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L-Glutamine 500 Grams
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ADP: $54.99
Price: $14.99
In Stock
Manufacturer: Supplement Direct
Manufacturer Part No: 734890103397
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500 Grams
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Supplement Facts
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Serving Size5Grams
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Servings Per Container100
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Amount Per Serving
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% Daily Value
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Pure L-Glutamine
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5g
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*
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* Daily Value not established
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* These statements have not been evaluated by
the Food and Drug Administration. This product is not intended to
diagnose, treat, cure, or prevent any disease.
GLUTAMINE
Glutamine homologues and derivatives: A limiting factor in current artificial nutrition?
Nutrition Clinique et Metabolisme (France), 1996, 10/1 (7- 17)
Glutamate,
aspartate, arginine and glutamine can represent a third to half of the
protein content in food and are the most amino acids rapidly cleared
from plasma after IV administration. However, their abundance is limited
in artificial nutrition. Along with alpha-ketoglutarate, ornithine,
asparagine, oxalo-acetate, they can be defined as glutamine homologues
and derivatives (GHD). Chemically, they share the same C4 and C5 carbon
skeletons. GHD are biochemically interchangeable, but their synthesis
from other substrates is quantitatively very limited and costly in
energy. Thus, muscular proteolysis becomes the main source of GHD in the
post-operative state. They play an important role in all processes
requiring rapid cell division: wound healing, preservation of gut
integrity, immune response, and growth in childhood. In addition, they
participate in detoxication and neurotransmission in the brain.
Experimental and clinical data suggest considering GHD content as a
decisive criterion when choosing an amino acid solution for parenteral
nutrition and probably also for enteral regimens. In human nutrition,
they could be at least as efficient as glutamine, whose presence in
parenteral mixtures is precluded by its poor stability. Enhanced supply
for GHD can be achieved with glutamine dipeptides or ornithine
alpha-ketoglutarate supplementation.
Regulation of protein turnover by glutamine in heat- shocked skeletal myotubes
Biochimica et Biophysica Acta - Molecular Cell Research (Netherlands), 1997, 1357/2 (234-242)
Skeletal
muscle accounts for approximately one-half of the protein pool in the
whole body. Regulation of protein turnover in skeletal muscle is
critical to protein homeostasis in the whole body. Glutamine has been
suggested to exert an anabolic effect on protein turnover in skeletal
muscle. In the present work, we characterized the effect of glutamine on
the rates of protein synthesis and degradation in cultured rat skeletal
myotubes under both normal and heat-stress conditions. We found that
glutamine has a stimulatory effect on the rate of protein synthesis in
stressed myotubes (21%, P < 0.05) but not in normal-cultured
myotubes. Glutamine shows a differential effect on the rate of
degradation of short- lived and long-lived proteins. In both
normal-cultured and stressed myotubes, the half-life of short-lived
proteins was not altered while the half-life of long-lived proteins
increased with increasing concentrations of glutamine in a
concentration-dependent manner. In normal-cultured myotubes, when
glutamine concentration increased from 0 to 15 mM, the half-life of
long-lived proteins increased 35% (P < 0.001) while in stressed
myotubes, it increased 27% (P < 0.001). We also found that glutamine
can significantly (P < 0.001) increase the levels of heat- shock
protein 70 (HSP70) in stressed myotubes, indicating that HSP70 may
participate in the mechanism underlying the effect of glutamine on
protein turnover. We conclude that in cultured skeletal myotubes the
stimulatory effect of glutamine on the rate of protein synthesis is
condition- dependent, and that the inhibitory effect of glutamine on the
rate of protein degradation occurs only on long-lived proteins.
Glutamine: From basic science to clinical applications
Nutrition (USA), 1996, 12/11-12 SUPPL. (S68-S70)
Glutamine
(Gln) has been one of the most intensively studied nutrients in the
field of nutrition support in recent years. Interest in provision of Gln
derives from animal studies in models of catabolic stress, primarily in
rats. Enteral or parenteral Gln supplementation improved organ function
and/or survival in most of these investigations. These studies have
also supported the concept that Gln is a critical nutrient for the gut
mucosa and immune cells. Recent molecular and protein chemistry studies
are beginning to define the basic mechanism involved in Gln action in
the gut, liver and other cells and organs. Double blind prospective
clinical investigations to date suggest that Gln-enriched parenteral or
enteral feedings are generally safe and effective in catabolic patients.
Intravenous Gln (either as the L-amino acid or as Gln-dipeptides) has
been shown to increase plasma Gln levels, exert protein anabolic
effects, improve gut structure and/or function and reduce important
indices of morbidity, including infection rates and length of hospital
stay in selected patients subgroups. Additional blinded studies of Gln
administration in catabolic patients and increasing clinical experience
with Gln-enriched nutrient products will determine whether routine Gln
supplementation should be given in nutrition support, and to whom. Taken
together, the data obtained over the pastdecade or so of intensive
research on Gln nutrition demonstrate that this amino acid is an
important dietary nutrient and is probably conditionally essential in
humans in certain catabolic conditions.
Effect of glutamine on leucine metabolism in humans
American Journal of Physiology ñ Endocrinology and Metabolism (USA), 1996, 271/4 34-4 (E748-E754)
The
aim of this study was to determine whether the putative protein
anabolic effect of glutamine 1) is mediated by increased protein
synthesis or decreased protein breakdown and 2) is specific to
glutamine. Seven healthy adults were administered 5-h intravenous
infusions of L- (1-14C) leucine in the postabsorptive state while
receiving in a randomized order an enteral infusion of saline on one day
or L-glutamine (800 micromol. kg-1. h-1, equivalent to 0.11 g N/kg) on
the other day. Seven additional subjects were studied using the same
protocol except they received isonitrogenous infusion of glycine. The
rates of leucine appearance (R (a Leu)), an index of protein
degradation, leucine oxidation (Ox (Leu)), and nonoxidative leucine
disposal (NOLD), an index of protein synthesis, were measured using the
14C specific activity of plasma alpha-ketoisocaproate and the excretion
rate of 14CO2 in breath. During glutamine infusion, plasma glutamine
concentration doubled (673 plus or minus 66 vs. 1,184 plus or minus 37
microM, P < 0.05), whereas R (a Leu) did not change (122 plus or
minus 9 vs. 122 plus or minus 7 micromol . kg-1 . h-1), Ox(Leu)
decreased (19 plus or minus 2 vs. 11 plus or minus 1 micromol kg-1 .
h-1, P < 0.01), and NOLD increased (103 plus or minus 8 vs. 111 plus
or minus 6 micromol . kg-1 . h-1, P < 0.01). During glycine infusion,
plasma glycine increased 14-fold (268 plus or minus 62 vs. 3,806 plus
or minus 546 microM, P < 0.01), but, in contrast to glutamine, R (a
Leu) (124 plus or minus 6 vs. 110 plus or minus 4 micromol . kg- 1 .
h-1, P = 0.02), Ox(Leu) (17 plus or minus 1 vs. 14 plus or minus 1
micromol . kg-1 . h- 1, P = 0.03), and NOLD (106 plus or minus 5 vs. 96
plus or minus 3 micromol . kg-1 . h-1, P < 0.65) all decreased. We
conclude that glutamine enteral infusion may exert its protein anabolic
effect by increasing protein synthesis, whereas an isonitrogenous amount
of glycine merely decreases protein turnover with only a small anabolic
effect resulting from a greater decrease in proteolysis than protein
synthesis.
