PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “GLUCOSAMINE”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 631 records · Page 35Linked to original sources
PubMed1977

Extracellular matrix synthesis in blastula and gastrula stages of normal and hybrid frog embryos. III. Characterization of galactose- and glucosamine-labelled materials.

Normal Rana pipiens gastrulae show more incorporation of isotopically-labelled galactose and glucosamine into TCA-insoluble materials than blastulae. Interspecific hybrid embryos which undergo developmental arrest at the onset of gastrulation often synthesize reduced amounts of galactose- and glucosamine-labelled materials. These materials are high-molecular weight, but not collagen. After pronase digestion, labelled materials elute in the void volume of Sephadex G-50. Labelled materials migrate slowly on cellulose acetate, bind to several kinds of anion exchangers and elute at low ionic strength, are precipitated by cetyl pyridinium chloride (CPC) when mixed with carrier compounds, and are not degraded by Clostridium neuraminidase or Streptomyces, leech, and bovine testicular hyaluronidases.

Animals↗
PubMed2004

Hexosamines are unlikely to function as a nutrient-sensor in 3T3-L1 adipocytes: a comparison of UDP-hexosamine levels after increased glucose flux and glucosamine treatment.

Whether the hexosamine biosynthesis pathway acts as a nutrient-sensing pathway is still unclear. Glucose is directed into this pathway by GFAT. Because the activity of GFAT is tightly regulated, we examined whether UDP-hexosamine levels can increase significantly and dose-dependently in response to elevated glucose concentrations. In glucosamine-treated 3T3-L1 adipocytes, inhibition of insulin-stimulated glucose uptake was highly correlated with UDP-hexosamine levels (r = -0.992; p < 0.0001 for UDP-GlcNAc and r = -0.996; p < 0.0001 for UDP-GalNAc). Incubation of 3T3-L1 adipocytes with 0.1 microM insulin for 24 h in medium containing 1 and 5 mM glucose increased the rate of glucose uptake by 365% and 175% compared to untreated cells, respectively. This increase was not observed when the cells were incubated for 24 h with insulin in medium containing 10 or 25 mM glucose. However, treatment of cells with insulin and 1, 5, 10, or 25 mM glucose resulted in similar increases in levels of UDP-GlcNAc and UDP-GalNAc that always amounted to approx 30-40% above baseline values. This led us to conclude that despite exposure of adipocytes to conditions of extreme and prolonged glucose disposal, the increases in cellular UDP-hexosamines were minimal and not dependent on the extracellular glucose concentration. Taken together, our results are in line with the hypothesis that in glucosamine-treated adipocytes UDP-hexosamines influence insulin-stimulated glucose uptake. However, our observations in glucose-treated adipocytes argue against the possibility that UDP-hexosamines function as a nutrient-sensor, and question the role of the hexosamine biosynthesis pathway in the pathogenesis of insulin resistance.

3T3-L1 Cells↗
PubMed2002

Folliculogenesis and ovarian expression of mRNA encoding aromatase in anoestrous sheep after 5 days of glucose or glucosamine infusion or supplementary lupin feeding.

