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PubMed1990

Induction of the nag regulon of Escherichia coli by N-acetylglucosamine and glucosamine: role of the cyclic AMP-catabolite activator protein complex in expression of the regulon.

The divergent nag regulon located at 15.5 min on the Escherichia coli map encodes genes necessary for growth on N-acetylglucosamine and glucosamine. Full induction of the regulon requires both the presence of N-acetylglucosamine and a functional cyclic AMP (cAMP)-catabolite activator protein (CAP) complex. Glucosamine produces a lower level of induction of the regulon. A nearly symmetric consensus CAP-binding site is located in the intergenic region between nagE (encoding EIINag) and nagB (encoding glucosamine-6-phosphate deaminase). Expression of both nagE and nagB genes is stimulated by cAMP-CAP, but the effect is more pronounced for nagE. In fact, very little expression of nagE is observed in the absence of cAMP-CAP, whereas 50% maximum expression of nagB is observed with N-acetylglucosamine in the absence of cAMP-CAP. Two mRNA 5' ends separated by about 100 nucleotides were located before nagB, and both seem to be similarly subject to N-acetylglucosamine induction and cAMP-CAP stimulation. To induce the regulon, N-acetylglucosamine or glucosamine must enter the cell, but the particular transport mechanism used is not important.

Acetylglucosamine↗

PubMed1976

The effects of glucosamine derivatives on the growth of cultivable Treponema.

The effects of glucosamine and its derivatives on the growth of Treponema phagedenis biotypes reiter and kazan 5 were studied to determine if these agents could act as growth stimulants for organisms of the genus Treptonema. Growth studies on the cultivable treponemes were conducted in culture tubes containing glucosamine, glucosamine derivatives, and (or) glucose and galactose in serum-based media. Glucosamine and N-phenylacetylglucosamine were definitely inhibitory to growth at the concentrations studied. N-acetylglucosamine (NAG) produced mixed effects.

Acetylglucosamine↗

PubMed1986

Anorexia induced in rat by D-glucosamine deoxidized at C-1.

The effects of D-glucosamine (2-amino-2-deoxy-D-glucose), an endogenous glucose analogue, and 1-deoxy-D-glucosamine on feeding behavior were clarified. Test solutions (24 mumol) were infused into the third cerebroventricle of the rat. Glucosamine induced a feeding episode within 30 min after infusion and then prolonged the ensuing postprandial intermeal interval for the first 4 h of the dark period, while glucose suppressed feeding by decreasing meal size. Ventricular injection of 1-deoxyglucosamine potently suppressed feeding in a dose-related manner by affecting all meal parameters, and oral administration of 2,400 mumol also induced anorexia. Changes in activity of glucose-sensitive neurons in the lateral hypothalamus and glucoreceptor neurons in the ventromedial hypothalamus after electrophoretic application of glucosamine and 1-deoxyglucosamine were compatible with behavior changes. The results indicate that replacement of a hydroxyl group by an amino group at C-2 of the glucose molecule affects feeding behavior and deoxidation of C-1 potently induces anorexia.

Administration, Oral↗

PubMed2004

Glucosamine-induced endoplasmic reticulum stress promotes ApoB100 degradation: evidence for Grp78-mediated targeting to proteasomal degradation.

OBJECTIVE: To investigate the role of glucosamine-mediated endoplasmic reticulum (ER) stress and Grp78 (BiP) in the intracellular degradation of apolipoprotein B100 (apoB100) in cultured hepatocytes. METHODS AND RESULTS: Glucosamine treatment (2.5 to 10 mmol/L) of HepG2 cells increased levels of the ER chaperones, 78-kDa glucose-regulated protein (Grp78) and Grp94, in a dose-dependent manner and led to significant decreases in both cellular and secreted apoB100 by up to 97% (P<0.01). In contrast, no changes were observed in ER resident (ER60, PTP-1B) or secretory (albumin, apoE) control proteins. Glucosamine-induced apoB degradation was similarly observed in primary hamster hepatocytes and McA-RH7777 cells. Glucosamine treatment led to reduced tranlocational efficiency of apoB100 in the ER and enhanced its ubiquitination and proteasomal degradation. Adenoviral overexpression of Grp78 also led to significantly decreased levels of newly synthesized apoB100 in a dose-dependent manner (P<0.01). Grp78-induced downregulation of apoB100 was sensitive to inhibition by the proteasome inhibitor, lactacystin, but not lysosomal protease inhibitors, E64 and leupeptin, suggesting that overexpression of Grp78 selectively induced proteasomal degradation of apoB100. CONCLUSIONS: These findings suggest that binding and retention by Grp78 may play a critical role in proteasomal targeting and the ER quality-control of misfolded apoB. Interaction with core lipoprotein lipids may facilitate apoB transport out of the ER by reducing Grp78-mediated ER retention.

