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PubMed1996

Glutamine and alanine metabolism in NIDDM.

Gluconeogenesis is increased in NIDDM. We therefore examined the metabolism of glutamine and alanine, the most important gluconeogenic amino acids, in 14 postabsorptive NIDDM subjects and 18 nondiabetic volunteers using a combination of isotopic ([6-3H]glucose (20 microCi, 0.2 microCi/min), [U-14C]glutamine (20 microCi, 0.2 microCi/min), [3-13C]alanine (99% 13C, 2 mmol, 20 micromol/min), [ring-2H5]phenylalanine (99% 2H, 2 micromol/kg, 0.03 micromol x kg(-1) x min(-1)), and limb balance techniques. Alanine turnover (4.54 +/- 0.24 vs. 5.64 +/- 0.33 micromol x kg(-1) x min(-1)), de novo synthesis (3.00 +/- 0.25 vs. 4.01 +/- 0.33 micromol x kg(-1) x min(-1)), and conversion to glucose (1.02 +/- 0.09 vs. 1.56 +/- 0.17 micromol x kg(-1) x min(-1)) were increased in NIDDM subjects (all P < 0.01), while its forearm release (0.45 +/- 0.04 vs. 0.39 +/- 0.04 micromol x kg(-1) x min(-1)) was unaltered. Although glutamine turnover (4.81 +/- 0.23 vs. 4.40 +/- 0.31 micromol x kg(-1) x min(-1)) was unaltered in NIDDM, its conversion to glucose (0.57 +/- 0.04 vs. 1.08 +/- 0.10 micromol x kg(-1) x min(-1)) and to alanine (0.10 +/- 0.01 vs. 0.34 +/- 0.04 micromol x kg(-1) x min(-1)) (both P = 0.001) was increased while its oxidation (2.84 +/- 0.27 vs. 1.84 +/- 0.15 micromol x kg(-1) x min(-1), P = 0.03) and forearm release (0.77 +/- 0.05 vs. 0.62 +/- 0.09 micromol x kg(-1) x min(-1), P < 0.008) were both reduced. Our results thus demonstrate that there are substantial alterations of glutamine and alanine metabolism in NIDDM. Conversion of both amino acids to glucose and the proportion of their turnover used for gluconeogenesis are increased; release of both amino acids from tissues other than skeletal muscle seems to be increased. Finally, the reduction in glutamine oxidation, possibly the result of competition with glucose and free fatty acids as fuels, makes more glutamine available for gluconeogenesis without a change in its turnover.

Alanine↗

PubMed1989

Effects of monensin and pH on the production and utilization of pyro-glutamate, a novel product of ruminal glutamine deamination.

Pure cultures of monensin-sensitive ruminal bacteria were involved in both the production and utilization of pyro-glutamate (pyrrolidone carboxylic acid), a novel product of glutamine fermentation, but the effect of monensin on pyro-glutamate accumulation in mixed cultures had not been assessed. Mixed ruminal bacteria (n = 3) fermented glutamine (40 mM) at a rapid rate (63 nmol/[mg protein-min]) and there was a transient increase in pyro-glutamate (3 mM). Monensin (5 ppm) decreased the rate of glutamine fermentation 70% and greatly enhanced the conversion of glutamine to pyro-glutamate (50 vs 7%). Glutamate was fermented at nearly the same rate as glutamine, and monensin eliminated glutamate fermentation. Glutamate was never converted to pyro-glutamate. Trypticase, a pancreatic digest of casein, contained pyro-glutamate, and a significant fraction (30%) of its N was never converted to ammonia. Pyro-glutamate utilization was reduced by monensin and low pH (less than 6.0). Based on these in vitro observations, pyro-glutamate could be a significant end-product of glutamine degradation when animals are fed monensin.

Animals↗

PubMed2006

Pathways from glutamine to apoptosis.

