Glycyl-L-glutamine

Other Names

(2S)-5-amino-2-[(2-aminoacetyl)amino]-5-oxopentanoic acid(S)-5-Amino-2-(2-aminoacetamido)-5-oxopentanoic acid5-amino-2-(2-aminoacetamido)-5-oxopentanoic acid5-amino-2-[(2-amino-1-oxoethyl)amino]-5-oxopentanoic acidGlutamine, N2-glycyl-, L-Gly-GlnGly-Gln monohydrateGly-Gln-OHGly-L-Gln-OHGlycine-L-glutamineGlycyl-glutamineGlycyl-L-glutamine hydrateGlycyl-L-glutamine hydrate (1:1)Glycyl-L-glutamine monohydrateGlycyl-L-glutaminhydratGlycylglutamineH-Gly-Gln-OHH-Gly-Gln-OH MonohydrateL-Glutamine, glycyl-L-Glutamine, glycyl-, hydrate (1:1)L-Glutamine, N2-glycyl-N2-Glycyl-L-glutamineβ-Endorphin (30-31)β-Lipotropin (90-91)

Synopsis

Glycyl-L-Glutamine: A Comprehensive Reference

1. Identity and Chemical Characterization

Chemical Names and Identifiers

Glycyl-L-glutamine is also known by the synonyms glycylglutamine, Gly-Gln, glycyl-glutamine, and by its IUPAC name (S)-5-amino-2-(2-aminoacetamido)-5-oxopentanoic acid. Its CAS registry number is 13115-71-4. Its molecular formula is C₇H₁₃N₃O₄, and it is listed in PubChem with Compound ID (CID) 123913.

Glycyl-glutamine (Gly-Gln; β-endorphin₃₀₋₃₁) is an endogenous dipeptide synthesized from β-endorphin₁₋₃₁. It is classified as a dipeptide — a compound comprising two amino acids, glycine and L-glutamine, joined by a peptide (amide) bond. Glycyl-L-glutamine has a molecular weight of 203.22 daltons, with glutamine comprising approximately 72 percent of the total weight.

Natural Sources and Occurrence

The β-endorphin fragments β-endorphin(1–27) and β-endorphin(1–26) had previously been isolated from porcine and bovine pituitary, but the C-terminal dipeptide glycyl glutamine had not been reported previously. Its isolation from porcine pituitary was first described in 1983, and evidence for its presence in sheep brain stem was also presented at that time.

β-Endorphin₁₋₃₁ is extensively processed to Gly-Gln, as well as β-endorphin₁₋₂₆, β-endorphin₁₋₂₇, and their N-terminally acetylated analogs, in the brain, pituitary gland, and peripheral tissues that express the pro-opiomelanocortin (POMC) gene. Glutamine peptide, including glycyl-L-glutamine, is also widely present in humans, animals, plants, and microorganisms.

Common Forms and Preparations

Due to the chemical instability of free L-glutamine in aqueous solutions during heat sterilization and long-term storage, it could not be added to infusion solutions. In contrast, the dipeptide glycyl-L-glutamine exhibits all properties needed for use as a 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, resulting in efficient utilization.

Glycyl-L-glutamine is produced in large amounts by chemical synthesis techniques, and both chemical and optical purity of the dipeptide can be controlled by modern chromatographic methods. The commercial amino acid solution Glamin contains 20 g of glutamine per liter in the form of glycyl-L-glutamine.

Glutamine is usually administered either in its free form (isolated amino acid) or bonded with another amino acid in dipeptide form. Several glutamine dipeptides with potential health benefits have been described, such as l-glycyl-l-glutamine (Gly-Gln). In the research context, glycyl-L-glutamine is available as a purified powder for experimental use, as well as incorporated into parenteral nutrition solutions for clinical administration.

2. Traditional and Historical Use

Glycyl-L-glutamine is not a botanical extract or historically described remedy from any known traditional herbal medicine system. Its identity as a discrete molecule was first established only in the early 1980s through biochemical research. The seminal report was published by D.C. Parish and colleagues in Nature in November 1983. There is therefore no documented traditional use — in any culture or time period — of glycyl-L-glutamine as a defined compound or intentional preparation. The compound's use history is entirely scientific and clinical rather than traditional or ethnobotanical.