Improved nutrition increases ovulation rate in sheep and there is evidence that intra-ovarian pathways mediate responses to nutrition. An experiment was conducted to examine the effect of dietary energy on folliculogenesis. Anoestrous Merino ewes were fed a diet of wheat straw alone (control, n = 5), or wheat straw supplemented with lupins (500 g day(-1), n = 5). Other ewes were fed wheat straw and infused with glucose (50 mmol h(-1), n = 5) or with glucosamine (3.5 mmol h(-1), n = 5). Intravaginal progestagen sponges were inserted for 12 days, and nutritional treatments were started 5 days before sponge removal. At sponge removal, the ewes were injected with a regimen of GnRH pulses (500 ng every 4 h from 0 to 12 h; 250 ng every 2 h from 14 to 24 h; and 200 ng every 1 h from 25 to 36 h) to simulate normal follicular development. Thirty-six hours after sponge removal, the animals were killed and the ovaries were collected and stored at -80 degrees C. The ovaries were sectioned serially every 10 microm. Every 20th section was stained (to estimate number and diameter of follicles) and every 17-19th section was probed by in situ hybridization for P(450) aromatase. Data were analysed using ANOVA and chi-squared tests. There was an effect of treatment (P < 0.05) on the number of follicles 2-3, 3-4 and 6-7 mm in diameter. Aromatase-positive follicles (1.6-7.9 mm) were detected in 31 follicles from 15 ewes across all four groups. In ten animals, the largest follicle was aromatase-positive. The diameters of aromatase-positive follicles were larger (P = 0.004) in lupin fed compared with glucose-infused ewes (4.9 +/- 0.5, 3.6 +/- 0.7, 5.3 +/- 0.5 and 4.2 +/- 0.5 mm for control, glucose-infused, lupin-fed and glucosamine-infused groups, respectively). Treatment did not affect the plasma concentration of FSH when compared with controls, indicating that the energy supplements were modifying recruited (2-3 mm and 3-4 mm) and selected follicles (> 6 mm) directly. In conclusion, dietary energy can directly stimulate folliculogenesis in recruited and selected follicles, and this effect may be mediated by changes in systemic leptin concentrations and the hexosamine energy-sensing pathway in the follicle.

Analysis of Variance↗
PubMed1994

Comparative metabolism of 3H-glucosamine by fibroblast populations exposed to cyclosporine.

Cyclosporine and nifedipine therapy produces gingival overgrowth in many patients. Neither the mechanism underlying this undesirable side effect nor the possibility of synergism between these drugs is known, although many renal transplant patients receive both drugs. This study compared the rates of 3H-glucosamine utilization by three groups of fibroblasts: untreated gingival fibroblasts, fibroblasts from gingival overgrowth tissue of a patient receiving both cyclosporine and nifedipine, and normal gingival fibroblasts exposed to cyclosporine-A in vitro. Significant differences in the rates of deposition of 3H-glucosamine into the extracellular matrix by each group of gingival fibroblasts were demonstrated, suggesting that increased rates of deposition of proteoglycans into the gingival extracellular matrix by fibroblasts should be further investigated as a biologic mechanism for gingival overgrowth.

Adult↗
PubMed2005

Effect of glucosamine and chondroitin sulfate on regulation of gene expression of proteolytic enzymes and their inhibitors in interleukin-1-challenged bovine articular cartilage explants.

OBJECTIVE: To determine the effects of glucosamine (GLN) and chondroitin sulfate (CS), at concentrations attainable in vivo, on expression of genes encoding proteolytic enzymes, enzyme inhibitors, and macromolecules of articular cartilage in interleukin-1(IL-1)-challenged bovine cartilage explants. SAMPLE POPULATION: Articular cartilage explants harvested from 9 steers. PROCEDURES: Cartilage explants were exposed to media containing 10% fetal bovine serum (FBS) only, IL-1 (50 ng/mL), IL-1 with GLN (5 microg/mL), IL-1 with CS (20 microg/mL), or IL-1 with GLN and CS for 24 and 48 hours. Cartilage was frozen, and RNA was extracted. Gene expression of matrix metalloproteinases (MMPs)-2, -3, -9, -13, and -14; aggrecanases (Aggs)-1 and -2; tissue inhibitors of metalloproteinases (TIMPs)-1, -2, and -3; and type II collagen and aggrecan were assessed with quantitative real-time polymerase chain reaction. RESULTS: Upregulated MMP-3, MMP-13, and Agg-1 transcripts at 24 hours were repressed by the GLN and CS combination by at least approximately 6-fold. Glucosamine was effective in suppressing IL-1-induced mRNA expression of MMP-13, Agg-1, and Agg-2, whereas CS was effective in decreasing IL-1-induced MMP-13 transcript at 24 hours. At 48 hours, GLN and CS added separately and in combination significantly abrogated Agg-1 and Agg-2 gene induction. The combination also decreased IL-1-stimulated MMP-13 transcript. CONCLUSIONS AND CLINICAL RELEVANCE: GLN and CS, at concentrations that are within the range measured in synovial fluid and blood after oral administration, may regulate expression of matrix degrading enzymes and their inhibitors at the transcriptional level, providing a plausible mechanism for their purported chondroprotective properties.