Glutamine metabolism and transport in skeletal muscle and heart and their clinical relevance
Journal of Nutrition (USA), 1996, 126/4 SUPPL. (1142S- 1149S)
The
glutamine and glutamate transporters in skeletal muscle and heart
appear to play a role in control of the steady-state concentration of
amino acids in the intracellular space and, in the case of skeletal
muscle at least, in the rate of loss of glutamine to the plasma and to
other organs and tissues. This article reviews what is currently known
about transporter characteristics and mechanisms in skeletal muscle and
heart, the alterations in transport activity in pathophysiological
conditions and the implications for anabolic processes and cardiac
function of altering the availability of glutamine. The possibilities
that glutamine pool size is part of an osmotic signaling mechanism to
regulate whole body protein metabolism is discussed and evidence is
shown from work on cultured muscle cells. The possible uses of glutamine
in maintaining cardiac function perioperatively and in promoting
glycogen metabolism are discussed.
Glutamine: Effects on the immune system, protein metabolism and intestinal function
Wiener Klinische Wochenschrift (Austria), 1996, 108/21 (669-676)
Glutamine
is the most abundant free amino acid of the human body. In catabolic
stress situations such as after operations, trauma and during sepsis the
enhanced transport of glutamine to splanchnic organs and to blood cells
results in an intracellular depletion of glutamine in skeletal muscle.
Glutamine is an important metabolic substrate for cells cultivated under
in vitro conditions and is a precursor for purines, pyrimidines and
phospholipids. Increasing evidence suggests that glutamine is a crucial
substrate for immunocompetent cells. Glutamine depletion in the
cultivation medium decreases the mitogen-inducible proliferation of
lymphocytes, possibly by arresting the cells in the G0-G1 phase of the
cell cycle. Glutamine depletion in lymphocytes prevents the formation of
signals necessary for late activation. In monocytes glutamine
deprivation downregulates surface antigens responsible for antigen
preservation and phagocytosis. Glutamine is a precursor for the
synthesis of glutathionine and stimulates the formation of heat- shock
proteins. Moreover, there are suggestions that glutamine plays a crucial
role in osmotic regulation of cell volume and causes phosphorylation of
proteins, both of which may stimulate intracellular protein synthesis.
Experimental studies revealed that glutamine deficiency causes a
necrotising enterocolitis and increases the mortality of animals
subjected to bacterial stress. First clinical studies have demonstrated a
decrease in the incidence of infections and a shortening of the
hospital stay in patients after bone marrow transplantation by
supplementation with glutamine. In critically ill patients parenteral
glutamine reduced nitrogen loss and caused a reduction of the mortality
rate. In surgical patients glutamine evoked an improvement of several
immunological parameters. Moreover, glutamine exerted a trophic effect
on the intestinal mucosa, decreased the intestinal permeability and thus
may prevent the translocation of bacteria. In conclusion, glutamine is
an important metabolic substrate of rapidly proliferating cells,
influences the cellular Hydration State and has multiple effects on the
immune system, on intestinal function and on protein metabolism. In
several disease states glutamine may consequently, become an in
dispensable nutrient, which should be provided exogenously during
artificial nutrition.
The emerging role of glutamine as an indicator of exercise stress and overtraining
Sports Medicine (New Zealand), 1996, 21/2 (80-97)
Glutamine
is an amino acid essential for many important homeostatic functions and
for the optimal functioning of a number of tissues in the body,
particularly the immune system and the gut. However, during various
catabolic states, such as infection, surgery, trauma and acidosis,
glutamine homeostasis is placed under stress, and glutamine reserves,
particularly in the skeletal muscle, are depleted. With regard to
glutamine metabolism, exercise stress may be viewed in a similar light
to other catabolic stresses. Plasma glutamine responses to both
prolonged and high intensity exercises are characterised by increased
levels during exercise followed by significant decreases during the
post-exercise recovery period, with several hours of recovery required
for restoration of pre-exercise levels, depending on the intensity and
duration of exercise. If recovery between exercise bouts is inadequate,
the acute effects of exercise on plasma glutamine level may be
cumulative, since overload training has been shown to result in low
plasma glutamine levels requiring prolonged recovery. Athletes suffering
from the overtraining syndrome (OTS) appear to maintain low plasma
glutamine levels for months or years. All these observations have
important implications for organ functions in these athletes,
particularly with regard to the gut and the cells of the immune system,
which may be adversely affected. In conclusion, if methodological issues
are carefully considered, plasma glutamine level may be useful as an
indicator of an overtrained state.
The role of glutamine in nutrition in clinical practice
Arq Gastroenterol (BRAZIL) Apr-Jun 1996, 33 (2) p86-92
Nutritional
therapy using nutrients with pharmacological properties has been
intensively discussed in the recent literature. Among these nutrients,
glutamine has gained special attention. Glutamine is the most abundant
amino acid in the blood stream of the mammals and, besides it has been
considered a non-essential amino acid, glutamine is a non-dispensable
nutrient in catabolic states. In this situation, there are alterations
in its inter-organic flux, leading to lower plasmatic concentrations.
Glutamine is the main fuel to enterocytes and it has an important role
in the maintenance of intestinal structure and functions. Moreover,
supplementation with glutamine has proved to be beneficial to the
immunological system functions, improves nitrogen balance and
nutritional parameters in the post-operative period and lessens protein
loss in severe catabolic states. For these reasons, glutamine
enriched-diets must be considered in the nutritional support of many
diseases; new controlled, prospective and randomized studies will help
to define what group of patients can really benefit from glutamine
supplementation. (47 Refs.)