It is fascinating that a relatively simple amino acid like glutamine is involved in such large variety of cellular reactions. Glutamine is required for nitrogen-stimulated proliferation in many cells, but glutamine stimulates not only the growth of cells but also the expression of surface antigens, the formation of cytokines, the synthesis of heat shock proteins and many more vital events. Among all of them, apoptosis is a recent but outstanding incorporation to the whole of phenomena regulated by this peculiar amino acid. Apoptosis is an important process in a wide number of biologic systems. Apoptotic signalling mechanisms implicated in response to glutamine deprivation are cell type-specific. In any case, new findings indicate that glutamine availability is strongly related to the induction of apoptosis, working both as a nutrient and as a signalling molecule, acting directly or indirectly on the pathways leading to programmed cell death. Following, we will describe as glutamine and the related species glutamate, glutathione and glucosamine can play important roles in the pathways leading to apoptosis.

Apoptosis↗

PubMed1995

Alteration of glutamine concentration in the vitreous humor in patients with proliferative vitreoretinopathy.

Using sensitive high performance liquid chromatography (HPLC), we measured free amino acid concentrations in the undiluted vitreous samples of patients who underwent pars plana vitrectomy for treatment of idiopathic preretinal macular fibrosis (PMF, n = 8), proliferative diabetic retinopathy (PDR, n = 12), or proliferative vitreoretinopathy (PVR, n = 15) to investigate the effect of vitreoretinal diseases on the concentrations of free amino acids in human vitreous. The most abundant amino acid was glutamine in all of three groups. Other major amino acids commonly found in the human vitreous samples were serine, alanine, arginine, valine, and lysine. Patients with PDR and PVR showed significantly lower concentrations of glutamine in vitreous (PDR: 655 +/- 230 nmoles/ml, PVR: 683 +/- 302 nmoles/ml) than those with PMF (PMF: 975 +/- 247 nmoles/ml; significance level, PDR: p < 0.01, PVR: p < 0.05). In addition, patients with grade D PVR showed significantly lower concentration of glutamine (357 +/- 117 nmoles/ml) than those with grade C PVR (802 +/- 256 nmoles/ml, p < 0.005), or PMF (p < 0.005). These results suggest two possible mechanisms for the alteration of intravitreal glutamine in the pathologic conditions. The first possibility is a reduced amount of supply of glutamine that is normally transported or released from surrounding tissues into vitreous humor. The second possibility is an increased amount of uptake and utilization of glutamine by cells within vitreous and pathologic tissues.

Adolescent↗

PubMedDate not supplied

[Nutritional importance of glutamine].

The aim of this paper is to review nutritional aspects about this amino acid. Glutamine is the most abundant amino acid in the body. It is a neutral glucogenic amino acid that can be synthesized in the body by a wide variety of tissues rich in glutamine syntetase. Glutamine may promote muscle protein synthesis. Furthermore, glutamine is the principal carrier of nitrogen in the body, as it comprises approximately 50% of the whole-body pool of free amino acid. It is considered to be a major fuels for many cells including enterocytes, reticulocytes, stimulated lymphocytes, fibroblast and malignant cells. These cells share the common characteristics of relative rapid growth rates, high glicolitic rates, relative poor glucose oxidative capacity, and high glutaminase activity. In some clinical conditions, however, like trauma and sepsis, glutamine concentrations in tissues is decreased. These may have serious consequences for the organism, such as decreased in protein synthesis and impairement of the barrier functions of the mucosa of the gastrointestinal tract, and thereby contributy to the development of sepsis in catabolic patients. Infusion of glutamine may have therapeutic value in such conditions.

Dipeptides↗

PubMed1998

[Glutamine--its metabolic role and possibilities for clinical use].

Glutamine has been the point of interest of many nutritional studies concerning parenteral and enteral nutrition. Advantages from glutamine support have been observed previously in animal models. It was shown that glutamine is the energy source for rapidly dividing cells e.g. immune cells, gut mucosa. Recent molecular and protein chemistry studies have begun to define metabolic mechanism of glutamine action, and clinical trials suggest its safe and positive influence on catabolic patients. Parenteral and enteral nutrition enriched with glutamine improves gut integrity and function, decreases infection rate and improves function of immune cells. However, the indications for glutamine enriched nutrition and appropriate protocol of administration need determination. Taken together the data suggest that this amino-acid is an important dietary nutrient and is probably conditionally essential in certain catabolic conditions.

