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napsgeargenezapharmateuticals domestic-supplypuritysourcelabsResearch Chemical SciencesUGFREAKeudomestic

glutathione, L-Glutamine, Glutamine Peptides?

thx9000

New member
Okay, I'm confused. The cool thing is that for the 18months I've been taking L-Glutamine (30g/day) I've only had one cold type infection, and it lasted all of 10 hours. I acutally timed it. I used to have pretty bad allergies and would get about two colds a year as well. Hardly ever get allergies either now...

But, now I read that Glutamine Peptides are much better choice. Who has the best product? I usually just see L-Glutamine not the peptides. My other question is, how do these two relate to glutathione?
 
Quoted

"Gastrointestinal surface protection and mucosa reconditioning
BACKGROUND: There is increasing evidence that preservation of the ecology of the gastrointestinal tract and the surface protection system„surfactants, mucus, and fiber„is important for the outcome in postoperative trauma patients, patients after bone marrow and liver transplantation, and patients with HIV or AIDS. Approximately 50% of the nourishment of the small intestine and > 80% of the nourishment of the large intestine comes from the lumen. This is especially deleterious to the large intestine. Within less than a week of intestinal starvation„even in the presence of intense parenteral nutrition„a mucosal atrophy is observed, promoting translocation of potentially pathogenic microorganisms. Enteral nutrition is crucial to the outcome in many of these conditions. If however, such a nutrition is based on simple carbohydrates, peptides, amino acids, or fatty acids, most of the nutrition administered will be absorbed in the upper gastrointestinal tract. Complex fibers and proteins can be regarded as nutrients especially destined to the lower gastrointestinal tract. They are fermented by the probiotic flora, normally colonizing the colonic mucosa, and the necessary nutrients: short-chain fatty acids and amino acids such as arginine and glutamine are produced at the level of the colonic mucosa. Careless antibiotic treatment reduces or eliminates this flora, induces local mucosal starvation, and makes the patients vulnerable to opportunistic infections and microbial intestinal translocation. METHODS AND RESULTS: In this review the role of the different ingredients of the surface protection system are discussed. A program to recondition the intestines, particularly the colonic mucosa by resupply of species-specific lactobacilli, surfactants, amino acids (especially glutamine), and oat fiber (beta-glucans) is suggested. Extensive experience in animal models and early experience in a patient population are summarized and discussed. Oat has been chosen as a substrate for fermentation because it contains 100 times more of membrane lipids (surfactants) than any other food, has a favorable amino acid pattern (rich in glutamine), and is rich in water-soluble, fermentable-fiber beta-glucans. More than 1000 isolates of human-specific lactobacilli have been studied. Some strains, especially those of plantarum type, have proven effective in colonizing the colonic mucosa, suppressing the potentially pathogenetic flora, and may have other probiotic effects as well. CONCLUSION: A totally new enteral formula has been designed based on probiotic bacteria and fiber and aimed at colonizing the intestinal mucosa with a local probiotic effect and fermentation of fiber. Bengmark S, Jeppsson B. Gastrointestinal surface protection and mucosa reconditioning. JPEN J Parenter Enteral Nutr 1995;19:410-415.

Glutamine: a conditionally essential nutrient or another nutritional puzzle
Malnutrition and infection are common among patients receiving bone marrow transplant. A recent randomized, double-blind study was conducted to determine whether the addition of glutamine to standard total parenteral nutrition solutions would improve nitrogen retention and reduce hospital morbidity in a group of 45 bone marrow transplant patients. The results showed improved nitrogen balance and reduced incidence of clinical infection in the glutamine-supplemented patients. Mobrahan S. Glutamine: a conditionally essential nutrient or another nutritional puzzle. Nutr Rev 1992;50:331-333.