The metabolic role of glutamine
Minerva Gastroenterol Dietol (ITALY) Mar 1996, 42 (1) p17- 26
Glutamine
is a non-essential amino acid. Nevertheless it has to be considered a
conditionally essential amino acid for several metabolic reactions in
which it is involved. Glutamine is the most abundant amino acid in human
plasma and muscle. Because glutamine is highly unsteady, it was never
used for enteral and parenteral nutrition in the past. It appears to be a
unique amino acid for rapidly proliferating cells serving as a
preferred fuel compared to glucose. It seems to be essential for
cellular replication such as a nitrogen carrier between the tissues. A
deficiency state of glutamine causes morphology and functional changing
and negative nitrogen metabolism. The need for glutamine is particularly
high when metabolism is increased as in the critically ill (surgical
stress, sepsis, inflammatory states, fasten, burns) especially in the
tissues with a rapid cell turn-over. In these conditions the body
requirements of glutamine appear to exceed the individual's muscle
deposits (muscle is the most important place of synthesis and storage),
causing an increased synthesis with a high-energy waste and loss of
muscle mass. Glutamine is essential for bowel mucosa trophism and its
deficiency in all the catabolic states allows bacterial translocation.
In these cases feeding is not sufficient to restore basal conditions. At
present enteral or parenteral glutamine supplementations are of high
interest for the feeding of critically ill patients. (96 Refs.)
Glutamine and arginine metabolism in tumor bearing rats receiving total parenteral nutrition
Metabolism: Clinical and Experimental (USA), 1997, 46/4 (370-373)
Arginine
supplementation increases glutamine levels in muscle and plasma. Since
glutamine production is increased in catabolic states, these
observations prompted us to investigate whether the flux of arginine to
glutamine was increased in tumor-bearing (TB) rats, and we measured the
synthesis rate of glutamine from arginine in control versus TB rats
receiving standard total parenteral nutrition (TPN) solution. Male
Donryu rats (N = 36; body weight, 200 to 225 g) were divided into two
groups, control and TB rats. Yoshida sarcoma cells (1 x 106) were
inoculated into the back of the rats (n = 18) subcutaneously on day 0.
The rats were given free access to water and rat chow. On day 5, all
animals, including non-TB rats (n = 18), were catheterized at the
jugular vein and TPN was begun. On day 10, TPN solution containing
either U-14C-glutamine (2.0 microCi/h) or U-14C-arginine (2.0 microCi/h)
was infused as a 6-hour constant infusion. At the end of the isotope
infusion, plasma was collected to determine the glutamine production
rate in rats receiving U-14C-glutamine, and the ratio of specific
activity of glutamine to specific activity of arginine was measured in
rats receiving U- 14C-arginine. Only 2 g tumor caused a decrease in
glutamine levels and an increase in glutamine and arginine production.
The low flux rate of arginine to glutamine was observed in control rats
(Arg to Gln, 41.0 plus or minus 11.9 micromol/kg/h). On the other hand,
TB caused a significant increase in Arg to Gln compared with the control
(213.3 plus or minus 66.1 micromol/kg/h, P < .01 v control). An
increase in the flux rate of Arg to Gln was associated with an
enhancement in the ratio of specific activity of ornithine to specific
activity of arginine in TB rats (control 51.5% plus or minus 10.9% v
77.4% plus or minus 8.9%, P < .05). We conclude that (1) glutamine
and arginine metabolism is altered with very small tumors, (2) although
the flux of Arg to Gln was increased in TB and rats, the small increase
in Arg to Gln cannot explain the observed large increase in Gln
production.
Dietary modulation of amino acid transport in rat and human liver
Journal of Surgical Research (USA), 1996, 63/1 (263-268)
Specialized
diets enriched in the amino acids glutamine and arginine have been
shown to benefit surgical patients. In the liver, glutamine supports
glutathione biosynthesis, arginine regulates nitric oxide synthesis, and
both of these amino acids serve as precursors for ureagenesis,
gluconeogenesis, and acute phase protein synthesis. The effects of a
diet enriched with glutamine and arginine on hepatic plasma membrane
transport activity have not been studied in humans. We hypothesized that
feeding supradietary amounts of these nutrients would enhance the
activities of the specific carriers that mediate their transmembrane
transport in the liver. We fed surgical patients (n = 8) and rats (n =
6) one of three diets: a) a regular diet, b) an enteral liquid diet
containing arginine and glutamine, or c) an enteral diet supplemented
with pharmacologic amounts of glutamine and arginine. Diets were
isocaloric and were administered for 3 days. Hepatic plasma membrane
vesicles were prepared from rat liver and from human wedge biopsies
obtained at laparotomy. The transport of glutamine and arginine by rat
and human vesicles was assayed. Vesicle integrity and functionality were
verified by osmolarity plots, enzyme marker enrichments, and time
courses. Provision of both a standard enteral liquid diet and one
enriched with glutamine and arginine increased the activities of Systems
N (glutamine) and y' (arginine) in rat and human liver compared to a
control diet. The diet supplemented with glutamine and arginine was the
most effective in increasing transport activity. We conclude that the
liver responds to diets enriched with specific amino acids by increasing
membrane transport activity. This adaptive response provides essential
precursors for hepatocytes that may enhance hepatic synthetic functions
during catabolic states. This study provides insights into the
mechanisms by which enteral nutrition regulates nutrient transport at
the cellular level and may provide a biochemical rationale for the use
of formulas that areenriched with conditionally essential nutrients.
Development of an intravenous glutamine supply through dipeptide technology
Nutrition (USA), 1996, 12/11-12 SUPPL. (S76-S77)
Glutamine
is considered as semi-essential amino acid during catabolic stress. Due
to its chemical instability in aqueous solutions during heat
sterilization and long term storage, it could not be added to infusion
solutions so far. In contrast, the dipeptide glycl-L-glutamine exhibits
all properties needed for use as glutamine derivative in parenteral
nutrition. It is freely soluble in water and does not decompose during
heat sterilization. The peptide undergoes rapid enzymatic hydrolysis
after infusion. This results in perfect utilization. Glycyl-L- glutamine
is already produced in large amounts by chemical synthesis techniques.
Both chemical and optical purity of the dipeptide can be controlled by
modem chromatographic methods. Glamin, a newly developed complete amino
acid solution, contains 20 g of glutamine per liter in form of
glycyl-L-glutamine. Since no additional free glycine is added, no
imbalances are created by the amino-terminal amino acid of the peptide
structure.