Animals↗

PubMed1999

Effects of glutamine supplementation of an amino acid-based purified diet on intestinal mucosal integrity in cats with methotrexate-induced enteritis.

OBJECTIVE: To determine effects of glutamine-supplemented and glutamine-free amino acid-based purified diets, compared with a dry expanded diet, on intestinal structure and function in a model that used cats with methotrexate-induced enteritis. ANIMALS: 18 adult specific-pathogen-free cats. PROCEDURE: 12 cats were given intragastric feedings of an amino acid-based purified diet supplemented with glutamine (7% [wt:wt]) or an isonitrogenous amount of glycine and alanine; 6 cats consumed a dry expanded diet. After 21 days, cats received methotrexate (MTX; 11 mg/kg of body weight, IV). Intestinal permeability testing was performed immediately before and 66 hours after MTX administration. Celiotomy was performed 72 hours after MTX administration for aseptic removal of mesenteric lymph nodes, collection of full-thickness intestinal biopsy specimens, determination of intestinal cellular proliferation, and collection of aortic and portal venous blood samples for determination of arteriovenous amino acid concentrations across the intestine. RESULTS: Administration of MTX was associated with severe enterotoxicosis manifested as diarrhea (8/12 cats), vomiting (12/12), and positive results for bacterial culture of mesenteric lymph nodes (12/12) in cats receiving the purified diets, independent of glutamine supplementation. Diet did not affect villus tip length and villus surface area in the small intestine or cellular proliferation. Administration of MTX was associated with significantly increased intestinal permeability, which was not attenuated by glutamine supplementation. CONCLUSIONS: Feeding of a glutamine-supplemented amino acid-based purified diet was unable to preserve intestinal function in cats with MTX-induced enteritis. CLINICAL RELEVANCE: Intestinal morphologic alterations correlate poorly with intestinal function as measured by means of bacterial translocation and intestinal permeability.

Amino Acids↗

PubMed1999

Synthesis of vesicular GABA from glutamine involves TCA cycle metabolism in neocortical neurons.

In contrast to the classic concept of direct conversion of glutamine to gamma-aminobutyric acid (GABA; via glutamate), this process may involve alpha-ketoglutarate as an intermediary metabolite and tricarboxylic acid (TCA) cycle activity. To obtain information about a possible differential role of these pathways for the synthesis of cytosolic and vesicular GABA, cultured neocortical neurons were incubated in medium containing [U-(13)C]glucose (0.5 mM) and in some cases unlabeled glutamine (0.5 mM). Subsequently, the cells were "superfused" for investigation of the effect of depolarization by 55 mM K+. To make sure that depolarization by 55 mM K+ released only vesicular GABA, tiagabin, a nontransportable inhibitor of the plasma membrane GABA carriers, was included in the medium to prevent GABA release from the cytoplasmic pool by reversal of the carriers. The importance of the TCA cycle for conversion of the carbon skeleton of glutamine to GABA was evident from the effect of glutamine on the labeling pattern of GABA. Percentage of labeling by GABA released into the depolarizing medium was the same as that in the corresponding cell extracts and was unaffected by the presence of glutamine during incubation. Despite the existence of multiple forms of glutamate decarboxylase, compartmentation of glutamate pools, and functionally different compartments within neurons, there appears to be full equilibration between the vesicular and cytosolic pools of GABA. However, during depolarization, the newly synthesized pool of GABA from glutamine does not rapidly equilibrate with the vesicular pool.

Amino Acids↗

PubMed2001

Reduction of paclitaxel-induced peripheral neuropathy with glutamine.