Intestinal fuels: glutamine, short-chain fatty acids, and dietary fiber
In recent years, considerable research has focused on the physiologic effects and clinical uses of three dietary constituents thought to be trophic to the intestinal tract in human beings: glutamine, short-chain fatty acids (SCFAs), and dietary fiber. Glutamine is an important nitrogen-carrying amino acid that may be conditionally essential in certain disease states to support the gut barrier and immune function and overall protein use. Colonic irrigations with SCFA preparations have demonstrated enhanced healing of bowel tissue in animals and human beings. Dietary fiber supports bacterial SCFA production, normal stool output, and the gut barrier and immune function. However, optimal fiber doses for various medical conditions are not known, and the risk for gastrointestinal (GI) obstruction, diarrhea, gas, and bloating necessitates careful selection of patients and daily monitoring of fiber tolerance. A review of the current literature indicates that widespread use of glutamine and SCFA additives parenterally and enterally awaits further evidence of safety and efficacy in human beings, establishment of appropriate doses, and advances in formulation technology. Administration of dietary fiber to enhance bowel motility should be considered in long-term tube-fed patients with intact GI function and sufficient fluid tolerance to permit hydration of fiber. Industrywide agreement on fiber analysis methods and labeling standards (eg, fiber fermentability vs solubility) would facilitate selection of enteral products. To streamline studies and optimize research efforts in future clinical trials, standard criteria for evaluating GI function, diarrheagenic factors, and intestinal outcome variables should be established. Evans MA, Shronts EP. Intestinal fuels: glutamine, short-chain fatty acids, and dietary fiber. J Am Diet Assoc 1992;92:1239-1246,1249.

Safety of glutamine-enriched parenteral nutrient solutions in humans
To determine the safety of glutamine-enriched parenteral nutrition, seven normal volunteers were admitted to the Clinical Research Center for three 5-d study periods. The subjects received infusions of parenteral nutrients containing increasing doses of glutamine (0, 0.285, and 0.570 g.kg body wt-1.d-1) substituted for alanine and glycine. Each study period was preceded by greater than or equal to 2 wk of normal food intake. The diets were isocaloric (1.2X estimated basal metabolic rate) and isonitrogenous (1.5 g protein.kg-1.d-1) with nonprotein calories given as dextrose (38%) and fat emulsion (62%). The diets were all well tolerated and there were no untoward effects. Plasma glutamine concentrations increased significantly with glutamine administration but plateaued at concentrations approximately 25% above control values. Ammonia and glutamate, potentially toxic metabolites of glutamine, did not change significantly with glutamine enrichment. Nitrogen balance and hormonal concentrations were unchanged during the three dietary periods. Results of mental-status examinations and continuous performance testing were normal and unchanged throughout the three periods. Glutamine-enriched parenteral nutrient solutions are well tolerated with no associated signs of toxicity in normal humans. Lowe DK, Benfell K, Smith RJ, et al. Safety of glutamine-enriched parenteral nutrient solutions in humans. Am J Clin Nutr 1990;52:1101-1106

Antidepressive properties of L-glutamine. Preliminary report
A brief review of the literature on this topic, and a comparison of the results obtained in children by administrating L-glutamine with those obtained by other antidepressive drugs, is primarily presented. Having been tested in a sampler of 43 adults, affected by different forms of depressive, neurasthenic and dissociative illnesses, L-glutamine is indicated as owning clear anti-depressive properties, and the asthenia as target-symptom for its therapeutical use. Out of the endogenous depression with slowed-down motor activity, indeed good results were found in all cases, in which a vital level had been reached by the illness. Since L-glutamine is noticed being a precursor of GABA, this fact itself could explain its antidepressive properties, but it is necessary to remember that they very complex metabolism of the drug is still mostly unknown. Cocchi R. Antidepressive properties of L-glutamine. Preliminary report. Acta Psychiatr Belg 1976;76:658-666.

Glutamine-enriched diets support muscle glutamine metabolism without stimulating tumor growth
Glutamine is a principal fuel utilized by rapidly growing tumors. Advanced malignant disease results in muscle glutamine depletion and weight loss. Concern exists about providing dietary glutamine to the host with cancer since it may stimulate tumor growth. This study examined the effects of oral glutamine on muscle glutamine metabolism and tumor growth. Twenty-four rats with large sarcomas were pair fed a glutamine-enriched or glutamine-free elemental diet. Diets were isonitrogenous and isocaloric. After 6 days of feeding, the animals were anesthetized and arterial glutamine, hindquarter glutamine flux, muscle glutamine content, tumor weight, tumor DNA content, tumor glutaminase activity, and number of metaphase mitoses/high power field (HPF) in the tumor were determined. There was no difference in arterial glutamine between the two groups, but provision of a glutamine-enriched diet increased muscle glutamine content by 60% (2.31 +/- 0.21 mumole/g tissue vs 1.44 +/- 0.22 mumol/g tissue, P less than 0.05), which supported muscle glutamine release. There were no differences among tumor DNA content, tumor glutaminase activity, or tumor weight and there was no difference histologically in the number of metaphase mitoses/HPF. Glutamine-enriched oral diets may replete host glutamine stores and support muscle glutamine metabolism without stimulating tumor growth. Klimberg VS, Souba WW, Salloum RM, et al. Glutamine-enriched diets support muscle glutamine metabolism without stimulating tumor growth. J Surg Res 1990;48:319-323