Adenoviridae↗

PubMed2026

Glucosamine links hyperglycemia to mTORC1 activation and glucose toxicity in diabetes.

Hyperglycemia is a principal driver of β cell failure and multiple-organ complications in diabetes. Chronic exposure to hyperglycemia overstimulates mTORC1, disrupting glucose metabolism and promoting ER stress, oxidative stress, and inflammation; however, the upstream metabolic signal(s) linking glucose to mTORC1 activation remains unclear. Here, we identified glucosamine as a key metabolite connecting elevated glucose to mTORC1 signaling in pancreatic islets and kidney, both major targets of hyperglycemic damage. Using 13C6-glucose metabolic labeling in diabetic rodents treated with or without the SGLT2 inhibitor dapagliflozin or insulin, combined with targeted metabolomics and metabolic flux analysis, we found that tissue glucose concentrations strongly correlated with glucosamine. A similar correlation with plasma glucose was conserved in humans with or without type 2 diabetes, and inversely associated with β cell function. In vitro, low-dose glucosamine stimulated mTORC1 in islets and kidney proximal tubule cells in an O-GlcNAcylation-dependent manner. Broad phosphoproteomics and transcriptomics analyses in β cells showed that glucosamine activated mTORC1-regulating pathways, induced oxidative stress, ER stress, and dedifferentiation. Genetic inhibition of β cell mTORC1 via heterozygous Raptor knockout, as well as pharmacologic inhibition of the glucosamine/mTORC1 axis through SGLT2 inhibition, alleviated β cell stress, improved glycemic control, and restored β cell function. These findings identified the glucosamine/mTORC1 pathway as an important mediator of β cell and kidney dysfunction in diabetes.

Animals↗

PubMed1980

Double-blind clinical evaluation of oral glucosamine sulphate in the basic treatment of osteoarthrosis.

The efficacy and tolerance of oral glucosamine sulphate were tested against placebo in a prospective double-blind trial in 20 out-patients with established osteoarthrosis. Two capsules of either glucosaminene sulphate (250 mg) or placebo were administered 3-times daily over a period of 6 to 8 weeks. Articular pain, joint tenderness and restricted movement were semi-quantitatively scored 1 to 4 every 3 days, and individually averaged over the treatment period (overall composite score). Possible side-reactions were similarly scored upon positive questioning of the patients. Haematology, erythrocyte sedimentation rate, urine analysis and X-rays were recorded before and after treatment. Significant alleviation of symptoms was associated with the use of the active drug at the prescribed dose. Similarly, patients given glucosamine sulphate experienced earlier alleviation of symptoms compared with those who had placebo. The use of glucosamine sulphate also resulted in a significantly larger proportion of patients who experienced lessening or disappearance of symptoms within the trial period. No adverse reactions were reported by the patients treated with glucosamine, and no variation in laboratory tests was recorded.

Aged↗

PubMed1998

A carbon-centered radical as a reaction species in the DNA strand-breakage by D-glucosamine.

Electron spin resonance(ESR) studies using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and sodium 3,5-dibromo-4-nitrosobenzensulfonate (DBNBS) as a spin-trapping agent revealed the formation of both hydroxyl and carbon-centered radical-derived spin adducts in Cu2+-containing 50 mM Tris-HCl buffered solutions (pH 7.1) of D-glucosamine, D-mannosamine, and D-galactosamine, which were previously shown to have the ability to break the single-strand of plasmid pBR322 DNA in a nucleotide sequence-specific manner. HCl-free D-glucosamine has higher DNA breaking activity, and this activity is promoted more by the presence of Cu2+ than the original D-glucosamine hydrochloride, exhibits stronger radical signals in the ESR spectrum. It is suggested that D-glucosamine is unstable around neutral pH, being converted into certain intermediate(s) such as a dihydropyrazine compound, which generate(s) carbon-centered radicals, and that, besides the hydroxyl radical, the intermediate(s) is/are responsible for DNA strand breakage.