PURPOSE: Dose-limiting toxicity of many newer chemotherapeutic agents is peripheral neuropathy. Prior attempts to reduce this side effect have been unsuccessful. We report on the possible successful reduction of peripheral neuropathy with glutamine administration after high-dose paclitaxel. EXPERIMENTAL DESIGN: Patients entered a high-dose chemotherapy protocol in which the first high-dose cycle was paclitaxel at 825 mg/m(2) given over 24 h. The first cohort of patients did not receive glutamine, and the second cohort of patients received glutamine at 10 g orally three times a day for 4 days starting 24 h after completion of paclitaxel. Neurological assessment was performed at baseline, and at least 2 weeks after paclitaxel, and consisted of a complete neurological exam and nerve conduction studies. RESULTS: There were paired pre- and post-paclitaxel evaluations on 33 patients who did not receive glutamine and 12 patients who did. The median interval between pre- and post-exams was 32 days. For patients who received glutamine, there was a statistically significant reduction in the severity of peripheral neuropathy as measured by development of moderate to severe dysesthesias and numbness in the fingers and toes (P < 0.05). The degree and incidence of motor weakness was reduced (56 versus 25%; P = 0.04) as well as deterioration in gait (85 versus 45%; P = 0.016) and interference with activities of daily living (85 versus 27%; P = 0.001). Moderate to severe paresthesias in the fingers and toes were also reduced (55 versus 42% and 64 versus 50%, respectively), although this value was not statistically significant. All of these toxicities were reversible over time. CONCLUSIONS: Glutamine may reduce the severity of peripheral neuropathy associated with high-dose paclitaxel; however, results from randomized, placebo-controlled clinical trials will be needed to fully assess its impact, if any. Trials are currently ongoing to assess its efficacy for standard-dose paclitaxel in breast cancer and other tumors for which peripheral neuropathy is the dose-limiting toxicity.

Activities of Daily Living↗

PubMed2001

Heterogeneity of transport systems for L-glutamine in mouse mammary gland.

The characteristics of the transport systems of L-glutamine in lactating mouse mammary gland have been studied. L-glutamine uptake was mediated by three Na+-dependent and one Na+-independent systems. The 2-(methylamino)isobutyric acid-sensitive component of Na+-dependent uptake exhibited the usual characteristics of system A. The other two Na+-dependent systems, which we have named BCI(-)-dependent and BCl(-)-independent, are the new systems identified. These are broad specificity systems and were discriminated on the basis of inhibition analysis, Cl- dependency and the effect of preloading mammary tissue with amino acids. While L-aspargine inhibited the uptake of L-glutamine via both these broad specificity systems, L-homoserine inhibited the uptake of L-glutamine via only BCl(-)-dependent system. The uptake of L-glutamine via the BCl(-)-independent system was upregulated by preloading mammary tissue with L-serine, while BCl(-)-dependent system was unaffected. The Na+-independent uptake of L-glutamine was inhibited by 2-aminobicyclo-(2,2,1)heptane carboxylic acid and other neutral amino acids, and identified as the system L.

Amino Acids, Cyclic↗

PubMed2002

[Parenteral glutamine does not improve the nutritional status in patients during high-dose chemotherapy and autologous peripheral stem cell transplantation].