Efficacy of glutamine-enriched enteral nutrition in an experimental model of mucosal ulcerative colitis
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. Fujita T ,Sakurai K. Efficacy of glutamine-enriched enteral nutrition in an experimental model of mucosal ulcerative colitis. Br J Surg 1995;82:749-751.

Effect of supplemental dietary glutamine on methotrexate concentrations in tumors
This study evaluated the effects of supplemental dietary glutamine (GLN) on methotrexate sodium concentrations in tumors and serum of sarcoma-bearing rats following the initiation of methotrexate. After randomization to a GLN diet (+GLN) or GLN-free diet (-GLN), tumor-bearing rats received 20 mg/kg of methotrexate sodium by intraperitoneal injection. The provision of supplemental GLN in the diet increased methotrexate concentrations in tumor tissues at 24 and 48 hours (38.0 +/- 0.20 nmol/g for the +GLN group vs 28.8 +/- 0.10 nmol/g for the -GLN group and 35.6 +/- 0.18 nmol/g for the +GLN group vs 32.5 +/- 0.16 nmol/g for the -GLN group, respectively). Arterial methotrexate levels were elevated only at 48 hours (0.147 +/- 0.007 microns/L for the +GLN group vs 0.120 +/- 0.006 microns/L for the -GLN group). Tumor morphometrics were not different between the groups but significantly greater tumor volume loss was seen even at 24 hours (-2.41 +/- 1.3 cm3 for the +GLN group vs -0.016 +/- 0.9 cm3 for the -GLN group). Tumor glutaminase activity was suppressed in both groups at 48 hours, but more so in the +GLN group (0.94 +/- 0.13 mumol/g per hour for the +GLN group vs 1.47 +/- 0.22 mumol/g per hour for the -GLN group). This study suggests that GLN may have therapeutic as well as nutritional benefit in oncology patients. Klimberg VS, Pappas AA, Nwokedi E, et al. Effect of supplemental dietary glutamine on methotrexate concentrations in tumors. Arch Surg 1992;127:1317-1320.

Glutamine preserves liver glutathione after lethal hepatic injury
Glutathione (GSH) is a major antioxidant that protects tissues from free radical injury. Glutamine augments host defenses and may be important in GSH synthesis. Acetaminophen toxicity causes hepatic GSH depletion and hepatic necrosis. The authors hypothesized that glutamine-supplemented nutrition would enhance liver GSH stores and diminish hepatic injury and death after acetaminophen overdose. Wistar rats received either a standard total parenteral nutrition (TPN) solution (STD) or an isocaloric, isonitrogenous glutamine-supplemented solution (GLN). On the 5th day of feeding, animals were given acetaminophen (400 mg/kg intraperitoneally) and then killed at various time points. Standard TPN solution animals had a rapid depletion of hepatic glutathione, whereas GLN animals were resistant to this drop and rapidly repleted hepatic GSH stores. Glutamine-supplemented animals maintained higher plasma glutamine concentrations, had lesser elevations in hepatic enzymes, and sustained significantly fewer complications compared with STD animals. The authors conclude that glutamine-supplemented nutrition preserves hepatic glutathione, protects the liver, and improves survival during acetaminophen toxicity. Glutamine may augment host defenses by enhancing antioxidant protection. Hong RW, Rounds JD, Helton WS, et al. Glutamine preserves liver glutathione after lethal hepatic injury. Ann Surg 1992;215:114-119.

The colonic epithelium in ulcerative colitis: an energy-deficiency disease?
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 utilisation of n-butyrate, the main respiratory fuel of the colonic mucosa, as well as utilisation of glucose and glutamine. In both acute and quiescent UC oxidation of butyrate to CO2 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 defect 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. Roediger WE. The colonic epithelium in ulcerative colitis: an energy-deficiency disease? Lancet 1980;2:712-715.

