title: L-glutamine supplementations enhance liver glutamine-glutathione axis and heat shock factor-1 expression in endurance-exercise trained rats.
abstract: Liver L-glutamine is an important vehicle for the transport of ammonia and intermediary metabolism of amino acids between tissues, particularly under catabolic situations, such as high-intensity exercise. Hence, the aim of this study was to investigate the effects of oral supplementations with L-glutamine in its free or dipeptide forms (with L-alanine) on liver glutamine-glutathione (GSH) axis, and 70 kDa heat shock proteins (HSP70)/heat shock transcription factor 1 (HSF1) expressions. Adult male Wistar rats were 8-week trained (60 min/day, 5 days/week) on a treadmill. During the last 21 days, the animals were daily supplemented with 1 g of L-glutamine/kg body weight per day in either l-alanyl-L-glutamine dipeptide (DIP) form or a solution containing L-glutamine and l-alanine in their free forms (GLN+ALA) or water (controls). Exercise training increased cytosolic and nuclear HSF1 and HSP70 expression, as compared with sedentary animals. However, both DIP and GLN+ALA supplements enhanced HSF1 expression (in both cytosolic and nuclear fractions) in relation to exercised controls. Interestingly, HSF1 rises were not followed by enhanced HSP70 expression. DIP and GLN+ALA supplements increased plasma glutamine concentrations (by 62% and 59%, respectively) and glutamine to glutamate plasma ratio in relation to trained controls. This was in parallel with a decrease in plasma ammonium levels. Supplementations increased liver GSH (by 90%), attenuating the glutathione disulfide (GSSG) to GSH ratio, suggesting a redox state protection. In conclusion, oral administration with DIP and GLN+ALA supplements in endurance-trained rats improve liver glutamine-GSH axis and modulate HSF1 pathway.
authors.affiliation: Dept. of Food Science and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil.
authors.forename: Éder Ricardo
authors.initials: ÉR
authors.lastname: Petry
authors.forename: Vinicius Fernandes
authors.initials: VF
authors.lastname: Cruzat
authors.forename: Thiago Gomes
authors.initials: TG
authors.lastname: Heck
authors.forename: Paulo Ivo
authors.initials: PI
authors.lastname: Homem de Bittencourt
authors.forename: Julio
authors.initials: J
authors.lastname: Tirapegui
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects; D064751:Ammonium Compounds / Q000097:blood; D000818:Animals; D019587:Dietary Supplements; D005973:Glutamine / Q000097:blood / Q000378:metabolism / Q000494:pharmacology*; D005978:Glutathione / Q000378:metabolism*; D019803:Glutathione Disulfide / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D010805:Physical Conditioning, Animal; D010807:Physical Endurance / Q000502:physiology*; D017208:Rats, Wistar; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D064751:Ammonium Compounds; D006360:Heat-Shock Proteins; D014157:Transcription Factors; D005973:Glutamine; D005978:Glutathione; D019803:Glutathione Disulfide