Aggrecans↗
PubMed2005

The efficacy of glucosamine and chondroitin sulfate in the treatment of osteoarthritis: are these saccharides drugs or nutraceuticals?

This review summarizes recent knowledge on the efficacy of glucosamine (GS) and/or chondroitin sulfate (CS) in the therapy of mild to moderate osteoarthritis (OA). OA, the most common joint disease is a significant source of disability, quality of life impairment and a considerable burden to any health care system. In the Czech Republic, glucosamine sulfate (GS) and chondroitin sulfate (CS) are available both as prescription drugs and as food supplements. Based on available data both are useful in the earlier stages of OA when combined with other modalities such as weight loss and exercises. They appear to relieve pain and improve range of the joint motion. In addition, they also display mild anti-inflammatory effects. However, controversy still exists over their ability to change significantly the natural history of the osteoarthritic joint. This effect is not easy to demonstrate for any other treatment modalities apart from joint replacement. Monitoring the cure efficacy by X-ray has been recently criticised and hence future techniques are anticipated for this reason. Further, long-term oral administration is required to obtain slightly increased levels of GS and/or CS in human blood. Both reviewed saccharides are well tolerated with negligible adverse reactions. In conclusion, the authors suggest that GS and CS should be classified as food supplements only.

Chondroitin Sulfates↗
PubMed1984

Anticapsin, an active-site directed irreversible inhibitor of glucosamine-6-phosphate synthetase from Escherichia coli.

Glucosamine-6-phosphate synthetase from Escherichia coli K-12 is progressively inactivated L-beta-(2,3-epoxycyclohexyl-4-on)alanine (anticapsin). With increasing concentrations of anticapsin the reaction exhibits rate saturation: the minimum inactivation half-time is 1.15 minutes, with a Kin alpha ct of 2.5 microM. Glutamine and competitive inhibitors protect against inactivation. Fructose-6-phosphate promotes the inactivation rate. It is concluded that anticapsin is an active-site directed glutamine analog in the reaction catalyzed by glucosamine-6-phosphate synthetase.

Alanine↗
PubMed1999

Glucosamine sulfate.

Glucosamine sulfate's role in halting or reversing joint degeneration appears to be directly due to its ability to act as an essential substrate for, and to stimulate the biosynthesis of, the glycosaminoglycans and the hyaluronic acid backbone needed for the formation of the proteoglycans found in the structural matrix of joints. Successful treatment of osteoarthritis must effectively control pain and should slow down or reverse the progression of the degeneration. Biochemical and pharmacological data combined with animal and human studies demonstrate that glucosamine sulfate is capable of satisfying both of these criteria.

Glucosamine↗
PubMedDate not supplied

[Effect of glucosamine on amino acid transport and intensity of protein synthesis in liver cells in an inflammation model].

The effect of glucosamine on the transport of amino acids and protein synthesis in hepatocytes when modelling inflammation was studied. It was found the considerable decrease of the amino acid transport via hepatocyte membranes. The protein synthesis intensity was displayed as also significantly reduced. Administration of glucosamine to the rats normalized both studied processes.

Amino Acids↗
PubMed2001

Oral polymeric N-acetyl-D-glucosamine and osteoarthritis.

Many patients with arthritis are using alternative modes of therapy, including nutritional supplements, to treat their arthritis. Most patients never tell their doctors that they are taking alternative medications, and few doctors even ask about such activities. Over-the-counter supplements are expensive and consume large amounts of patients' healthcare dollars. Glucosamine has been widely touted as being an effective arthritis treatment. The authors designed and undertook a study to test the efficacy of a polymer of N-acetyl-D-glucosamine (NAG), or POLY-Nag, in a double-blind, placebo-controlled study in patients with osteoarthritis. Results indicate that POLY-Nag may be useful in treating patients with osteoarthritis.

Acetylglucosamine↗
PubMed1975

Effect of D-glucosamine and D-galactosamine on the uridine nucleotide concentration in mouse myeloid tumor (Graffi) and myeloma MOPC-21.

