Glucagon-like peptide-1 (GLP-1) receptor

The use of glucagon-like peptide-1 (GLP-1) as a routine treatment for type 2 diabetes mellitus is undermined by its short biological half-life. A cause of degradation is its cleavage at the N-terminal HAE sequence by the enzyme dipeptidyl peptidase IV (DPP IV). To protect from DPP IV, we have studied the biological activity of a GLP-1 analog in which 6-aminohexanoic acid (Aha) is inserted between histidine and alanine at positions 7 and 8. We have compared the biological activity of this new compound, GLP-1 Aha(8), with the previously described GLP-1 8-glycine (GLP-1 Gly(8)) analog. GLP-1 Aha(8) (10 nM) was equipotent with GLP-1 (10 nM) in stimulating insulin secretion in RIN 1046-38 cells. As with GLP-1 Gly(8), the binding affinity of GLP-1 Aha(8) for the GLP-1 receptor in intact Chinese hamster ovary (CHO) cells expressing the human GLP-1 receptor (CHO/GLP-1R cells) was reduced (IC(50): GLP-1, 3.7 +/- 0.2 nM; GLP-1 Gly(8), 41 +/- 9 nM; GLP-1 Aha(8), 22 +/- 7 nM). GLP-1 Aha(8) was also shown to stimulate intracellular cAMP production 4-fold above basal at concentrations as low as 0.5 nM. However, it exhibited a higher ED(50) when compared to GLP-1 and GLP-1 Gly(8) (ED(50): GLP-1, 0.036 +/- 0.002 nM, GLP-1 Gly(8), 0.13 +/- 0.02 nM, GLP-1 Aha(8), 0.58 +/- 0.03 nM). A series of D-amino acid-substituted GLP-1 compounds were also examined to assess the importance of putative peptidase-sensitive cleavage sites present in the GLP-1 molecule. They had poor binding affinity for the GLP-1 receptor, and none of these compounds stimulated the production of intracellular cAMP in CHO/GLP-1R cells or insulin secretion in RIN 1046-38 cells[4].

Significant dose-dependent reductions in 24-h mean weighted glucose [area under the curve((0-24 h))] were observed, with placebo-adjusted least squares means difference values in the 32-mg cohort of -34.8 and -56.4 mg/dl [95% confidence interval (-54.1, -15.5) and (-82.2, -30.5)] for d 2 and 9, respectively. Placebo-adjusted fasting plasma glucose decreased by -26.7 and -50.7 mg/dl [95% confidence interval (-46.3, -7.06) and (-75.4, -26.0)] on d 2 and 9, respectively. Postprandial glucose was also reduced. No hypoglycemic episodes were detected in the albiglutide cohorts. The frequency and severity of the most common adverse events, headache and nausea, were comparable with placebo controls. Albiglutide half-life ranged between 6 and 7 d. The pharmacokinetics or pharmacodynamic of albiglutide was unaffected by injection site. Conclusions: Albiglutide improved fasting plasma glucose and postprandial glucose with a favorable safety profile in subjects with type 2 diabetes. Albiglutide's long half-life may allow for once-weekly or less frequent dosing[1].

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GLP-1 Aha(8) (24 nmol/kg) administered sc to fasted Zucker (fa/fa) rats (mean blood glucose, 195 +/- 32 mg/dl) lowered blood glucose levels to a nadir of 109 +/- 3 mg/dl, and it remained significantly lower for 8 h. Matrix-assisted linear desorption ionization-time of flight mass spectrometry of GLP-1 Aha(8) incubated with DPP IV (37 C, 2 h) did not exhibit an N-terminal degradation product. Taken together, these results show that insertion of Aha after the 7 position in GLP-1 produces an effective, long-acting GLP-1 analog, which may be useful in the treatment of type 2 diabetes mellitus[4].

Objectives: The objectives were to investigate pharmacodynamics, pharmacokinetics, safety, and tolerability of albiglutide in type 2 diabetes subjects. Methods: In a single-blind dose-escalation study, 54 subjects were randomized to receive placebo or 9-, 16-, or 32-mg albiglutide on d 1 and 8. In a complementary study, 46 subjects were randomized to a single dose (16 or 64 mg) of albiglutide to the arm, leg, or abdomen.[1]

[1]. Pharmacodynamics, pharmacokinetics, safety, and tolerability of albiglutide, a long-acting glucagon-like peptide-1 mimetic, in patients with type 2 diabetes. J Clin Endocrinol Metab. 2008 Dec;93(12):4810-7.

[2]. Albiglutide: a review of its use in patients with type 2 diabetes mellitus. Drugs. 2015 Apr;75(6):651-63.