BACKGROUND AND AIM: High-dose chemotherapy is aggressive treatment modality adversely affecting both energy/protein demands and oral intake/resorption of nutrients. Aminoacid glutamine is known for its' proteoanabolic effect and as an energy source for enterocytes and immune system. Nutritional parameters have been studied in a controlled, randomised, double-blinded trial of parenteral glutamine supplementation of autologous stem cell transplant patients. METHODS: Forty consecutive patients with haematological and solid cancer and multiple sclerosis were treated from 1999 to 2001 by high-dose chemotherapy with autologous stem cell transplantation. Patients were randomly assigned either for parenteral administration of 30 g of alanyl-glutamine dipeptide (Dipeptiven, Fresenius-Kabi) or isonitrogenous glutamine-free amino acid solution from day +1 to day +14 or to discharge from hospital. Patients were closely monitored from admission to day +100. Nutritional parameters included: oral dietary intake, body weight, body composition, energy expenditure, concentration of serum proteins and nitrogen balance. Parenteral nutrition in dose of 26.5 kcal/kg and 1 g of aminoacid/kg was given to patients who did not reach adequate oral intake for 5 days and withheld after three consecutive days of adequate intake. RESULTS: Nutritional assessment on admission differed according to the method used but no parameter of nutrition predicted the clinical course of treatment. Inadequate oral intake period lasted (mean +/- SD) 6.8 +/- 5.9 days, average length of stay being 17.5 +/- 3.9 days. Patients were unable to use sipping of enteral feed. Resting energy expenditure neither on admission nor in critical period differed from predicted value. Serum protein concentrations significantly decreased on discharge with normalisation as soon as to day +28, correlating inversely with changes in extracellular water content. Nitrogen urine loss was 10-16 g/day. Only 42.5% of patients were treated with parenteral nutrition. Cumulative nitrogen balance at day +9 was -30.7 +/- 24.1 g N. Body weight at day +28 significantly decreased (-2.94 +/- 4.4 kg), mostly consisting of loss of pure body cell mass. Glutamine supplementation did not improve any of the listed nutritional parameters. CONCLUSIONS: High-dose chemotherapy with autologous stem cell transplantation causes proteocatabolism of medium severity. Nutritional status of patients cannot be improved by the mode and dosage of parenteral glutamine used in our study. Optimal nutritional monitoring and treatment for this group of patients is suggested.

Adult↗

PubMed2003

Glutamine-enriched parenteral nutrition after autologous peripheral blood stem cell transplantation: effects on immune reconstitution and mucositis.

BACKGROUND AND OBJECTIVES: Glutamine (gln), a non-essential amino acid, has recently received increasing attention because it becomes essential during stress and catabolic states: glutamine seems to modulate immune function and to promote faster intestinal healing after chemotherapy. We designed two consecutive randomized clinical trials to evaluate the role of glutamine-enriched parenteral nutrition (GEPN) in patients with hematologic malignancies submitted to high dose chemotherapy and autologous peripheral blood stem cell transplantation (aPBSCT) or immunoselected CD34+ aPBSCT. DESIGN AND METHODS: In study1, the Gln group (12 patients) received total parenteral nutrition (TPN) enriched with glutamine 20 g from day +1 after aPBSCT, while the placebo group (15 patients) received TPN lacking in glutamine (placebo). In study2, the Gln group (10 patients) received TPN enriched with glutamine 13.46 g from day +1, while the placebo group (11 patients) received a placebo. RESULTS: In the first study, a lymphocyte count >0.5 109/L was achieved on day 16.5 in the Gln group and on day 29 in the placebo group (p=0.005); in the second study, the lymphocyte count >0.5 109/L was achieved on day 18 in the Gln group and on day 29 in the placebo group (p=0.009). Lymphocyte subset analysis showed an increase of CD3+ and CD4+ and normalization of the CD16+CD56+ subset. Furthermore patients receiving GEPN showed a decrease in the mucositis severity peak calculated by the DMS (daily mucositis score: sum of the daily score of signs and symptoms) (p=0.047). INTERPRETATION AND CONCLUSIONS: GEPN is safe and effective and improves lymphocyte recovery after aPBSCT; further studies are needed to assess the clinical benefits of such an approach in order to justify its economic impact.

Adolescent↗

PubMed1976

Alanine and glutamine synthesis and release from skeletal muscle. III. Dietary and hormonal regulation.