Historically, the broader concept of glutamine-rich protein foods (bone broths, fermented foods, wheat gluten) has featured in various traditional nutritional practices, but none of these preparations would have been understood to contain or deliver glycyl-L-glutamine specifically. The use of glycyl-L-glutamine as a component of parenteral nutrition solutions in critically ill and surgical patients emerged from research laboratories and hospital clinical practice beginning in the late 1980s and 1990s.

3. Key Constituents, Active Compounds, and Mechanisms of Action

Endogenous Origin: Biosynthesis from β-Endorphin

The primary mechanism of activation of intracellular prohormones involves proteolytic cleavage at sequences of consecutive basic residues. All known biologically active peptides derived from the prohormone of corticotropin and β-endorphin are excised initially by enzymes with this specificity. The C-terminal peptide β-endorphin(1–31) is generated by cleavage at a lysyl arginine sequence, and an additional cleavage can give rise to the related peptides β-endorphin(1–27) and β-endorphin(1–26). These derivatives are released by an endopeptidase that appears to catalyse cleavage on the carboxyl side of paired lysine residues, followed by the action of a carboxypeptidase B-like enzyme.

Glycyl-glutamine (Gly-Gln) is an endogenous dipeptide that is synthesized from β-endorphin post-translationally. By eliminating the opioid agonist potency of β-endorphin₁₋₃₁, post-translational processing apparently converts POMC neurons to a non-opioid phenotype.

Non-Opioid Nature and Opioid Modulation

Glycyl-glutamine and other post-translationally derived β-endorphin peptides display little or no affinity for opioid receptors. β-Endorphin₁₋₃₁ is extensively processed to Gly-Gln in the brain, pituitary gland, and peripheral tissues that express the POMC gene. Unlike β-endorphin₁₋₂₇, which is a relatively potent opioid receptor antagonist, Gly-Gln lacks significant opioid receptor binding activity.

Previous investigations have shown that Gly-Gln inhibits the cardiovascular and respiratory depression caused by morphine and β-endorphin₁₋₃₁, but it does not interfere with opioid analgesia. This concept is supported by reports that Gly-Gln inhibits some pharmacological effects produced by opioids: it attenuates the hypotension and respiratory depression caused by central β-endorphin₁₋₃₁ or morphine administration and inhibits the grooming response produced by β-endorphin₁₋₃₁.

Neuronal Inhibitory Activity

When applied ionophoretically to brain stem neurones in the rat, the dipeptide exhibited an inhibitory action on cell firing. This inhibitory neuronal effect was first documented by Parish et al. in 1983 and formed the basis for classifying glycyl-L-glutamine as an inhibitory neuropeptide.

Dopaminergic Mechanism in the Nucleus Accumbens

Research has shown that Gly-Gln prevents acquisition of morphine-conditioned place preference (a behavioral test of morphine reward) but does not interfere with morphine analgesia. The hypothesis tested was that Gly-Gln inhibits morphine reward by blocking morphine-induced dopamine efflux in the nucleus accumbens (NAc). This mechanism was investigated by microdialysis sampling of extracellular dopamine in the nucleus accumbens, pointing to a dopaminergic pathway as one route of Gly-Gln's action in modulating addictive behaviors.

Glutamine-Delivery Mechanism (Parenteral Nutrition Context)

In the parenteral nutrition context, glycyl-L-glutamine exhibits all properties needed for use as a glutamine derivative: it is freely soluble in water and stable to heat sterilization. After infusion, the peptide undergoes rapid enzymatic hydrolysis, resulting in efficient delivery of free glutamine to tissues. This hydrolysis, primarily by dipeptidase enzymes in the bloodstream and tissues, releases the constituent amino acids glycine and L-glutamine for direct utilization.

Neurotrophic Activity: Cholinergic System Effects

Glycyl-L-glutamine (Gly-Gln) increases the A12 and G4 forms of acetylcholinesterase (AcChoEase) in cultured embryonic rat skeletal muscle. Since Gly-Gln meets the criteria established for the neurotrophic factor in extracts of central nervous system/sciatic nerves that maintains AcChoEase and butyrylcholinesterase (BtChoEase) in the denervated cat superior cervical ganglion (SCG) in vivo, it was investigated in that system. Intracarotid infusion of glycyl-L-glutamine was shown to oppose the fall in acetylcholinesterase and butyrylcholinesterase contents of the cat SCG that otherwise follows preganglionic denervation, though the effect was demonstrable only on the vascularly remote left SCG, not on the directly infused right SCG — leading to the conclusion that a metabolite of Gly-Gln, formed in the blood, is an active neurotrophic factor.

