EFFECT of EXERCISE ON GLUTAMINE SYNTHESIS and TRANSPORT in SKELETAL MUSCLE FROM RATS

EFFECT of EXERCISE ON GLUTAMINE SYNTHESIS and TRANSPORT in SKELETAL MUSCLE FROM RATS

Author Santos, Ronaldo V. T. dos Autor UNIFESP Google Scholar
Caperuto, Erico C. Google Scholar
Mello, Marco T. de Autor UNIFESP Google Scholar
Batista, Miguel L. Google Scholar
Rosa, Luis F. B. P. C. Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Universidade de São Paulo (USP)
Abstract P>Reductions in plasma glutamine are observed after prolonged exercise. Three hypotheses can explain such a decrease: (i) high demand by the liver and kidney; (ii) impaired release from muscles; and (iii) decreased synthesis in skeletal muscle. the present study investigated the effects of exercise on glutamine synthesis and transport in rat skeletal muscle.Rats were divided into three groups: (i) sedentary (SED; n = 12); (ii) rats killed 1 h after the last exercise bout (EX-1; n = 15); and (iii) rats killed 24 h after the last exercise bout (EX-24; n = 15). Rats in the trained groups swam 1 h/day, 5 days/week for 6 weeks with a load equivalent to 5.5% of their bodyweight.Plasma glutamine and insulin were lower and corticosterone was higher in EX-1 compared with SED rats (P < 0.05 and P < 0.01, respectively). Twenty-four hours after exercise (EX-24), plasma glutamine was restored to levels seen in SED rats, whereas insulin levels were higher (P < 0.001) and costicosterone levels were lower (P < 0.01) than in EX-1. in the soleus, ammonia levels were lower in EX-1 than in SED rats (P < 0.001). After 24 h, glutamine, glutamate and ammonia levels were lower in EX-24 than in SED and EX-1 rats (P < 0.001). Soleus glutamine synthetase (GS) activity was increased in EX-1 and was decreased in EX-24 compared with SED rats (both P < 0.001).The decrease in plasma glutamine concentration in EX-1 is not mediated by GS or glutamine transport in skeletal muscle. However, 24 h after exercise, lower GS may contribute to the decrease in glutamine concentration in muscle.
Keywords aerobic exercise
glutamine synthetase
glutamine transport
moderate exercise
soleus
Language English
Sponsor Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Grant number FAPESP: 01/13766-4
Date 2009-08-01
Published in Clinical and Experimental Pharmacology and Physiology. Malden: Wiley-Blackwell Publishing, Inc, v. 36, n. 8, p. 770-775, 2009.
ISSN 0305-1870 (Sherpa/Romeo, impact factor)
Publisher Wiley-Blackwell
Extent 770-775
Origin http://dx.doi.org/10.1111/j.1440-1681.2009.05146.x
Access rights Closed access
Type Article
Web of Science ID WOS:000268458200009
URI http://repositorio.unifesp.br/handle/11600/31734

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