The effect of D-glucosamine and D-galactosamine on the content of uridine nucleotides in myeloid tumor (Graffi) and myeloma MOPC-21 of mice was investigated in vivo. After treatment with aminosugars a marked decrease in UTP and UDP-glucose quantity was found. The trapping of uridine phosphates by formation of UDP-sugar derivatives was different in the two tumors and depended on the aminosugar employed. D-glucosamine provoked an increase in the UDP-N-acetylglucosamine pool size in myeloid tumor (Graffi) and myeloma MOPC-21. D-galactosamine administration led to formation of UDP-galactosamine and UDP-N-acetylglucosamine in myeloma MOPC-21, while in myeloid tumor (Graffi) an increase in the content of UDP-N-acetylglucosamine was obtained only.

Animals↗
PubMed2002

Glucosamine. A nutraceutical in osteoarthritis.

BACKGROUND: Glucosamine is an amine-sugar that has been marketed as a natural product for the treatment of osteoarthritis. It has been popularized in the complementary section of pharmacies as a safe over-the-counter treatment for osteoarthritic pain. OBJECTIVE: We review the literature on the efficacy and safety of glucosamine in osteoarthritis. DISCUSSION: Recent research suggests that it may not only provide symptomatic pain relief, but may have a role in chondroprotection.

Glucosamine↗
PubMed2002

[Glucosamine and chondroitin sulfate as a possible treatment for osteoarthritis].

The nutritional supplements glucosamine and chondroitine sulphate are widely used in the treatment of osteoarthritis. In published studies, glucosamine used in a dosage of 1.5 gram daily is, after a period of 2 to 4 weeks, just as effective as low doses of NSAIDs in alleviating pain. Chondroitine sulphate has been less well investigated. There are indications that it affects the symptoms of osteoarthritis, even though this effect only occurs after a longer period of time. The side effects for both substances are minor. A disease-modifying effect (defined as delay of radiological progression of osteoarthritis) has not been proven.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2002

Active ingredient consistency of commercially available glucosamine sulfate products.

OBJECTIVE: To assess the content of active ingredient in over-the-counter (OTC) glucosamine sulfate (GLS) preparations. METHODS: We analyzed in a coded, blind manner 14 commercially available capsules or tablets of GLS, plus one herbal mixture as a control. We used a high performance liquid chromatography system as described. RESULTS: The amount of free base varied from 41 to 108% of the mg content stated on the label; the amount of glucosamine varied from 59 to 138% even when expressed as sulfate. CONCLUSION: If GLS is used as a therapeutic agent, it is important that the products conform to a standard in their description. The content is probably best expressed in terms of free base.

Commerce↗
PubMedDate not supplied

[Experimental study of the effect of glucosamine hydrochloride on metabolic and repair processes in connective tissue structures].

The effects of glucosamine hydrochloride on the metabolic and repair processes were studied on a model of post-traumatic osteoarthrosis in the articular cartilage and on a model of post-traumatic keratitis in the cornea. The administration of glucosamine hydrochloride stimulated repair and favored inhibition of dystrophic post-traumatic processes in the connective-tissue structures. It is suggested that a probable mechanism of the drug action consists in stimulation of the synthesis of glucosaminoglycanes and collagen.

Animals↗
PubMed2003

[Glucosamine and chondroitin sulfate in the treatment of arthritis].

Glucosamine and chondroitin sulphate are naturally occurring substances used by an increasing number of Danish patients with arthritis, although neither of the compounds has been approved for sale in Denmark. Both substances can be taken by mouth and have no known significant side effects. Glucosamine and chondroitin sulphate have been examined in laboratory and animal experiments, and in several clinical studies, which have shown some effect on the symptoms of early or moderate arthritis. The long-term effect has not been evaluated sufficiently and studies of the relation between dose and effect are lacking for both compounds.

Administration, Oral↗
PubMed2006

[Glucosamine as a pain-modifying drug in osteorthritis. What's new in 2006].

Glucosamine is widely used as a symptom-modifying drug in osteoarthritis. New clinical trials, from Europe and the United-States bring some clarification regarding the optimal formulation and doses to be used in knee osteoarthritis. Their results are supported by new pharmacokinetic and preclinical studies, explaining the mode of action of glucosamine in osteoarthritis.

Arthralgia↗