Alanine and glutamine formation and release were studied using the intact epitrochlaris preparation of rat skeletal muscle. Alanine release from skeletal muscle was increased by fasting (65%), cortisone (145%), thyroxine (200%), and diabetes (185%). Glutamine release was decreased by cortisone (37%) and diabetes (23%) but not significantly affected by fasting or thyroxine. Tissue levels of alanine were unchanged but tissue glutamine levels were markedly reduced (30 to 60%) in all treatment groups. Insulin added in vitro did not affect amino acid release even with preparations obtained from diabetic animals. Inhibition of glycolysis with 0.2 mM iodoacetate had no effect on the rate of alanine and glutamine formation in any treatment group. Pyruvate generation was increased by all treatments even in the presence of the inhibitor. Total skeletal muscle alanine, aspartate, and branched chain aminotransferase, glutamate dehydrogenase, and malic enzyme activities were not significantly altered in any treatment groups. The addition of 10 mM aspartate, cysteine, branched chain amino acids, and serine significantly increased alanine formation, whereas the maximal rate of glutamine formation in the presence of stimulating amino acids was reduced in each treatment groups--the most marked effects were noted with cortisone and diabetic preparations. Although accelerated muscle proteolysis is an important factor regulating alanine formation in skeletal muscle, the redirection of carbon flow from glutamine toward alanine formation observed in fasting, cortisone, thyroxine-treated, and diabetic rats, indicates that factors other than proteolysis also participate in the control of amino acid release from muscle.

Alanine↗

PubMedDate not supplied

Capillary electrophoresis with a diamine EOF modifier as an approach for glutamine dipeptide containing formulations.

Currently, glutamine is thought to be conditionally indispensable amino acid. However, the use of glutamine in clinical practice encounters serious problems related to its limited solubility and instability in water solutions. Therefore, glutamine-containing dipeptides, which have better solubility and stability in the solution, have been introduced into the medical practice. High concentration of L-alanyl-L-glutamine in the medicinal product and thermal sterilization during the manufacturing process are the reasons of many impurities formation--the products of deamidation, racemization, cyclization etc.. The purpose of the study was to develop a single step CE method that could be applied in the purity control of L-alanyl-L-glutamine containing parenteral infusions instead of three routinely used LC methods. After systematic optimization separation conditions were selected: 100 mM borate buffer at pH 8.5 with 0.4 mM diaminopropane as EOF modifier. The method developed allows the separation and determination of the main component and the related impurities. The results show that the method is suitable for quality control of glutamine dipeptide solutions offering some advantages over routinely used LC methods.

Amino Acids, Diamino↗

PubMedDate not supplied

Glutamine does not prevent paclitaxel-associated myalgias and arthralgias.

Myalgias and arthralgias are prominent toxicities associated with paclitaxel. Pursuant to pilot information suggesting that glutamine could markedly alleviate this toxicity, we developed a placebo-controlled, double-blind, randomized crossover trial to test this hypothesis. This trial studied 36 patients who had experienced myalgias/arthralgias related to a prior paclitaxel-containing regimen and who were then randomized to receive oral glutamine (10 grams three times a day, starting on the day of chemotherapy) x 5 days or an identical-appearing placebo. For the subsequent cycle of chemotherapy, patients were crossed over, again in a double-blind manner, to receive the alternative treatment. Patients recorded daily myalgia/arthralgia scores on numerical scales. Physicians recorded patient-reported myalgias/arthralgias using National Cancer Institute common toxicity criteria at baseline and after each course of therapy. The results of this study revealed that glutamine had no effect on the development or severity of paclitaxel-induced myalgias/arthralgias, as recorded either by the patients' daily logs or by physician-reported information. Glutamine was well tolerated, with no suggestion of more toxicity compared to placebo. Upon completion of the two cycles, patients were asked to indicate which of the two blinded courses they preferred. Of those patients indicating a preference, 29% preferred the glutamine cycle, compared with 33% who preferred the placebo cycle (P = 0.96). Thus this trial did not suggest any role for oral glutamine, compared with placebo, for preventing the development, or alleviating the severity, of paclitaxel-induced myalgias/arthralgias.

Administration, Oral↗

PubMed2004

[Effect of glutamine on the non-steroidal anti-inflammatory drug-induced bacterial translocation].

