilagens. O GH também é um importante mediador de algumas vias metabólicas, como a oxidação lipídica. Em relação ao metabolismo dos carboidratos, o GH apresenta efeitos antagônicos aos efeitos clássicos da insulina, sendo por muitos, considerado um hormônio diabetogênico (COPELAND et al, 1990; HAJIMA et al, 2005)
Life expectancy is increasing in world population and with it, the incidence of public health problems such as obesity and cardiac alterations. Because growth hormone (GH) concentration is referred to be decreased in aging conditions, a question must be addressed: what is the effect of GH on aging related adverse changes? To investigate the effects of GH on cardiac energy metabolism and its association with calorimetric parameters, lipid profile and oxidative stress in aged and obese rats, initially 32 male Wistar rats were divided into two groups (n=16):(C) given standard-chow and water;(H) given hypercaloric-chow and receiving 30% sucrose in its drinking water. After 45 days, both C and H groups were divided into two subgroups (n=8):(C+PL) standard-chow, water and receiving saline subcutaneously;(C+GH) standard-chow, water and receiving 2 mg/kg/day rhGH subcutaneously;(H+PL) hypercaloricchow, 30% sucrose, receiving saline subcutaneously;(H+GH) hypercaloric-chow, 30% sucrose, receiving rhGH subcutaneously. After 30 days, C+GH and H+PL rats had higher body mass index, Lee-index, body fat content, percent-adiposity, serum triacylglycerol, cardiac lipid-hydroperoxide and triacylglycerol than C+PL. Energy-expenditure (RMR)/body weight, oxygen consumption and fat-oxidation were higher in H+GH than in H+PL. LDLcholesterol was highest in H+GH rats, whereas cardiac pyruvate-dehydrogenase and phosphofrutokinase activities were higher in H+GH and H+PL rats than in C+PL. In conclusion, the present study brought new insights on aging and obesity, demonstrating for the first time that GH therapy was harmful in aged and obesity conditions, impairing calorimetric parameters, lipid profile and oxidative stress. GH was disadvantageous in old rats, having undesirable effects on cardiac energy metabolism
Life expectancy is increasing in world population and with it, the incidence of public health problems such as obesity and cardiac alterations. Because growth hormone (GH) concentration is referred to be decreased in aging conditions, a question must be addressed: what is the effect of GH on aging related adverse changes? To investigate the effects of GH on cardiac energy metabolism and its association with calorimetric parameters, lipid profile and oxidative stress in aged and obese rats, initially 32 male Wistar rats were divided into two groups (n=16):(C) given standard-chow and water;(H) given hypercaloric-chow and receiving 30% sucrose in its drinking water. After 45 days, both C and H groups were divided into two subgroups (n=8):(C+PL) standard-chow, water and receiving saline subcutaneously;(C+GH) standard-chow, water and receiving 2 mg/kg/day rhGH subcutaneously;(H+PL) hypercaloricchow, 30% sucrose, receiving saline subcutaneously;(H+GH) hypercaloric-chow, 30% sucrose, receiving rhGH subcutaneously. After 30 days, C+GH and H+PL rats had higher body mass index, Lee-index, body fat content, percent-adiposity, serum triacylglycerol, cardiac lipid-hydroperoxide and triacylglycerol than C+PL. Energy-expenditure (RMR)/body weight, oxygen consumption and fat-oxidation were higher in H+GH than in H+PL. LDLcholesterol was highest in H+GH rats, whereas cardiac pyruvate-dehydrogenase and phosphofrutokinase activities were higher in H+GH and H+PL rats than in C+PL. In conclusion, the present study brought new insights on aging and obesity, demonstrating for the first time that GH therapy was harmful in aged and obesity conditions, impairing calorimetric parameters, lipid profile and oxidative stress. GH was disadvantageous in old rats, having undesirable effects on cardiac energy metabolism
Descrição
Palavras-chave
Envelhecimento, Obesidade, Somatotropina, Aging, Obesity
Como citar
SEIVA, Fábio Rodrigues Ferreira. A bioquímica do envelhecimento e obesidade. 2011. 58 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, 2011.