Intestinal Barrier Mechanisms

Glutamine peptides, including glycyl-L-glutamine, play a crucial role in modulating intestinal barrier function and maintaining intestinal health. These biological effects are primarily mediated through the regulation of tight junction proteins, mucin secretion, inflammatory responses, and gut microbiota composition. Under normal physiological conditions, Gln is synthesized by glutamine synthetase and plays a crucial role in maintaining intestinal barrier function, regulating immune response, and maintaining antioxidant balance.

4. Scientific Evidence by Area of Use

4.1 Parenteral Nutrition in Critical Illness and Major Surgery

The potential benefit of parenteral glutamine (GLN) supplementation has been one of the most commonly studied nutritional interventions in the critical care setting. Heat-stable, soluble GLN dipeptides — including alanyl-GLN and glycyl-GLN — are rapidly hydrolyzed to free amino acids in plasma.

Systematic review and meta-analysis evidence: Early randomized controlled trials (RCTs) testing whether parenteral nutrition regimens that include glutamine dipeptides improve the outcomes of critically ill patients demonstrated convincingly that this regimen is associated with reduced mortality, infections, and hospital stays. However, several new RCTs on the same question challenged this, prompting a meta-analysis to resolve the controversy. Stringent eligibility criteria were used to select only RCTs that tested critically ill adult patients without hepatic and/or renal failure who were haemodynamically and metabolically stabilised and who were administered glutamine dipeptide strictly according to current clinical guidelines (via the parenteral route at 0.3–0.5 g/kg/day; max. 30% of the prescribed nitrogen supply) in combination with adequate nutrition. Fifteen RCTs (16 publications) fulfilled all selection criteria and involved 842 critically ill patients.

Postoperative immune function — glycyl-L-glutamine specifically: Surgery, trauma and inflammation reduce HLA-DR expression on monocytes, which is associated with increased susceptibility to infection and sepsis. Surgery decreases plasma glutamine levels, and the expression of HLA-DR on human monocytes in vitro is dependent on glutamine concentration in the culture medium, leading to the hypothesis that postoperative infusions of glutamine-dipeptides would prevent decreased HLA-DR expression on monocytes. In this randomized trial, thirty patients undergoing major abdominal surgery were allocated to receive either 1500 ml Vamin (control) or an isonitrogenic formulation containing Vamin and 500 ml glycyl-glutamine (35 g GLN; 0.5 g/kg BW) or alanyl-glutamine (35 g GLN; 0.5 g/kg BW) as a continuous infusion over 48 hours post-operatively. This was the first study comparing the dipeptides GLY-GLN and ALA-GLN in the postoperative setting. The GLY-GLN–induced preservation of HLA-DR on monocytes following surgery may prevent infectious complications in these patients.

In a subsequent clinical trial, a diminished postoperative induced immunosuppression was observed when patients received the dipeptide glycyl-glutamine (GLY-GLN) directly after surgery over a period of 48 hours. In these patients, a partial prevention of the decrease in HLA-DR expression on monocytes induced by surgery was observed.

Safety and dose escalation in polytrauma: A clinical trial (Weingartmann et al., 1996; Wien Klin Wochenschr 108(21):683–688) investigated the safety and efficacy of increasing dosages of glycyl-glutamine for total parenteral nutrition in polytrauma patients, cited in the PubMed literature as PMID 8956477.

Contrasting evidence: The REDOXS trial — a large-scale study in which renal failure and acute liver failure were, for the first time, not excluded and in which more than 30% of patients presented with baseline acute renal failure — showed, contrary to many previous traditional PN-based glutamine trials, that glutamine supplementation was associated with an increase in mortality. Thus, a key question remains as to whether parenteral GLN administered as a supplement to complete nutrition support is beneficial or harmful in this population. This finding underscores the importance of patient selection and the risks of extrapolating results across different clinical populations.

