title: Changes in peripheral blood mononuclear cells glutamine synthetase mRNA after exercise in healthy volunteers: exploring an alternative proposal for non hepatic ammonia metabolism.
abstract: BACKGROUND
  Glutamine synthetase (GS) plays a central role in the inter-organ metabolism of ammonia and hepatic encephalopathy. The main objective of the present work was to disclose the possible effect of exercise on GS mRNA expression in peripheral blood mononuclear cells (PBMC) within a group of healthy volunteers.
  
  
  METHODS
  PBMC were studied instead of skeletal muscle because of ethical concerns. Characterization of GS in lymphocytes was carried out by indirect immunofluorescence and Western blot. After a pilot trial, expression of GS mRNA in PBMC was assayed by serial measurements in healthy volunteers who had exercised on a treadmill, and on a control group who had not. Muscle mass was estimated by bioimpedance.
  
  
  RESULTS
  Cytoplasmic GS had a molecular weight of 44 kDa. Serial measurements of its mRNA demonstrated an increase in the treadmill (n = 29), but not in the control group (n = 13) (p < 0.05). Peak expression occurred at 1 h in males and at 6 h in females. There was a positive correlation between muscle mass and the increase of the enzyme mRNA after exercise.
  
  
  CONCLUSIONS
  Exercise can increase the expression of GS mRNA in PBMC in healthy volunteers. Based on these preliminary results and on well-established physiological concepts, a hypothesis for non-hepatic ammonia metabolism is conceived. In the future could become part of the treatment of low-grade hepatic encephalopathy.
authors.affiliation: Departmento de Gastroenterología, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, DF.
authors.forename: Andrés
authors.initials: A
authors.lastname: Duarte-Rojo
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Torres-Vega
authors.forename: Hugo
authors.initials: H
authors.lastname: Villamil-Ramírez
authors.forename: José
authors.initials: J
authors.lastname: Estradas
authors.forename: Aarón
authors.initials: A
authors.lastname: Domínguez-López
authors.forename: Fausto
authors.initials: F
authors.lastname: Sánchez-Muñoz
authors.forename: Arturo
authors.initials: A
authors.lastname: Orea-Tejeda
authors.forename: Lilia
authors.initials: L
authors.lastname: Castillo-Martínez
authors.forename: Angel
authors.initials: A
authors.lastname: Miliar-García
authors.forename: Ricardo Ulises
authors.initials: RU
authors.lastname: Macías-Rodríguez
authors.forename: Aldo
authors.initials: A
authors.lastname: Torre
mesh_terms: D000328:Adult; D000641:Ammonia / Q000378:metabolism*; D015444:Exercise / Q000502:physiology*; D005260:Female; D005974:Glutamate-Ammonia Ligase / Q000235:genetics*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000201:enzymology / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis
chemical_list: D012333:RNA, Messenger; D000641:Ammonia; D005974:Glutamate-Ammonia Ligase