Benzenesulfonates↗

PubMed1993

Effects of cholesterol on the miscibility of synthetic glucosamine diesters in lipid bilayers and the entrapment of superoxide dismutase into the positively charged liposomes.

Methyl-D-glucosamine-3,6-dilauroyl, dimyristoyl, dipalmitoyl or distearoyl esters were synthesized as positively charged lipids. They were incorporated into phosphatidylcholine liposomal membranes and the entrapment of superoxide dismutase (SOD) into the liposomes was attempted. The efficiency of the SOD-entrapment into the positively charged multilamellar vesicles (MLVs), comprising egg yolk phosphatidylcholine and synthetic glucosamine diesters, was enhanced by the addition of cholesterol to the membranes. A differential scanning calorimetric study showed that the miscibility (solubility) of glucosamine diesters in phosphatidylcholine-bilayers increased on the addition of cholesterol to the membranes. Cholesterol assisted in the mixing of phosphatidylcholines with positively charged glucosamine diesters and increased the positive charges on the liposomal membranes. This was confirmed by incremental increases in the zeta-potential of liposomal membranes with an increase in the cholesterol content. Entrapment of SOD thus became more efficient due to the enhanced electrostatic attraction between the positively charged membranes and the negatively charged SOD, and/or the electrostatic repulsive interactions between positively charged membranes; the latter interactions induced a thickening of the water layer in MLVs.

Cholesterol↗

PubMed2006

Diacerhein versus glucosamine in a rat model of osteoarthritis.

PURPOSE: The purpose of this study was to compare the chondroprotective effect of diacerein and glucosamine regarding degenerative changes and articular stiffness in an experimental model of arthritis. METHODS: Twenty rats underwent medial meniscectomy on the right knee. Ten animals were given diacerhein, and 10 were given glucosamine, from day 1 to the third month postoperatively, when all of them were killed. Histological and functional analysis of the knees were performed (measurement of maximum extension). RESULTS: All operated knees showed more limited extension values and more degenerative changes as compared to nonoperated contralateral sides. A comparison of the two drugs showed that the degree of articular stiffness was significantly lower with diacerein, although degenerative changes were similar. CONCLUSIONS: 1) Prophylactic use of diacerein leads to lower degree of articular stiffness when compared to glucosamine; 2) The prophylactic chondroprotective effects of diacerein and glucosamine are histologically similar.

Animals↗

PubMed1980

Effect of glucosamine on phenotype mixing of vesicular stomatitis virus with avian sarcoma virus.

The effect of glucosamine on phenotypic mixing between vesicular stomatitis virus (VSV) and avian sarcoma virus (ASV) was studied. Phenotypic mixing decreased with increase in glucosamine concentration, and, in the presence of 20 mM glucosamine, was no longer detectable. In the presence of 20 mM glucosamine, cells still produced 10(2)--10(3) focus forming units (FFU) of ASV and 10(6) plaque forming units (PFU) of VSV per milliliter. These results suggest that cells producing a relatively large amount of ASV (more than 10(3) FFU/ml) are essential for phenotypic mixing of VSV with ASV.

Animals↗

PubMed2002

Serum concentrations of keratan sulfate, osteocalcin, and pyridinoline crosslinks after oral administration of glucosamine to standardbred horses during race training.