4.2 Acute Leukemia and Intensive Chemotherapy

The effects of parenteral glycyl-glutamine supplementation in patients with acute leukemia receiving intensive conventional chemotherapy were evaluated in a randomized, double-blind, controlled study that compared standard glutamine-free parenteral nutrition with a glycyl-glutamine-supplemented parenteral nutrition containing 20 g of glutamine. There was significantly faster neutrophil recovery in the group that received glutamine supplementation along with high-dose cytarabine chemotherapy as compared with those patients receiving cytarabine regimen alone. There was no significant difference in the recovery of CD4+ or CD8+ lymphocytes or monocyte activation between the two groups. The authors concluded that there is a possible role of glutamine in the stimulation of lymphocyte proliferation.

Evidence strength: This is a single randomized, double-blind, controlled clinical trial (Scheid et al., Nutrition 2004;20:249–254), thus a Level 2 study. It provides preliminary but controlled evidence for the specific benefit of glycyl-L-glutamine supplementation in the context of neutrophil recovery. Replication in larger trials would be needed to establish this benefit more firmly.

4.3 Cardiovascular Protection: Ischemia–Reperfusion Injury

The amino acids glycine and glutamine have been implicated in myocardial protection. One study aimed to determine whether protection could be enhanced using the dipeptide l-glycyl-l-glutamine in both young (8-week-old) and middle-aged (36-week-old) rat hearts representative of a more clinically relevant age group. Hearts were perfused in the Langendorff mode for 20 minutes, followed by 40 minutes of global normothermic ischaemia and 30 minutes of reperfusion. Gly-gln at concentrations of 0.5, 2, or 5 mM was added 10 minutes into baseline perfusion, was present throughout ischaemia, and was washed out after 10 minutes reperfusion. Reperfusion damage was assessed from lactate dehydrogenase release, and metabolic fitness from time to ischaemic contracture and accumulation of lactate and thiobarbituric acid reactive substances during ischaemia. At a concentration of 5 mM, glycyl-L-glutamine decreased reperfusion damage and increased the time to ischaemic contracture in isolated rat hearts in both age groups.

Evidence strength: This is animal (ex vivo, isolated rat heart) data only. There are no available human or clinical trials specifically examining glycyl-L-glutamine for cardiac ischemia-reperfusion protection. The evidence is preliminary and confined to experimental models.

4.4 Opioid-Related Effects: Tolerance, Dependence, and Withdrawal

Gly-Gln (β-endorphin₃₀₋₃₁) is an endogenous dipeptide synthesized from β-endorphin₁₋₃₁. Previous investigations have shown that Gly-Gln inhibits the cardiovascular and respiratory depression caused by morphine and β-endorphin₁₋₃₁, but it does not interfere with opioid analgesia. Studies tested whether Gly-Gln administration would influence morphine-induced conditioned place preference, tolerance, dependence, or withdrawal. Glycyl-glutamine at 1–100 nmol (intracerebroventricular) pretreatment significantly inhibited the acquisition of a conditioned place preference to morphine. Glycyl-L-glutamine (1–100 nmol) inhibits morphine-induced respiratory depression with no effect on morphine-induced analgesia in rats. It also inhibits acquisition of place preference, delays the development of tolerance, and reduces withdrawal intensity in morphine-conditioned rats.

A further study tested whether Gly-Gln, a nonopioid peptide derived from β-endorphin processing, prevents the cardiovascular depression induced by hemorrhage in conscious and anesthetized rats. Previously, Gly-Gln had been found to inhibit the hypotension and respiratory depression produced by β-endorphin and morphine but not to affect opioid antinociception. Hemorrhage significantly lowered arterial pressure in conscious rats (from 120.1 ± 2.9 to 56.2 ± 4.7 mmHg). Intracerebroventricular Gly-Gln (3, 10, or 30 nmol) pretreatment inhibited the fall in arterial pressure and increased heart rate significantly, in a dose-related response that was sustained during the 35-minute post-hemorrhage interval.

Evidence strength: All evidence in this area is from preclinical (rodent) studies involving intracerebroventricular (ICV) or intraperitoneal (IP) routes of administration, which are not directly translatable to human use. No human clinical trials on Gly-Gln for opioid modulation exist in the indexed literature.

4.5 Nicotine Addiction and Withdrawal

Glycyl-glutamine is an inhibitory dipeptide synthesized from β-endorphin₁₋₃₁. Studies that demonstrated Gly-Gln inhibits morphine conditioned place preference, tolerance, dependence, and withdrawal led researchers to test whether Gly-Gln's inhibitory activity extends to other rewarding drugs, specifically nicotine. In rats conditioned with nicotine (0.6 mg/kg, s.c.) for four days and tested on day five, glycyl-glutamine (100 nmol ICV) significantly inhibited both the acquisition and expression of a nicotine place preference. Gly-Gln prevents the acquisition and expression of a conditioned place preference to nicotine and blocks mecamylamine-induced conditioned place aversion in nicotine-dependent rats. Glycyl-glutamine thus inhibits the rewarding effects of nicotine and attenuates withdrawal in nicotine dependent rats.