Luminal glutamine perfusion alters endotoxin-related changes in ileal permeability of the piglet
BACKGROUND: The objective of this study was to investigate whether luminal perfusion with glutamine or with oxygenated glutamine solutions prevents endotoxin-induced changes in mucosal permeability. METHODS: Three 15-cm segments of distal ileum were isolated in anesthetized 21-day-old piglets (n = 4) and perfused (50 mL/h) with RingerÍs lactate solution, RingerÍs lactate solution with 2% glutamine (wt/vol), glutamine, or glutamine purged with oxygen at 37 degrees C for 280 minutes. Plasma-to-lumen clearances of 51Cr-EDTA and urea were measured to assess mucosal permeability. At time 0 minutes, loading and maintenance IV infusions of markers were begun. Baseline permeabilities were obtained from time 60 to 80 minutes, and IV endotoxin (50 micrograms/kg) was introduced from time 80 to 140 minutes. RESULTS: Results are expressed as the ratio of the clearances of the two probes (CEDTA/CUREA). Permeability increased from baseline in loops perfused with RingerÍs lactate solution vs loops perfused with glutamine purged with oxygen and with glutamine alone (p <.01). Saturation with oxygen was without effect inasmuch as glutamine alone negated permeability increases. Intestinal myeloperoxidase activity did not differ with perfusate (p >.05). CONCLUSIONS: These data suggest that endotoxin-induced permeability changes can be prevented or delayed by the supply of luminal glutamine at the time of insult. Dugan ME, McBurney MI. Luminal glutamine perfusion alters endotoxin-related changes in ileal permeability of the piglet. JPEN J Parenter Enteral Nutr 1995;19:83-87.

Glutamine and alpha-ketoglutarate prevent the decrease in muscle free glutamine concentration and influence protein synthesis after total hip replacement
After surgical trauma, protein synthesis, as well as the concentration of free glutamine in muscle, decreases. Total parenteral nutrition (TPN) alone does not prevent the decrease of glutamine in muscle, but TPN supplemented with glutamine or its precursor, alpha-ketoglutarate, maintains amino acid concentration in muscle and preserves protein synthesis. The aim of this study was to characterize a human trauma model using patients undergoing total hip replacement, and furthermore to investigate whether glutamine or alpha-ketoglutarate alone without TPN can prevent the postoperative decrease in muscle free glutamine. Metabolically healthy patients undergoing total hip replacement were randomized into three groups. The control group (n = 13) received glucose 2 g/kg body weight (BW) during surgery and the first 24 postoperative hours. The glutamine group (n = 10) received glucose 2 g/kg BW and glutamine 0.28 g/kg BW, and the alpha-ketoglutarate group (n = 10) received glucose 2 g/kg BW and alpha-ketoglutarate 0.28 g/kg BW. Muscle biopsies were performed before surgery and 24 hours postoperatively. Free glutamine concentration in muscle decreased from 11.62 +/- 0.67 to 9.80 +/- 0.36 mmol/kg wet weight in the control group (P < .01), whereas it remained unchanged in both the glutamine group and alpha-ketoglutarate group. Protein synthesis, as reflected by the concentration of total ribosomes, decreased significantly in the control group, but not in glutamine and alpha-ketoglutarate groups. Polyribosome concentration decreased significantly in both the control and alpha-ketoglutarate groups. Total hip replacement can be used as a reproducible trauma model, with characteristic changes in the muscle amino acid pattern and protein synthesis 24 hours postoperatively. Glutamine, as well as cu-ketoglutarate, attenuated the decrease in free amino acids in muscle tissue after surgical trauma during hypocaloric infusion of glucose. Blomqvist BI, Hammarqvist F, von der Decken A, Wernerman J. Glutamine and alpha-ketoglutarate prevent the decrease in muscle free glutamine concentration and influence protein synthesis after total hip replacement. Metabolism 1995;44:1215-1222.