OBJECTIVE: To determine the effects of orally administered glucosamine on concentrations of markers of bone and cartilage metabolism in Standardbred horses during race training. ANIMALS: Twenty 16- to 20-month-old Standardbreds beginning race training. PROCEDURE: Horses were randomly assigned to 2 groups. One group received glucosamine hydrochloride (4 g, PO, q 12 h), and the second (control) group received glucose (4 g, PO, q 12 h). Serum samples were obtained prior to onset of the study (baseline) and at regular intervals for 48 weeks for determination of concentrations of keratan sulfate (KS), osteocalcin (OC), and pyridinoline crosslinks (PYD). RESULTS: Osteocalcin concentrations changed significantly with time; mean serum concentrations were significantly higher than baseline values for samples obtained at 24 to 48 weeks after onset of the study. Although a significant effect of time was observed for mean concentration of KS, concentrations did not differ significantly from baseline values at any time during the study when groups were analyzed separately. However, pooled analysis revealed significant increases of mean serum KS concentration at weeks 24 and 30. Significant changes in serum PYD concentrations were not detected. Oral administration of glucosamine did not significantly affect serum concentrations of any of the markers. CONCLUSIONS AND CLINICAL RELEVANCE: Increased serum OC in clinically normal Standardbreds during race training may reflect bone formation that accompanies adaptive remodeling of the appendicular skeleton. For these experimental conditions, glucosamine did not appear to exert a detectable influence on serum concentrations of these 3 markers of connective tissue metabolism.

Administration, Oral↗

PubMed2005

Effects of glucosamine and chondroitin sulfate on mediators of osteoarthritis in cultured equine chondrocytes stimulated by use of recombinant equine interleukin-1beta.

OBJECTIVE: To determine whether glucosamine and chondroitin sulfate (CS) at concentrations approximating those achieved in plasma by oral administration would influence gene expression of selected mediators of osteoarthritis in cytokine-stimulated equine articular chondrocytes. SAMPLE POPULATION: Samples of grossly normal articular cartilage obtained from the metacarpophalangeal joint of 13 horses. PROCEDURE: Equine chondrocytes in pellet culture were stimulated with a subsaturating dose of recombinant equine interleukin (reIL)-1beta. Effects of prior incubation with glucosamine (2.5 to 10.0 microg/mL) and CS (5.0 to 50.0 microg/mL) on gene expression of matrix metalloproteinase (MMP)-1, -2, -3, -9, and -13; aggrecanase 1 and 2; inducible nitric oxide synthase (iNOS); cyclooxygenase (COX)-2; nuclear factor kappaB; and c-Jun-N-terminal kinase (JNK) were assessed by use of a quantitative real-time polymerase chain reaction assay. RESULTS: Glucosamine at a concentration of 10 microg/mL significantly reduced reIL-1beta-induced mRNA expression of MMP-13, aggrecanase 1, and JNK. Reductions in cytokine-induced expression were also observed for iNOS and COX-2. Chondroitin sulfate had no effect on gene expression at the concentrations tested. CONCLUSIONS AND CLINICAL RELEVANCE: Concentrations of glucosamine similar to those achieved in plasma after oral administration in horses exerted pretranslational regulation of some mediators of osteoarthritis, an effect that may contribute to the cartilage-sparing properties of this aminomonosaccharide. Analysis of results of this study indicated that the influence of CS on pretranslational regulation of these selected genes is limited or lacking.

ADAM Proteins↗

PubMed2004

Comparative bioavailability of a novel timed release and powder-filled glucosamine sulfate formulation--a multi-dose, randomized, crossover study.

OBJECTIVE: The absorption of 2 different formulations of glucosamine sulfate were studied in a randomized, multi-dose, two-way, crossover study. MATERIALS AND METHOD: In this study, a novel timed release pellet-filled hard gelatin shell capsule (TimeOsamine) was compared with a powder-filled hard gelatin shell capsule. The timed release capsule was used in a double dose with an interval of 12 h whereas the powder-filled hard gelatin capsule was used in a triple dose schedule with an interval of 8 h after 10 h pre-dose fasting. Twelve healthy male subjects were administered a 1,000 mg (2 x 500 mg) dose of timed release glucosamine sulfate (TimeOsamine) or a 1,500 mg (3 x 500 mg) dose of the powder-filled glucosamine sulfate formulation. The concentration of glucosamine was measured over the next 24 h. Pharmacokinetics properties including area under the curve (AUC), maximum concentration in plasma (C(max)), time to maximum plasma concentration (t(max)) were measured. RESULTS: The C(max) of the powder-filled and timed release formulation (TimeOsamine) was 543.12 ng/ml and 520.98 ng/ml, respectively. The t(max) of TimeOsamine was delayed by 4.13 h, whereas the powder-filled preparation was 1.00 h. The AUC0-24 of the 2 doses of TimeOsamine (2 x 500 mg = 1,000 mg) and the 3 doses of the powder-filled formulation (3 x 500 mg = 1,500 mg) was 6,263.32 ng x h/ml and 6,499.55 ng x h/ml, respectively. CONCLUSION: After reduction in the dose by 33%, the AUC0-24 of TimeOsamine is 96.37% with respect to the powder-filled formulation AUC0-24, which is comparable.