Evidence strength: Entirely preclinical (rat) data; no human clinical studies are available in the indexed literature. Evidence must be regarded as highly preliminary.

4.6 Neurotrophic Effects on the Cholinergic System

Glycyl-L-glutamine (Gly-Gln) increases the A12 and G4 forms of acetylcholinesterase (AcChoEase) in cultured embryonic rat skeletal muscle. Since Gly-Gln meets the criteria established for the neurotrophic factor in extracts of central nervous system/sciatic nerves that maintains AcChoEase and butyrylcholinesterase (BtChoEase) in the denervated cat superior cervical ganglion (SCG) in vivo, it was investigated in that system. Solutions of Gly-Gln (10⁻⁷–10⁻³ M) in 0.9% NaCl were infused for 24 hours via the right common carotid artery of cats with preganglionically denervated SCG. Results suggested that the neurotrophic effect was produced by a metabolite of Gly-Gln. When glycine, L-glutamine, and glycyl-L-glutamic acid (Gly-Glu) were subsequently tested, glycine and L-glutamine were inactive; Gly-Glu (10⁻⁶–10⁻⁵ M) exerted a significantly positive neurotrophic effect at both ganglia.

Evidence strength: In vitro and animal (cat, rat) data only. No clinical studies in humans are available for this specific application.

4.7 Intestinal Barrier Function

Glutamine peptides can play a role in protecting the intestinal barrier by regulating tight junctions, mucin, inflammatory response, and intestinal flora. Results from a study indicated that glycyl-glutamine alleviated intestinal barrier damage caused by the weaning of piglets by regulating intestinal flora.

In a study of weaned piglets, 0.25%, 0.375%, or 0.50% Gly-Gln supplementation improved growth performance, enhanced serum immunity and antioxidant capacity, and improved the apparent digestibility of nutrients. Additionally, it upregulated the mRNA expression of jejunal tight junction proteins (ZO-1, Occludin, and Claudin-1).

A rat liver transplantation model found that enteral supplementation with glycyl-glutamine improves intestinal barrier function after liver transplantation (Jiang et al., Hepatobiliary & Pancreatic Diseases International 2011;10(4):380–385). More large-scale clinical studies are warranted to further validate the actual efficacy of glutamine peptides in humans.

Evidence strength: Predominately animal and cell-culture studies for glycyl-L-glutamine specifically; broader clinical evidence for the glutamine-delivered benefit exists but is largely from other delivery forms (free glutamine, alanyl-glutamine).

5. Body Systems and Health Areas of Association

Central Nervous System: When applied ionophoretically to brain stem neurones in the rat, the dipeptide exhibited an inhibitory action on cell firing. Gly-Gln is associated with modulation of opioid-related cardiovascular and respiratory depression and is linked to dopaminergic pathways in the nucleus accumbens relevant to reward and addiction.
Immune System: As the first study to compare GLY-GLN and ALA-GLN in the postoperative setting, the evidence suggests that GLY-GLN–induced preservation of HLA-DR on monocytes following surgery may prevent infectious complications in post-surgical patients.
Cardiovascular System: Glycyl-L-glutamine (gly-gln) is among the dipeptides identified as offering cardioprotection in experimental models.
Gastrointestinal Tract: Glycyl-L-glutamine plays a role in modulating intestinal barrier function and maintaining intestinal health, effects mediated through tight junction proteins, mucin secretion, inflammatory responses, and gut microbiota composition.
Neuromuscular/Cholinergic System: Glycyl-L-glutamine increases the A12 and G4 forms of acetylcholinesterase in cultured embryonic rat skeletal muscle.
Hematologic/Oncological: A randomized, double-blind, controlled study of glycyl-glutamine-dipeptide in the parenteral nutrition of patients with acute leukemia undergoing intensive chemotherapy found significantly faster neutrophil recovery in the group that received glutamine supplementation along with high-dose cytarabine.