Alanyl-glutamine prevents muscle atrophy and glutamine synthetase induction by glucocorticoids
American Journal of Physiology ñ Regulatory Integrative and Comparative Physiology (USA), 1996, 271/5 40-5 (R1165-R1172)
The
aims of this work were to establish whether glutamine infusion via
alanyl-glutamine dipeptide provides effective therapy against muscle
atrophy from glucocorticoids and whether the glucocorticoid induction of
glutamine synthetase (GS) is downregulated by dipeptide
supplementation. Rats were given hydrocortisone 21-acetate or the dosing
vehicle and were infused with alanyl-alanine (AA) or alanyl-glutamine
(AG) at the same concentrations and rates (1.15 micromol . min-1 . 100 g
body wt-1, 0.75 ml/h) for 7 days. Compared with AA infusion in hormone-
treated animals, AG infusion prevented total body and fast- twitch
muscle mass losses by over 70%. Glucocorticoid treatment did not reduce
muscle glutamine levels. Higher serum glutamine was found in the
AG-infused (1.72 plus or minus 0.28 micromol/ml) compared with the
AA-infused group (1.32 plus or minus 0.06 micromol/ml), but muscle
glutamine concentrations were not elevated by AG infusion. Following
glucocorticoid injections, GS enzyme activity was increased by two- to
threefold in plantaris, fast- twitch white (superficial quadriceps), and
fast-twitch red (deep quadriceps) muscle/fiber types of the AA group.
Similarly, GS mRNA was elevated by 3.3- to 4.1-fold in these same
muscles of hormone-treated, AA-infused rats. AG infusion diminished
glucocorticoid effects on GS enzyme activity to 52-65% and on GS mRNA to
31-37% of the values with AA infusion. These results provide firsthand
evidence of atrophy prevention from a catabolic state using glutamine in
dipeptide form. Despite higher serum and muscle alanine levels with AA
infusion than with AG infusion, alanine alone is not a sufficient
stimulus to counteract muscle atrophy. The AG-induced muscle sparing is
accompanied by diminished expression of a glucocorticoid-inducible gene
in skeletal muscle. However, glutamine regulation of GS appears complex
and may involve more regulators than muscle glutamine concentration
alone.
Tissue-specific regulation of glutamine synthetase
gene expression in acute pancreatitis is confirmed by using
interleukin-1 receptor knockout mice
Surgery (USA), 1996, 120/2 (255-264)
Background.
Acute pancreatitis causes a pronounced depletion of plasma and muscle
glutamine pools. In several other catabolic disease states expression of
the enzyme glutamine synthetase (GS) is induced in lung and muscle to
support glutamine secretion by these organs. The hormonal mediators of
GS induction have not been conclusively identified. We used mice
deficient for the expression of the type 1 interleukin-1 receptor
(IL-1R1 knockout mice) to investigate the expression of GS during acute
edematous pancreatitis.
Methods. Acute edematous pancreatitis
ways induced in adult male wild type and IL-1R1 knockout mice by means
of the intraperitoneal administration of cerulein, and their conditions
were monitored. Five organs, including lung, liver, gastrocnemius
muscle, spleen, and pancreas, were assayed for relative GS messenger RNA
(mRNA) content by Northern blotting. Results. The ultimate severity of
pancreatitis was reduced by IL-1R1 deficiency. GS mRNA levels increased
during progression of pancreatitis in lung, spleen, and muscle tissue
from each group. No consistent increase in GS mRNA level was observed in
liver. IL-1R1 deficiency did not affect GS mRNA expression in lung
tissue but consistently retarded GS induction in the spleens of knockout
animals. IL-1R deficiency altered the kinetics of GS induction in
muscle.
Conclusions. Cerulein-induced experimental pancreatitis
causes an induction in GS mRNA levels in a tissue-specific fashion.
IL-1R1 deficiency reduced the ultimate severity of the condition and
altered the induction of GS mRNA in the spleen and muscle.
Glutamine content of protein and peptide-based enteral products
Journal of Parenteral and Enteral Nutrition (USA), 1996, 20/4 (292-295)
Background:
Glutamine is a conditionally essential amino acid for patients with
severe catabolic illness, intestinal dysfunction, or immunodeficiency
syndromes. Glutamine is a natural component in many enteral
preparations, yet lacking methodology hampers its quantitative
determination in dietary products. Objective: The present study was
assigned to assess glutamine contents in selected enteral products by
using a newly developed method enabling the assessment of
protein/peptide bound glutamine.
Methods: Fourteen commercially
available enteral diets (10- protein based and 4 peptide based) were
investigated. After removal of interfering fat and carbohydrates, the
nitrogen content of the purified preparations was determined by
chemiluminescence and protein/peptide bound glutamine was assessed using
a three-step procedure; by using a novel prehydrolysis derivatization
technique with bis (1,1-trifluoroacetoxy) iodobe nzene, glutamine is
converted to acid stable diaminobutyric acid. The derivatives are
hydrolyzed with a new microwave technology, and subsequently the amino
acid composition is determined by reversed phase-high-performance liquid
chromatography after dansyl-chloride derivatization.
Results:
The content in the protein-based preparations varied between 5.2 and 8.1
g/16 g nitrogen. In the peptide- based products, considerably lower
glutamine contents were measured (1.3 to 5.6 g/16 g nitrogen).
Conclusion: In the present study, we report for the first time glutamine
contents in ready to use enteral products. The dally amount might be
satisfactory for healthy individuals but probably not sufficient for the
adequate support of the stressed patient. Reliable assessment of
glutamine in enteral formulae is a prerequisite to perform clinical
studies investigating glutamine requirements in the catabolic state.
Metabolic adaptation of terminal ileal mucosa after construction of an ileoanal pouch
Chapman
M.A.S.; Hutton M.; Grahn M.F.; Williams N.S. United Kingdom British
Journal of Surgery (United Kingdom), 1997, 84/1 (71-73)
Background
- The major nutrients for the large bowel and small bowel mucosa are,
respectively, butyrate and glutamine. The degree of mucosal adaptation
that may occur in response to changes in nutrient supply and faecal
stasis after the formation of an ileoanal pouch is poorly understood.
Method - The ability of ileal mucosal biopsies, from nine patients with
ulcerative colitis and from 18 with an ileoanal pouch, to oxidize
(14C)-glucose, glutamine and butyrate to carbon dioxide was quantified.
