title: Regulation of protein metabolism by glutamine: implications for nutrition and health.
abstract: Glutamine is the most abundant free alpha-amino acid in plasma and skeletal muscle. This nutrient plays an important role in regulating gene expression, protein turnover, anti-oxidative function, nutrient metabolism, immunity, and acid-base balance. Interestingly, intracellular and extracellular concentrations of glutamine exhibit marked reductions in response to infection, sepsis, severe burn, cancer, and other pathological factors. This raised an important question of whether glutamine may be a key mediator of muscle loss and negative nitrogen balance in critically ill and injured patients. Therefore, since the initial reports in late 1980s that glutamine could stimulate protein synthesis and inhibit proteolysis in rat skeletal muscle, there has been growing interest in the use of this functional amino acid to improve protein balance under various physiological and disease conditions. Although inconsistent results have appeared in the literature regarding a therapeutic role of glutamine in clinical medicine, a majority of studies indicate that supplementing appropriate doses of glutamine to enteral diets or parenteral solutions is beneficial for improving nitrogen balance in animals or humans with glutamine deficiency.
authors.affiliation: Ministry of Agriculture Key Laboratory of Animal Nutrition and Feed Science South China and Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Tianhe District, Wushan Road, Guangzhou, Guangdong, PR China. xi_pb@163.com
authors.forename: Pengbin
authors.initials: P
authors.lastname: Xi
authors.forename: Zongyong
authors.initials: Z
authors.lastname: Jiang
authors.forename: Chuntian
authors.initials: C
authors.lastname: Zheng
authors.forename: Yingcai
authors.initials: Y
authors.lastname: Lin
authors.forename: Guoyao
authors.initials: G
authors.lastname: Wu
mesh_terms: D000818:Animals; D002056:Burns / Q000503:physiopathology; D016638:Critical Illness; D019587:Dietary Supplements; D005973:Glutamine / Q000378:metabolism / Q000502:physiology* / Q000627:therapeutic use; D006801:Humans; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight; D044342:Malnutrition / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000378:metabolism; D020388:Muscular Dystrophy, Duchenne / Q000503:physiopathology; D009369:Neoplasms / Q000503:physiopathology; D052756:Nutritional Sciences; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D018805:Sepsis / Q000139:chemically induced / Q000503:physiopathology
chemical_list: D011506:Proteins; D005973:Glutamine