[3]. Albiglutide: a new GLP-1 receptor agonist for the treatment of type 2 diabetes. Ann Pharmacother. 2014 Nov;48(11):1494-501.

[4]. Insertion of an N-terminal 6-aminohexanoic acid after the 7 amino acid position of glucagon-like peptide-1 produces a long-acting hypoglycemic agent. Endocrinology. 2001 Oct;142(10):4462-8.

Albiglutide (Eperzan(®), Tanzeum(®)), administered subcutaneously once weekly, is a glucagon-like peptide (GLP)-1 receptor agonist approved for the treatment of type 2 diabetes mellitus in several countries. Albiglutide has a longer half-life than native GLP-1, since it is resistant to degradation by the dipeptidyl peptidase-4 enzyme. As an incretin mimetic, albiglutide enhances glucose-dependent insulin secretion, suppresses inappropriate glucagon secretion, delays gastric emptying and reduces food intake. Several phase III clinical trials have demonstrated the efficacy of albiglutide in terms of improving glycaemic control in patients with inadequately controlled type 2 diabetes, including its use as monotherapy or add-on therapy to other antidiabetic agents (e.g. metformin, sulfonylureas, thiazolidinediones and insulins). In addition to improving glycaemic control, albiglutide had beneficial effects on bodyweight. These improvements in glycaemic control and reductions in bodyweight were maintained during long-term treatment (up to 3 years). Albiglutide was generally well tolerated in clinical trials, with mild to moderate gastrointestinal adverse events seen most commonly. Albiglutide has a convenient once-weekly administration regimen and a low risk of hypoglycaemia (except when used in combination with agents that may be associated with hypoglycaemia, such as sulfonylureas or insulin). Thus, albiglutide is an effective and generally well tolerated treatment option for patients with inadequately controlled type 2 diabetes.[2]

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Objective: To review the pharmacology, pharmacokinetics, safety, and efficacy of albiglutide, a glucagon-like peptide-1 receptor agonist (GLP-1 RA) in type 2 diabetes (T2D). Data sources: A MEDLINE search (1950-June 2014) was conducted using the keyword albiglutide. References were reviewed to identify additional sources. Study selection and data extraction: Articles evaluating pharmacokinetics, pharmacodynamics, safety, or efficacy of albiglutide were included. Data synthesis: Albiglutide is a long-acting GLP-1 RA that lowers glycosylated hemoglobin (A1C) and reduces weight by stimulating glucose-dependent insulin secretion, suppressing glucagon secretion, delaying gastric emptying, and promoting satiety. Albiglutide has a long half-life as a result of resistance to degradation by dipeptidyl peptidase-4 and fusion to albumin, thus allowing once-weekly dosing. Albiglutide has been studied as monotherapy and add-on therapy to metformin, sulfonylureas, thiazolidinediones, insulin glargine, and varying combinations of these agents. Clinical studies have shown albiglutide to be superior to placebo, sitagliptin, and glimepiride and noninferior to insulin glargine and insulin lispro at reducing A1C in T2D patients, with A1C changes from baseline ranging from -0.55% to -0.9%. Noninferiority was not achieved when compared to liraglutide and pioglitazone. Weight changes ranged from +0.28 to -1.21 kg. The most common side effects are upper-respiratory-tract infections, diarrhea, nausea, and injection-site reactions. Conclusion: Albiglutide is the fourth GLP-1 RA approved in the United States. Advantages include once-weekly dosing and fewer gastrointestinal side effects compared with liraglutide, but it is less effective at reducing A1C and weight compared to liraglutide. It has not been compared head to head with other GLP-1 RAs. [3]

224638-84-0

Albiglutide fragment TFA;Albiglutide;782500-75-8

His-Gly-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Val-Ser-Ser-Tyr-Leu-Glu-Gly-Gln-Ala-Ala-Lys-Glu-Phe-Ile-Ala-Trp-Leu-Val-Lys-Gly-Arg-NH2

HGEGTFTSDVSSYLEGQAAKEFIAWLVKGR-NH2

Typically exists as solid at room temperature

8-Glycine-36-L-argininamide-7-36-Glucagon-like peptide 1 (Octodon degus); 224638-84-0; H-His-Gly-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Val-Ser-Ser-Tyr-Leu-Glu-Gly-Gln-Ala-Ala-Lys-Glu-Phe-Ile-Ala-Trp-Leu-Val-Lys-Gly-Arg-NH2

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Please refer to the "Guidelines for Dissolving Peptides" section in the 4th page of the "Instructions for use" file (upper-right section of this webpage) for how to dissolve peptides.

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Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)