During intense exercise there is an augmented production of ammonia and IMP in the exercised muscle that could be related to the establishment of peripheral fatigue. In order to prevent this accumulation, the urea cycle in the liver eliminates ammonia in the form of urea and the skeletal muscle buffers the increase of ammonia via transamination reactions. In the present study we evaluated the effect of arginine, citrulline and ornithine supplementation, intermediates of the urea cycle, on the performance of sedentary and swimming-trained rats submitted to a single bout of exhaustive exercise. We also measured the glycogen content of the soleus and gastrocnemius muscles and of the liver, as well as the plasma concentrations of ammonia, urea, glutamine, glucose and lactate. The results indicate that arginine, citrulline and ornithine supplementation increased the flux of substrate through the reaction catalysed by glutamine synthetase, leading to increased glutamine production after an exhaustive bout of exercise, and of the mechanism involved in ammonia buffering.
Although aging compromises the functionality of macrophages (MΦ) and lymphocytes (LY), and dietary restriction (DR) and exercise partially counterbalance immunosenescence, it is unknown what effects of both strategies have on the functionality of these immune cells. Rats were randomly distributed into adult control (AD), older group (OLD), older submitted to 50% of DR (DR) and older submitted to swimming (EX) (n = 10 in each group). The function of immune cells (proliferative index, phagocytic capacity and H₂O₂ production), the weight and protein content of lymphoid organs (thymus and spleen), plasma glutamine concentration, interleukins (IL-1, IL-2, IL-6) and, immunoglobulins (IgA and IgG) were analysed. There was an increase of 74% in body weight in aged animals as compared with the AD group, while body weight reduced 19% in the DR as compared with the OLD group. Swimming training stimulated MΦ phagocytosis, while the EX group presented a decrease of the proliferative capacity of LY from the mesenteric lymph nodes (44% and 62%, respectively), when stimulated with ConA and LPS as compared with the old rats. These data demonstrated that DR and exercise affects differentially MΦ and LY function.
A AG GR RA AD DE EC CI IM ME EN NT TO OS S Dedico esta Tese:A minha família: Rubens, Clara, Fernando e a "caçula" Cynara;Ao meu amor, Alberto;Ao GG pela amizade, paciência, dedicação e confiança imprescindível na minha formação acadêmica, desde os tempos de iniciação científica... E também, por me levar a estudar este maravilhoso assunto que é o envelhecimento!
Agradeço:Ao "Grande Arquiteto do Universo" e a todos os "amigos" que sempre me acompanham e auxiliam...
Aos meus grandes amigos Mônica Aparecida Belmonte e ÉricoChagas Caperuto companheiros de "viagem", que estão sempre por perto, principalmente nas horas mais conturbadas.Ao Reury Frank Pereira Bacurau pela amizade, pelas conversas que tanto enriquecem nosso cotidiano e pelo auxílio nas horas de "histeria".Ao Francisco Navarro pelos "empurrões" na vida prática, e exemplo de força de vontade e persistência. À Gabriela Chamusca (Bia) e Eivor Martins Júnior pela amizade, carinho, respeito e discussões "críticas" sobre os nossos trabalhos. À Patrícia Soares Rogeri pela oportunidade de aprendizado, entusiasmo, amizade e o "braço" do dia a dia.Aos companheiros de Laboratório que sempre têm um motivo para inúmeras conversas e "gargalhadas":
In lymphocytes (LY), the well-documented antiproliferative effects of IFN-α are associated with inhibition of protein synthesis, decreased amino acid incorporation, and cell cycle arrest. However, the effects of this cytokine on the metabolism of glucose and glutamine in these cells have not been well investigated. Thus, mesenteric and spleen LY of male Wistar rats were cultured in the presence or absence of IFN-α, and the changes on glucose and glutamine metabolisms were investigated. The reduced proliferation of mesenteric LY was accompanied by a reduction in glucose total consumption (35%), aerobic glucose metabolism (55%), maximal activity of glucose-6-phosphate dehydrogenase (49%), citrate synthase activity (34%), total glutamine consumption (30%), aerobic glutamine consumption (20.3%) and glutaminase activity (56%). In LY isolated from spleen, IFNα also reduced the proliferation and impaired metabolism. These data demonstrate that in LY, the antiproliferative effects of IFNα are associated with a reduction in glucose and glutamine metabolisms.
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