Results - Glucose, glutamine and butyrate were oxidized respectively at a
median of 12.5 (95 per cent confidence interval (4-22), 77 (34-207) and
194 (81-321) pmol microg- 1 h-1 by ileal mucosa and 12.9 (6-21), 35
(11-57) and 194 (73-737) pmol microg-1 h-1 by pouch mucosa. Conclusion -
Ileoanal pouch construction and subsequent bacterial colonization and
faecal stasis resulted in a significant (P < 0.05) reduction in the
mucosal ability to oxidize glutamine whereas there was no difference in
the rate of butyrate oxidation.
Nutrition and gastrointestinal disease
O'Keefe
S.J.D. Gastrointestinal Clinic, Groote Schuur Hospital, Observatory
7925, Cape Town, South Africa. Scandinavian Journal of Gastroenterology,
Supplement (Norway), 1996, 31/220 (52-59)
Nutrition and
intestinal function are intimately interrelated. The chief purpose of
the gut is to digest and absorb nutrients in order to maintain life.
Consequently, chronic gastrointestinal (GI) disease commonly results in
malnutrition and increased morbidity and mortality. For example, studies
have shown that 50-70% of adult patients with Crohn's disease were
weight- depleted and 75% of adolescents growth-retarded. On the other
hand, chronic malnutrition impairs digestive and absorptive function
because food and nutrients are not only the major trophic factors to the
gut but also provide the building blocks for digestive enzymes and
absorptive cells. For example, recent studies of ours have shown that a
weight loss of greater than 30% accompanying a variety of diseases was
associated with a reduction in pancreatic enzyme secretion of over 80%,
villus atrophy and impaired carbohydrate and fat absorption. Finally,
specific nutrients can induce disease, for example, gluten- sensitive
enteropathy, whilst dietary factors such as fibre, resistant starch,
short-chain fatty acids, glutamine and fish oils may prevent
gastrointestinal diseases such as diverticulitis, diversion colitis,
ulcerative colitis, colonic adenomatosis and colonic carcinoma. The role
of dietary antigens in the aetiology of Crohn's disease is
controversial, but controlled studies have suggested that elemental
diets may be as effective as corticosteroids in inducing a remission in
patients with acute Crohn's disease. In conclusion, nutrition has both a
supportive and therapeutic role in the management of chronic
gastrointestinal diseases. With the development of modern techniques of
nutritional support, the morbidity and mortality associated with chronic
GI disease can be reduced. On the other hand, dietary manipulation may
be used to treat or prevent specific GI disorders such as coeliac
disease, functional bowel disease, Crohn's disease and colonic
neoplasia. The future development of nutria-pharmaceuticals is
particularly attractive in view of their low cost and wide safety
margins.
Efficacy of glutamine-enriched enteral nutrition in an experimental model of mucosal ulcerative colitis
Fujita
T.; Sakurai K. First Department of Surgery, Jikei University School of
Medicine, 3-25-8 Nishishinbashi, Minato-ku, Tokyo 105 Japan British
Journal of Surgery (United Kingdom), 1995, 82/6 (749-751)
Intact
intestinal epithelium and associated lymphatic tissue act as body
defences against luminal toxins. This barrier may become threatened or
compromised in inflammatory bowel disease, leading to an increase in
mucosal permeability and subsequent translocation of endotoxins. The
effect of oral glutamine on gut mucosal ornithine decarboxylase activity
and on endotoxin levels in portal vein blood was studied in a
guinea-pig model of carrageenan- induced colitis. Despite failure to
show induction of ornithine decarboxylase activity by glutamine
administration, the mean endotoxin level of portal vein blood in
guinea-pigs fed a glutamine-enriched elemental diet was 25.3 pg/ml
compared with 71.2 pg/ml in animals given a standard elemental diet
(P<0.01). A glutamine- enriched elemental diet may be therapeutically
beneficial in patients with inflammatory bowel disease.
Ileal
and colonic epithelial metabolism in quiescent ulcerative colitis:
Increased glutamine metabolism in distal colon but no defect in butyrate
metabolism
Finnie I.A.; Taylor B.A.; Rhodes J.M. Department
of Medicine, University of Liverpool, PO Box 147, Liverpool L69 3BX
United Kingdom GUT (United Kingdom), 1993, 34/11 (1552-1558)
Previous
studies have shown that butyrate is an important energy source for the
distal colon, and that its metabolism may be defective in ulcerative
colitis (UC). A similar metabolic defect in the ileum might account for
the occurrence of 'pouchitis' in UC patients after colectomy. A method
has been developed that allows the measurement of metabolism in
ileocolonoscopic biopsy specimens, and this has been used to assess
butyrate and glutamine metabolism in quiescent UC and controls.
Preliminary experiments showed optimal metabolism of butyrate at 1
mmol/l. In controls glutamine metabolism was greater in the ascending
(mean (SD)) (4.9 (3.2) nmol/h/microg protein) than in the descending
colon (1.4 (0.7)) (p < 0.05, Mann-Whitney U test), but butyrate
metabolism was similar in the two regions (ascending 62.6 (44.2),
descending 51.5 (32.0)). Consequently ratios of butyrate/glutamine
metabolism were higher in the descending colon (20.6 (14.3)) than in the
ascending colon (14.3 (9.6)) (p < 0.05). In UC, rates of butyrate
metabolism were similar in the ascending (92.5 (58.3) nmol/h/microg
protein) and descending (93.3 (115)) colon, and these were not
significantly different from controls. In UC, glutamine metabolism was
similar in the ascending (6.2 (7.7) nmol/h/microg protein) and
descending colon (7.8 (7.9)); the metabolism in the descending colon was
significantly greater than in controls (p < 0.01). Butyrate (135
(56) nmol/h/microg protein) and glutamine (24.1 (16.2)) metabolism in
the ileum in UC, were not significantly different from control values
(butyrate 111 (57), glutamine 15.5 (15.6)). These results confirm that
there is regional variation of nutrient utilisation throughout the
colon, but they do not support the hypothesis that UC is caused by a
deficiency of butyrate metabolism.
Glutamine: Is it a conditionally required nutrient for the human gastrointestinal system?
Journal of the American College of Nutrition (USA), 1996, 15/3 (199-205)
Glutamine
is a nonessential amino acid that can be synthesized from glutamate and
glutamic acid by glutamine synthetase. It is the preferred fuel for the
rat small intestine. Animal studies have suggested both glutamine-
supplemented parenteral nutrition and enteral diets may prevent
bacterial translocation. This effect is thought to be modulated via the
preservation and augmentation of small bowel villus morphology,
intestinal permeability and intestinal immune function. The existing
data are less compelling in humans. It remains unclear what, if any,
intestinal deficits actually occur in humans during provision of
exclusive parenteral nutrition. Furthermore, the clinical significance
of these changes is largely undefined in humans. The existing data on
the use of parenteral and enteral glutamine for the purpose of
preserving intestinal morphology and function, and the prevention of
bacterial translocation in humans are reviewed. Pertinent animal data
are also described.