Adult↗

PubMed1998

Ammonium ion and glucosamine dependent increases of oligosaccharide complexity in recombinant glycoproteins secreted from cultivated BHK-21 cells.

The effect of different ammonium concentrations and glucosamine on baby hamster kidney (BHK)-21 cell cultures grown in continuously perfused double membrane bioreactors was investigated with respect to the final carbohydrate structures of a secretory recombinant glycoprotein. The human interleukin-2 (IL-2) mutant glycoprotein variant IL-Mu6, which bears a novel N-glycosylation site (created by a single amino acid exchange of Gln100 to Asn), was produced under different defined protein-free culture conditions in the presence or absence of either glutamine, NH4Cl, or glucosamine. Recombinant glycoprotein products were purified and characterized by amino acid sequencing and carbohydrate structural analysis using matrix-assisted laser desorption ionization time of flight mass spectrometry, high-pH anion-exchange chromatography with pulsed amperometric detection, and methylation analysis. In the absence of glutamine, cells secreted glycoprotein forms with preponderantly biantennary, proximal fucosylated carbohydrate chains (85%) with a higher NeuAc content (58%). Under standard conditions in the presence of 7.5 mM glutamine, complex-type N-glycans were found to be mainly biantennary (68%) and triantennary structures (33%) with about 50% containing proximal alpha1-6-linked fucose; 37% of the antenna were found to be substituted with terminal alpha2-3-linked N-acetylneuraminic acid. In the presence of 15 mM exogenously added NH4Cl, a significant and reproducible increase in tri- and tetraantennary oligosaccharides (45% of total) was detected in the secretion product. In glutamin-free cultures supplemented with glucosamine, an intermediate amount of high antennary glycans was detected. The increase in complexity of N-linked oligosaccharides is considered to be brought about by the increased levels of intracellular uridine diphosphate-GlcNAc/GalNAc. These nucleotide sugar pools were found to be significantly elevated in the presence of high NH3/NH4+ and glucosamine concentrations.

Acetylgalactosamine↗

PubMedDate not supplied

Single dose pharmacokinetics and bioavailability of glucosamine in the rat.

PURPOSE: To study pharmacokinetics of glucosamine following various routes of administration of the hydrochloride salt to rats and locate the site of its first-pass metabolism. METHODS: Rat were cannulated in the jugular vein and single intravenous, oral and intra peritoneal doses of 350 mg/kg were administered. Serial blood samples were collected and plasma glucosamine concentrations were determined using HPLC. RESULTS: After intravenous administration, the apparent terminal half-life (1.09 +/- 0.98 h), apparent steady state volume of distribution (2.1 +/- 1.1 L.kg(-1)) and total body clearance (2.61 +/- 0.81 L.kg(-1.h-1)) were calculated. The peak plasma concentration, after oral administration, occurred approximately 30 min post-dose and the absolute bioavailability was 0.19. Glucosamine was completely bioavailable after intraperitoneal administration. CONCLUSION: Orally administered glucosamine is rapidly absorbed, highly distributed and efficiently cleared. The gut rather than liver is mainly responsible for the first pass metabolism since reduced bioavailability is observed after oral but not intraperitoneal doses.

Administration, Oral↗

PubMedDate not supplied

Capillary electrophoresis separation of autocondensation glycation products of glucosamine.

