Properties of native and in vitro glycosylated forms of the glucagon-like peptide-1 receptor antagonist exendin (9–39)
| Autor: | Åke P. Elhammer, Philip S. Burton, Janet A. Meurer, Jerry R. Colca |
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| Rok vydání: | 1999 |
| Předmět: |
Male
endocrine system medicine.medical_specialty Glycosylation medicine.drug_class Endocrinology Diabetes and Metabolism Peptide In Vitro Techniques law.invention Rats Sprague-Dawley Endocrinology Glucagon-Like Peptide 1 In vivo law Internal medicine Chlorocebus aethiops Cyclic AMP medicine Animals Humans Protein Precursors Receptor chemistry.chemical_classification Peptide analog Chemistry digestive oral and skin physiology Biological activity Glucagon Receptor antagonist Peptide Fragments In vitro Rats carbohydrates (lipids) Diabetes Mellitus Type 2 Biochemistry Recombinant DNA hormones hormone substitutes and hormone antagonists |
| Zdroj: | Metabolism. 48:716-724 |
| ISSN: | 0026-0495 |
| DOI: | 10.1016/s0026-0495(99)90170-1 |
| Popis: | The intestinal hormone glucagon-like peptide-1-(7-36)-amide (GLP-1) has recently been implicated as a possible therapeutic agent for the management of type 2 non-insulin-dependent diabetes mellitus (NIDDM). However, a major difficulty with the delivery of peptide-based agents is their short plasma half-life, mainly due to rapid serum clearance and proteolytic degradation. Using a peptide analog of GLP-1, the GLP-1 receptor antagonist exendin(9-39), we investigated whether the conjugation of a carbohydrate structure to exendin(9-39) would generate a peptide with intact biological activity and improved survival in circulation. The C-terminal portion of exendin(9-39) was reengineered to generate an efficient site for enzymatic O-glycosylation. The modified exendin(9-39) peptide (exe-M) was glycosylated by recombinant UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase 1 (GalNAc-T1) alone or in conjunction with a recombinant GalNAc alpha2,6-sialyltransferase (Sialyl-T), resulting in exe-M peptides containing either the monosaccharide GalNAc or the disaccharide NeuAc alpha2,6GalNAc. The nonglycosylated and glycosylated forms of exe-M competed with nearly equal potency (> 90% of control) with the binding of [125I]GLP-1 to human GLP-1 receptors expressed on stably transfected COS-7 cells. In addition, each peptide was equally effective for inhibiting GLP-1-induced cyclic adenosine monophosphate (cAMP) production in vitro. Studies with rats demonstrated that the modified and glycosylated forms of exendin(9-39) could antagonize exogenously administered GLP-1 in vivo. Interestingly, glycosylated exendin(9-39) homologs were more than twice as effective as the nonglycosylated peptide for inhibiting GLP-1-stimulated insulin production in vivo, suggesting a longer functional half-life in the circulation for glycosylated peptides. Results from in vivo studies with 3H-labeled peptides suggest that the glycosylated peptides may be less susceptible to modification in the circulation. |
| Databáze: | OpenAIRE |
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