Induction of muscle glutamine synthetase gene expression during endotoxemia is adrenal gland dependent. (1)
Shock (UNITED STATES) May 1997, 7 (5) p332-8
Skeletal
muscle plays a crucial role in maintaining nitrogen homeostasis during
health and critical illness by exporting glutamine, the most abundant
amino acid in the blood. We hypothesized that induction of glutamine
synthetase (GS) expression, the principal enzyme of de novo glutamine
biosynthesis, in skeletal muscle after endotoxin administration was
adrenal gland dependent. We studied the expression of GS in normal and
adrenalectomized rats after intraperitoneal administration of
Escherichia coli lipopolysaccharide (LPS). Treatment of normal rats with
LPS resulted in a marked increase in GS mRNA that was dose and time
dependent, and preceded the increase in GS protein and specific
activity. The increase in muscle GS mRNA observed in normal rats in
response to LPS was abrogated in adrenalectomized rats at 3 h after high
dose LPS treatment and markedly attenuated at 5.5 h after low dose LPS
treatment. These and other studies implicate glucocorticoid hormones as a
key, but not exclusive, regulator of skeletal muscle GS expression
after a catabolic insult.
Induction of muscle glutamine synthetase gene expression during endotoxemia is adrenal gland dependent. (2)
Ann Surg (UNITED STATES) Apr 1997, 225 (4) p391-400
OBJECTIVE:
The objective of this study was to investigate the role of gut-derived
endotoxemia in postoperative glutamine (GLN) metabolism of bile
duct-ligated rats.
Summary
BACKGROUND DATA:
Postoperative complications in patients with obstructive jaundice are
associated with gut- derived endotoxemia. In experimental endotoxemia,
catabolic changes in GLN metabolism have been reported. Glutamine
balance is considered important in preventing postsurgical
complications.
METHODS: Male Wistar rats were treated orally
with the endotoxin binder cholestyramine (n = 24, 150 mg/day) or saline
(n = 24). On day 7, groups received a SHAM operation or a bile duct
ligation (BDL). On day 21, all rats were subjected to a laparotomy
followed 24 hours later by blood flow measurements and blood sampling.
Glutamine organ handling was determined for the gut, liver, and one
hindlimb. Intracellular GLN muscle concentrations were determined.
RESULTS:
Compared to the SHAM groups, BDL rats showed lower gut uptake of GLN
(28%, p < 0.05); a reversal of liver GLN release to an uptake (p <
0.05); higher GLN release from the hindlimb (p < 0.05); and lower
intracellular muscle GLN concentration (32%, p < 0.05).
Cholestyramine treatment in BDL rats maintained GLN organ handling and
muscle GLN concentrations at SHAM levels. CONCLUSIONS: Disturbances in
postoperative GLN metabolism in BDL rats can be prevented by gut
endotoxin restriction. Gut-derived endotoxemia after surgery in
obstructive jaundice dictates GLN metabolism.
Butyrate metabolism in the terminal ileal mucosa of patients with ulcerative colitis
Chapman
M.A.S.; Grahn M.F.; Hutton M.; Williams N.S. Department of Surgery,
University Hospital, Queen's Medical Centre, Nottingham NG7 2UH United
Kingdom British Journal of Surgery (United Kingdom), 1995, 82/1 (36-38)
The
rate of oxidation of butyrate, glutamine and glucose was investigated
in terminal ileal mucosal biopsy samples from nine patients with
ulcerative colitis undergoing restorative proctocolectomy and from 12
patients undergoing laparotomy for reasons other than ulcerative
colitis. Substrate oxidation was assayed using a radiolabelled isotope
technique. Butyrate was the preferred fuel substrate, followed by
glutamine and then glucose (median (95 per cent confidence interval) 567
(262- 894), 63 (35-123) and 8.1 (5.1-18) pmol microg-1 h-1
respectively; P < 0.01, Mann-Whitney U test) in normal terminal ileal
mucosa. The patients with ulcerative colitis had a significantly
reduced rate of butyrate oxidation compared with the control group (194
(81-321) versus 567 (262-894) pmol microg-1 h-1 P < 0.05). Normal
terminal ileal mucosa oxidized butyrate in greater quantities than
glucose and glutamine. Ulcerative colitic terminal ileal mucosa
exhibited an impaired rate of butyrate oxidation.
The colonic epithelium in ulcerative colitis: An energy- deficiency disease?
Roediger W.E.W. Nuffield Dept. Surg., Radcliffe Infirm, Univ. Oxford UNITED KINGDOM LANCET (ENGLAND), 1980, 2/8197 (712-715)
Suspensions
of colonocytes (isolated colonic epithelial cells) were prepared from
mucosa of the descending colon from 6 patients with quiescent ulcerative
colitis (UC), 4 with acute UC, and 7 control subjects. In each group
metabolic performance was investigated by assessing utilization of
n-butyrate, the main respiratory fuel of the colonic mucosa, as well as
utilization of glucose and glutamine. In both acute and quiescent UC
oxidation of butyrate to COsub 2 and ketones was significantly lower
than in the control tissues and the decrease correlated with the state
of the disease. Enhanced glucose and glutamine oxidation compensated for
decreased butyrate oxidation in UC, indicating that colonocytes in
colitis were not metabolically degenerate cells. Failure of butyrate
oxidation reflects a variable yet definite metabolic deficit in the
mucosa in UC. Diminished oxidation of butyrate can explain the
characteristic distribution of colitis along the colon, especially the
frequency of UC in the distal colon. It is suggested that failure of
fatty-acid (n-butyrate) oxidation in UC is an expression of an
energy-deficiency disease of the colonic mucosa.
Title
Glutamine
or glutamic acid effects on intestinal growth and disaccharidase
activity in infant piglets receiving total parenteral nutrition.
Author
Burrin DG; Shulman RJ; Storm MC; Reeds PJ
Source
JPEN J Parenter Enteral Nutr, 1991 May, 15:3, 262-6
Abstract
This
study was designed to measure the effect of free glutamine or glutamic
acid supplementation on small intestinal growth and disaccharidase
enzyme activity in 7-day-old miniature piglets. The piglets received one
of three total parenteral nutrition solutions exclusively for 7 days.