Glucosamine nonenzymatically forms autocondensation glycation products under physiological conditions. Many studies have reported the effectiveness of oral doses of glucosamine alone or in combination with the galactosamine containing chondroitin in treating osteoarthritis. However, none of these studies has considered whether it is the glucosamine itself and/or one or more of its autocondensation products that exert this effect. A capillary electrophoresis method was developed to monitor the nonenzymatic formation of autocondensation glycation products of glucosamine, galactosamine, and mannosamine under physiological conditions. Major components were detected and separated by CE with a UV detector. The effects of concentration and incubation time on product species were determined. The method described is simple, rapid, and effective.

Electrophoresis, Capillary↗

PubMed2003

[Glucosamine concentration in serum of old persons with hyperinsulinemia and normal insulin levels].

Increased glucose metabolism through the hexosamine biosynthesis pathway has been shown to mediate many of adverse effects i.e. desensitisation of glucose transport in tissues, an inhibition of glycolysis and glycogen synthesis in skeletal muscles, an impairment of insulin secretion in pancreatic islet cells, arteriosclerosis and nephropathy by stimulation of growth factor TGF-alpha and TGF-beta 1 promoters expression. The aim of the presented study was to compare of glucosamine concentrations in the blood serum between elderly human subjects (women and men) with hyperinsulinaemia and normoinsulinaemia. Subjects were divided into two groups: a group of 16 subjects with hyperinsulinaemia (concentration of fasting insulin is higher than 15 mU/l) and a group of 19 subjects with normoinsulinaemia (concentration of insulin was less or equal 15 mU/l). In the venous blood serum concentrations of insulin, C-peptide, glucose and glucosamine were determined. The Caltrac accelerometer was used to estimate energy expenditure in subgroup of 20 subjects: 10 subjects with hyperinsulinaemia and 10 with normoinsulinaemia. Significant differences were found between glucosamine and insulin concentrations (p < 0.01) and between C-peptide concentrations (p < 0.05) in both groups investigated. The mean value of the glucosamine concentration in the group with hyperinsulinaemia was higher by 22.6 mg/dl in comparison to mean value established in the group with normoinsulinaemia. Mean values of total and related to physical activity energy expenditure per day per 1 kg of body mass in the group with hyperinsulinaemia were less (p < 0.05) compared to the group with normoinsulinaemia. The presented results show that hyperinsulinaemia may contribute to the hyperactivity of hexosamine biosynthesis pathway.

Aged↗

PubMedDate not supplied

Osteoarthritic patients with high cartilage turnover show increased responsiveness to the cartilage protecting effects of glucosamine sulphate.

OBJECTIVE: Glucosamine sulphate has been shown in a large double-blind, placebo-controlled clinical trial to prevent structural damage and improve clinical symptoms of osteoarthritis (OA). We investigated whether early response in a newly developed biochemical marker of collagen type II degradation (CTX-II, CartiLaps ELISA) could reflect the long-term preservation of hyaline cartilage. METHODS: Study subjects comprised 212 knee OA patients participating in a clinical trial of the effects of glucosamine sulphate. Disease symptoms were assessed quarterly by WOMAC scoring and X-ray analysis was performed at baseline and after 3 years. Urine samples were obtained at baseline and after 1, 2 and 3 years for measurement in the CartiLaps assay. The measurements were corrected for creatinine. RESULTS: At baseline the patients had an average concentration of urinary CTX-II of 222.4 +/- 159.5 ng/mmol creatinine. This was significantly above the CTX-II levels measured in urine samples from 415 healthy controls (169.1 +/- 92.3 ng/mmol, p < 0.0001). There was no significant difference in the CTX-II response in the placebo group and the glucosamine treated group. However, those with high cartilage turnover presented a significant decrease in CTX-II after 12-month glucosamine treatment. Thus, three group with CTX II concentrations above normal average + 1SD decreased 15.5% after 12-month therapy. The 12 months change in CTX-II in OA patients with elevated CTX-II at baseline correlated with the change in average joint space width observed after 36 months (R = 0.43, p < 0.05). Increased baseline levels of CTX-II were associated with a worsening of the WOMAC index (p < 0.01). CONCLUSION: The data indicate that measurement of urinary collagen type II C-telopeptide fragments enables the identification of OA patients with high cartilage turnover who at the same time are most responsive to therapy with structure modifying drugs.

Aged↗