6. Dosage Forms and Dosages Reported in Studies

Parenteral (Intravenous) Administration in Clinical Trials

Guidelines examined in meta-analysis specified parenteral administration at 0.3–0.5 g/kg/day, with a maximum of 30% of the prescribed nitrogen supply, in combination with adequate nutrition.
In the Spittler et al. postoperative immunosuppression trial, glycyl-glutamine was administered as 500 ml of solution providing 35 g GLN (0.5 g/kg body weight) as a continuous infusion over 48 hours post-operatively.
The commercial amino acid solution Glamin contains 20 g of glutamine per liter in the form of glycyl-L-glutamine.

Preclinical/Experimental Dosages (Animal Studies — Not Applicable to Humans)

Glycyl-L-glutamine at 1–100 nmol inhibited morphine-induced respiratory depression in rats (intracerebroventricular route).
Intracerebroventricular Gly-Gln at 3, 10, or 30 nmol inhibited the fall in arterial pressure and increased heart rate significantly in a hemorrhage model in conscious rats.
In the isolated rat heart ischemia-reperfusion model, concentrations of 0.5, 2, or 5 mM gly-gln were tested, with gly-gln present throughout ischaemia.
In the nicotine place preference model, rats were conditioned with nicotine (0.6 mg/kg, s.c.) and glycyl-glutamine (100 nmol, ICV) was used to inhibit place preference acquisition.
In the weaned piglet study, 0.25%, 0.375%, or 0.50% Gly-Gln supplementation in feed was evaluated.

7. Safety Considerations and Interactions

General Tolerability in Clinical Use

A clinical trial titled "Safety and efficacy of increasing dosages of glycyl-glutamine for total parenteral nutrition in polytrauma patients" (Weingartmann et al., Wien Klin Wochenschr 1996;108(21):683–688) specifically evaluated the safety profile of the dipeptide at escalating doses. In the broader context of parenteral glutamine dipeptides, no evidence of harm has been observed in studies conducted to date with glutamine supplementation; high-dose or parenteral glutamine (>0.25 to 0.30 g/kg/day IV or ≥30 g/day enterally) appears to demonstrate the greatest potential for benefit in hospitalized patients, and further clinical trials are warranted.

Absence of Effect on Opioid Analgesia and Baseline Physiological Function

When given alone to opiate-naïve animals, Gly-Gln has no discernable effect on respiration, cardiovascular function, or nociceptive response latencies. This is an important safety-relevant finding: glycyl-L-glutamine does not appear to independently suppress vital physiological functions.

Risk in Patients with Hepatic or Renal Failure

Meta-analysis criteria specifically excluded critically ill patients with hepatic and/or renal failure from the group expected to benefit from parenteral glutamine dipeptide supplementation. In the REDOXS trial, where renal failure was not excluded and more than 30% of patients presented with baseline acute renal failure, glutamine supplementation was surprisingly associated with an increase in mortality. This finding indicates that patients with renal or hepatic impairment represent a population in whom glutamine dipeptide supplementation carries particular risk.

Requirement for Hemodynamic and Metabolic Stability

Eligible patient populations for beneficial parenteral glutamine dipeptide supplementation in meta-analyses were those who were haemodynamically and metabolically stabilised. Administration to patients in ongoing shock was not included in the studied guidelines, reflecting a boundary of the evidence base.

Neurotrophic Metabolite: Glycyl-L-Glutamic Acid

Research in the cat superior cervical ganglion model concluded that a metabolite of Gly-Gln — formed in the blood — is an active neurotrophic factor. Glycyl-L-glutamic acid and L-glutamic acid were subsequently found to have a similar but less marked effect on cholinesterase maintenance in both SCG. This indicates that the in vivo activity of glycyl-L-glutamine is partly mediated by its metabolites following hydrolysis.

Stereospecificity

A cyclic Gly-Gln derivative (Cyclo(Gly-Gln), 100 nmol ICV or 25 mg/kg IP) blocked expression of nicotine place preference, but Gly-d-Gln (100 nmol ICV) was ineffective. This finding demonstrates that the biological activity of Gly-Gln is stereospecific: the L-configuration of the glutamine residue is required for activity. This underscores the importance of stereochemical purity in preparations of the compound.

References

Health Conditions

Health conditions that Glycyl-L-glutamine may help support.

No conditions available.

Body Systems

Body systems that Glycyl-L-glutamine may help support.

No body systems available.