All three solutions were isonitrogenous and isocaloric, and glutamine or
glutamic acid was included at physiological levels (5% of the total
amino acid content) in two of the three solutions; the third (control)
contained neither glutamine nor glutamic acid. No differences were seen
between groups in plasma glutamine or glutamic acid concentrations.
Similarly, no effect was observed on small intestinal protein or DNA
content or on the specific activities of lactase, sucrase, or maltase.
These data demonstrate that in the healthy miniature piglet, parenteral
glutamine or glutamic acid supplemented at physiological doses does not
influence small intestinal growth and development.
Title
Effects of hypothyroidism on glucose and glutamine metabolism by the gut of the rat.
Author
Ardawi MS; Jalalah SM
Source
Clin Sci (Colch), 1991 Sep, 81:3, 347-55
Abstract
1.
The metabolism of glucose and glutamine was studied in the small
intestine and the colon of rats after 4-5 weeks of hypothyroidism. 2.
Hypothyroidism resulted in increases in the plasma concentrations of
ketone bodies (P less than 0.05), cholesterol (P less than 0.001) and
urea (P less than 0.001), but decreases in the plasma concentrations of
free fatty acids (P less than 0.05) and triacylglycerol (P less than
0.001). These changes were associated with decreases in the plasma
concentrations of total tri-iodothyronine, free tri-iodothyronine, total
thyroxine and free thyroxine. 3. Hypothyroidism decreased both the DNA
content (by 30.5%) and the protein content (by 23.6%) of intestinal
mucosa, with the protein/DNA ratio remaining unchanged. The villi in the
jejunum were shorter (P less than 0.05) and the crypt depth was
decreased by about 26.5% in hypothyroid rats. 4. Portal-drained visceral
blood flow showed no marked change in response to hypothyroidism, but
was accompanied by decreased rates of extraction of glucose, lactate and
glutamine and release of glutamate, alanine and ammonia. 5. Enterocytes
and colonocytes isolated from hypothyroid rats showed decreased rates
of utilization and metabolism of glucose and glutamine. 6. The maximal
activities of hexokinase (EC 2.7.1.1), 6-phosphofructokinase (EC
2.7.1.11), pyruvate kinase (EC 2.7.1.40), citrate synthase (EC
4.1.3.28), oxoglutarate dehydrogenase (EC 1.2.4.2) and
phosphate-dependent glutaminase (EC 3.5.1.2) were decreased in
intestinal mucosal scrapings from hypothyroid rats. Similar decreases
were obtained in colonic mucosal scrapings (except for citrate synthase
and oxoglutarate dehydrogenase) from hypothyroid rats.(Abstract TRUNCATED AT 250 WORDS)
Title
Protection from radiation injury by elemental diet: does added glutamine change the effect?
Author
McArdle AH
Source
Gut, 1994 Jan, 35:1 Suppl, S60-4
Abstract
The
feeding of a protein hydrolysate based 'elemental' diet supplemented
with added glutamine did not provide superior protection to the small
intestine of dogs subjected to therapeutic pelvic irradiation.
Comparison of diets with and without the added glutamine showed
significant protection of the intestine from radiation injury. Both
histological examination and electron microscopy showed lack of tissue
injury with both diets. The activity of the free radical generating
enzymes, scavengers, and antioxidants were similar in the intestinal
mucosa of dogs fed either diet. After radiation, however, the activity
of xanthine oxidase, superoxide dismutase, and glutathione peroxidase
were significantly (p <0.002) higher in the intestine of dogs fed
elemental diet without the added glutamine. If the activities of these
enzymes are important in the protection of the intestine from radiation
injury, then the addition of extra glutamine may provide no benefit.
Title
Inter-organ communication between intestine and liver in vivo and in vitro.
Author
Plauth M; Raible A; Gregor M; Hartmann F
Source
Semin Cell Biol, 1993 Jun, 4:3, 231-7
Abstract
The
maintenance of body homeostasis requires a finely tuned system of
interorgan communication. The intimate metabolic interrelation between
intestine and liver is characterized by the unique anatomic position of
both tissues using the portal vein as a private channel with the
pancreas in optimal position to modulate hepatic metabolism. Gut-derived
peptides (such as glucagon-like peptide-1) appear to be involved in the
process of liver regeneration by regulating the release of pancreatic
hormones (e.g. insulin). Extensive bowel resection or functional
exclusion of small intestine may lead to severe liver dysfunction and
even cirrhosis, which may be due to the lack of some intestine-derived
and as yet unknown factor(s). Here a close cooperation between small
intestinal mucosa and hepatocytes is demonstrated leading to the concept
of a metabolic gut-liver unit. This metabolic interaction forms a wide
spectrum ranging from the secretion of peptide hormones to changes in
(portal-venous) substrate availability or hepatocyte cell volume.
Further investigation and identification of the mechanisms of such
regulatory processes may be facilitated by combined perfusion of
isolated rat intestine and liver. Using this in vitro approach we could
demonstrate the presence of metabolic interorgan communication between
isolated perfused tissues independent of plasma borne hormones or
extrinsic neural control.
Title
Characteristics and mechanism of glutamine-dipeptide absorption in human intestine.
Author
Minami H; Morse EL; Adibi SA
Source
Gastroenterology, 1992 Jul, 103:1, 3-11
Abstract
Using
in vivo and in vitro techniques, the mechanism by which intestinal
mucosa obtains glutamine from luminal oligopeptides was investigated in
humans. The rate of hydrolysis by mucosal brush border membrane was more
than threefold greater for alanylglutamine than for glycylglutamine.
Despite this difference, rates of dipeptide and amino acid disappearance
during intestinal perfusion were greater from test solutions containing
glycylglutamine than alanylglutamine. Furthermore, rates of
intraluminal appearance of products of hydrolysis during the infusion of
two dipeptides were similar and less than 5% of the disappearance rate
of the parent dipeptide. In contrast to free glutamine, uptake of
peptide-bound glutamine by brush border membrane vesicles was not
inhibited by deletion of sodium or addition of free amino acids to the
incubation medium but was inhibited by other oligopeptides and
stimulated by a proton gradient. Inhibition constants for the saturable
uptake of glycylglutamine and alanylglutamine by vesicles were not
significantly different, suggesting similar affinities for the peptide
transporter. It is concluded that in human intestine the predominant
mechanism for assimilation of glutamine-dipeptides is absorption as
intact dipeptide rather than hydrolysis.
Title
Enteral nutrition as primary therapy in short bowel syndrome.