Glutamine prevents parenteral nutrition-induced increases in intestinal permeability
In addition to its role in absorbing nutrients, the intestinal mucosa provides an important barrier against toxins and bacteria in the bowel lumen. This study evaluated changes in rat jejunal permeability and histology after total parenteral nutrition (TPN) or TPN supplemented with glutamine. Lactulose and mannitol were used to measure jejunal permeability, and fixed stained histologic specimens were used to measure mucosal dimensions. After the insertion of central venous catheters, 18 male rats were randomly divided into three groups: CHOW, saline infusion with a standard laboratory rat diet ad libitum; TPN; and GLN, 2% L-glutamine-supplemented TPN. The TPN and GLN groups received isocaloric, isovolumic, and isonitrogenous feedings. After 7 days of infusion, a laparotomy was performed, and lactulose and mannitol were instilled into the lumen of a 25-cm ligated segment of jejunum. Urine was collected for 5 hours and assayed for lactulose, mannitol, and creatinine. The jejunum was harvested, and wet weight, villus height, mucosal thickness, and villus width were measured. Intestinal permeability to lactulose and the lactulose to mannitol ratio significantly increased after TPN compared with CHOW, and these effects were prevented with the addition of glutamine to the TPN solution. Jejunal villus height and mucosal thickness significantly decreased following TPN but were not significantly different from CHOW when glutamine was added to the TPN solution. These data suggest that TPN was associated with increased jejunal permeability and that glutamine, when added to the TPN solution, prevented this effect. In addition, glutamine reduced TPN-associated atrophy of the jejunum. Li J, Langkamp-Henken B, Suzuki K, Stahlgren LH. Glutamine prevents parenteral nutrition-induced increases in intestinal permeability. JPEN J Parenter Enteral Nutr 1994;18:303-307.

Glutamine enhances selectivity of chemotherapy through changes in glutathione metabolism
OBJECTIVE: Chemotherapy doses are limited by toxicity to normal tissues. Intravenous glutamine protects liver cells from oxidant injury by increasing intracellular glutathione (GSH) content. The authors hypothesized that supplemental oral glutamine (GLN) would increase the therapeutic index of methotrexate (MTX) by improving host tolerance through changes in glutathione metabolism. The authors examined the effects of oral glutamine on tumor and host glutathione metabolism and response to methotrexate. METHODS: Thirty-six 300-g Fischer 344 rats were implanted with fibrosarcomas. On day 21 after implantation, rats were randomized to receive isonitrogenous isocaloric diets containing 1 g/kg/day glutamine or glycine (GLY) by gavage. On day 23 after 2 days of prefeeding, rats were randomized to one of the following four groups receiving an intraperitoneal injection of methotrexate (20 mg/kg) or saline (CON): GLN+MTX, GLY+MTX, GLN-CON, or GLY-CON. On day 24, rats were killed and studied for arterial glutamine concentration, tumor volume, kidney and gut glutaminase activity, and glutathione content (tumor, gut, heart, liver, muscle, kidney, and lung). RESULTS: Provision of the glutamine-enriched diets to rats receiving MTX decreased tumor glutathione (2.38 +/- 0.17 in GLN+MTX vs. 2.92 +/- 0.20 in GLY+MTX, p < 0.05), whereas increasing or maintaining host glutathione stores (in gut, 2.60 +/- 0.28 in GLN+MTX vs. 1.93 +/- 0.18; in GLY+MTX, p < 0.05). Depressed glutathione levels in tumor cells increases susceptibility to chemotherapy. Significantly decreased glutathione content in tumor cells in the GLN+MTX group correlated with enhanced tumor volume loss (-0.8 +/- 1.0 mL in GLN+MTX vs. +9.5 +/- 2.0 mL in GLY+MTX, p < 0.05). CONCLUSION: These data suggest that oral glutamine supplementation will enhance the selectivity of antitumor drugs by protecting normal tissues from and possibly sensitizing tumor cells to chemotherapy treatment-related injury. Rouse K, Nwokedi E, Woodliff JE, et al. Glutamine enhances selectivity of chemotherapy through changes in glutathione metabolism.Ann Surg 1995;221:420-426.
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:D I love this stuff, and I know what you mean about keeping colds and so on away. It really does help me alot. I would be taking in about 50 grams a day but thats only due to such a high protein diet.

Vitamin C is also a good combination.
 
So it looks like L-Glutamine can help preserve glutathione levels in a stressed level. Which do you take though? The peptides, L-, or just Glutathione?
 
Well, it seems as if Iron Game has covered most everything. I will just say that I prefer the l-glutamine.
 
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