BACKGROUND/AIMS: NSAIDs induce gut damage throughout the entire gastrointestinal tract and bacterial translocation. The aim of this study was to examine if administration of glutamine was able to prevent the NSAID-induced gut damages and bacterial translocation in the animal models. METHODS: Rats were utilized into 5 groups; control group, diclofenac group, and diclofenac with glutamine 0.8, 1.6, and 3.2 g/kg/day group. The animals with glutamine were fed with L-glutamine for 4 days before diclofenac administration. Gut injury was induced by administration of a single dose of diclofenac (80 mg/kg orally). Intestinal permeability (24 hour urinary excretion of phenolsulfonphthalein), enteric aerobic bacterial counts, serum biochemical profiles and bacterial translocation to mesenteric lymph nodes, liver and spleen were measured. RESULTS: Diclofenac caused the increase in intestinal permeability, enteric bacterial count, enteric protein and albumin loss and bacterial translocation. Administration of glutamine reduced the increase in intestinal permeability, protein losing enteropathy, enteric bacterial overgrowth and bacterial translocation induced by diclofenac. CONCLUSIONS: Glutamine may have beneficial effects on NSAID-induced gut damage and bacterial translocation.

Animals↗

PubMed1992

Effects of oral supplementation of glutamine on small intestinal mucosal mass following resection.

Following massive small bowel resection, the remaining small bowel increases in mucosal weight, protein, deoxyribonucleic acid (DNA) content and absorptive function. Enteral nutrients are known to be important in stimulating this response. Recently, glutamine has been described as an essential fuel for the small intestinal mucosa and is thought to be trophic to the small bowel. We investigated if glutamine, when added to the diet in large quantities, might stimulate mucosal adaptation beyond that which normally occurs following physiologic feedings. Male Sprague-Dawley rats were placed on powdered rat chow supplemented with either 5% glutamine, 5% glycine or 5% glucose. After 4 days rats underwent 70% jejunoileal resection. Fourteen days after resection, protein, DNA and sucrase activity in the duodenum of the glutaminefed animals were all significantly lower than results from both the glycine and glucose groups. Duodenal mucosal weight was lower in the glutamine group than in the glycine group. In the ileum, DNA content was significantly lower for the glutamine group than the glycine group. These results suggest that high concentrations of glutamine in the diet can have negative effects on intestinal adaptation.

Adaptation, Physiological↗

PubMed2005

[Effect of glutamine on small intestinal repair in weanling rats after chronic diarrhea].

OBJECTIVE: To investigate the nutrient effect of glutamine on small intestinal repair in weanling rats after chronic diarrhea. METHODS: Forty 21-day-old wistar rats were randomly divided into five groups (8 in each). Animal model of chronic diarrhea was induced by a lactose enriched diet in the weanling Wistar rat, normal control group was fed with a standard semipurified diet, and after 14 days the rats in both groups were killed to test the establishment of the model. After the establishment of the model, the other groups were fed with the standard semipurified diet to recover for 7 days, and were randomly divided into three groups: non-intervention group, glutamine (Gln)-intervention group and control group. Glutamine concentrations in blood was detected by high-performance liquid chromatography (HPLC). Morphological changes including villus height and villus surface area of the jejunum were measured under a light microscope and electron microscope, expression of proliferating cell nuclear antigen (PCNA) as an index of cell proliferation was observed using immunohistochemical staining and image analysis. RESULTS: The diarrhea rate in model group was 100 percent, average diarrhea index was 1.16 +/- 0.06, but both diarrhea rate and average diarrhea index in control group were 0 (P < 0.01), which affirmed establishment of the model. There was significant decrease of body weight, plasma Gln concentration, villus height, villus surface area and expression of PCNA in non-intervened group compared with the control group (P < 0.01). There was still significant decrease of body weight, villus height and villus surface area in Gln-intervened group compared with control group (P < 0.01), but plasma Gln concentration and expression of PCNA in Gln-intervened group had recovered to normal (P > 0.05). And compared with non-intervened group, except for body weight (P > 0.05), plasma glutamine, villus height, villus surface area and expression of PCNA were all significantly increased in Gln-intervened group. CONCLUSION: Chronic diarrhea can induce malnutrition and reduce the villus height, villus surface area, expression of PCNA and plasm glutamine concentration. Oral glutamine could improve the proliferation of crypt cell and promote repair of intestinal mucosa after chronic diarrhea.

Animals↗