Author
Booth IW
Source
Gut, 1994 Jan, 35:1 Suppl, S69-72
Abstract
The
spectacular success of parenteral nutrition in supporting patients
during small intestinal adaptation after massive resection, tends to
obscure the prolonged periods often needed for such adaptation to take
place. After neonatal small intestinal resection for example, it may
take more than five years before adaptation is complete. There is
therefore a strong argument for examining ways in which adaptation can
be facilitated, in particular, by the addition of novel substrates to
enteral feeds. Pectin is completely fermented by colonic bacteria to
short chain fatty acids. In the rat, addition of pectin to enteral feeds
led to a more rapid adaptive response in both the small and large
intestine after massive small intestinal resection, although faecal
nitrogen losses were increased. In a similar rat model, the provision of
40% of non-protein energy as short chain triglycerides facilitated the
adaptive response in the jejunum, colon, and pancreas. The importance of
glutamine as a metabolic substrate for the small intestine makes it
another potential candidate and some, but not all animal studies, have
suggested a therapeutic effect: increasing the glutamine content of
feeds to 25% of total amino acids produced enhanced jejunal and ileal
hyperplasia, even on a hypocaloric feed, and an improved overall weight
gain. Studies in humans are very limited, but such promising results in
the experimental animal suggest that this is probably a fruitful area
for further study.
Title
Intestinal glutamine metabolism during critical illness: a surgical perspective.
Author
Herskowitz K; Souba WW
Address
Department of Surgery, University of Florida College of Medicine, Gainesville 32610.
Source
Nutrition, 1990 May, 6:3, 199-206
Abstract
In
critically ill surgical patients, various therapeutic maneuvers are
required to maintain a healthy gastrointestinal tract. Provision of
adequate amounts of glutamine to the gastrointestinal mucosa and
possibly to the gut-associated lymphatic tissue appears to be just one
of these necessary maneuvers. The concept that the intestine is inactive
after surgical stress merits reconsideration, as the intestinal tract
plays a central role in interorgan glutamine metabolism and is a key
regulator of nitrogen handling in this situation. Clinical studies to
examine the benefits of glutamine-enriched nutrition in hospitalized
patients are under way.
Title
Glutamine synthetase: a key enzyme for intestinal epithelial differentiation?
Author
Weiss MD; DeMarco V; Strauss DM; Samuelson DA; Lane ME; Neu J
Source
JPEN J Parenter Enteral Nutr, 1999 May, 23:3, 140-6
Abstract
BACKGROUND:
We have previously shown that glutamine synthetase protein and mRNA are
concentrated in the crypt region of the rat small intestine and that
the activity of this enzyme is highest around the time of weaning. This
anatomical location and time of peak activity are sites and periods of
active enterocyte differentiation. This led to our current hypothesis
that glutamine synthetase is important in the differentiation of
enterocytes.
METHODS: To test our hypothesis, we treated Caco-2 cells
with physiologic (0.6 mM) glutamine concentrations in cell culture
medium. The experimental group was treated with methionine sulfoximine,
an irreversible glutamine synthetase inhibitor, and the control group
with phosphate buffered saline. Three standard and well-defined markers
of intestinal differentiation-sucrase-isomaltase activity, microvillus
formation, and electrical impedance in transwell plates-were compared
between the two groups. RESULTS: The methionine-sulfoximine-inhibited
group was found to have lower sucrase-isomaltase activity, a lower
density of microvilli, and lower electrical impedance values over time
compared with the control group. CONCLUSION: The experimental group was
found to be less differentiated by all three markers of differentiation.
Therefore, glutamine synthetase is important for Caco-2 cell
differentiation.
Title
Effects of decreased glutamine supply on gut and liver metabolism in vivo in rats.
Author
Heeneman S; Deutz NE
Source
Clin Sci (Colch), 1993 Oct, 85:4, 437-44
Abstract
1.
It has recently been suggested that glutamine may be a conditionally
essential nutrient rather than a non-essential amino acid. Therefore,
administration of methionine sulphoximine was used to create a model of
decreased arterial glutamine concentrations for 4 days. Glutamine
consumption in portal-drained viscera and liver was measured after an
overnight fast by determining fluxes and intracellular concentrations in
normal rats, methionine sulphoximine-treated rats and pair-fed
controls. Moreover, fluxes and intracellular concentrations of several
other amino acids and ammonia and production of urea by the liver were
determined concomitantly. 2. Methionine sulphoximine treatment for 4
days resulted in a 50% decrease in arterial glutamine concentration.
Although the glutamine consumption and the intracellular glutamine
concentration of the intestine were reduced by 50% at day 4, no changes
in intestinal amino acid and ammonia metabolism were observed. 3. In the
liver, glutamine consumption was reduced and ammonia uptake was
increased, but urea synthesis was not changed. The decreased
intracellular glutamine, glutamate, aspartate and ammonia concentrations
coincided with a substantial reduction in liver branched-chain amino
acid production. 4. These results suggest that reduced intestinal
glutamine uptake does not induce marked changes in intestinal amino acid
metabolism. The decreased liver branched-chain amino acid production
suggests a reduction in the net liver protein degradation rate during
methionine sulphoximine treatment.
Title
Glutamine: is it a conditionally required nutrient for the human gastrointestinal system?[see
comments]
Author
Buchman AL
Source
J Am Coll Nutr, 1996 Jun, 15:3, 199-205
Abstract
Glutamine
is a nonessential amino acid which can be synthesized from glutamate
and glutamic acid by glutamine synthetase. It is the preferred fuel for
the rat small intestine.
Animal studies have suggested both
glutamine-supplemented parenteral nutrition and enteral diets may
prevent bacterial translocation. This effect is thought to be modulated
via the preservation and augmentation of small bowel villus morphology,
intestinal permeability and intestinal immune function. The existing
data are less compelling in humans. It remains unclear what, if any,
intestinal deficits actually occur in humans during provision
ofexclusive parental nutrition. Furthermore, the clinical significance
of these changes is largelyundefined in humans. The existing data on the
use of parenteral and enteral glutamine for thepurpose of preserving
intestinal morphology and function, and the prevention of
bacterialtranslocation in humans are reviewed. Pertinent animal data are
also described.
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Glutamine is the most abundant amino acid (protein building
block) in the body and is involved in more metabolic processes than any
other amino acid. Glutamine is converted to glucose when more glucose is
required by the body as an energy source. It serves as a source of fuel
for cells lining the intestines. It is also used by white blood cells
and is important to support immune function.
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Product Reviews
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