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N-terminal His(7)-modification of glucagon-like peptide-1(7-36) amide generates dipeptidyl peptidase IV-stable analogues with potent antihyperglycaemic activity

Biomedical Sciences Research Institute Computer Science Research Institute Environmental Sciences Research Institute Nanotechnology & Advanced Materials Research Institute

Green, BD, Mooney, MH, Gault, Victor, Irwin, Nigel, Bailey, CJ, Harriott, P, Greer, B, O'Harte, Finbarr and Flatt, Peter (2004) N-terminal His(7)-modification of glucagon-like peptide-1(7-36) amide generates dipeptidyl peptidase IV-stable analogues with potent antihyperglycaemic activity. JOURNAL OF ENDOCRINOLOGY, 180 (3). pp. 379-388. [Journal article]

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Abstract

Glucagon-like peptide-1(7-36)amide (GLP-1) possesses several unique and beneficial effects for the potential treatment of type 2 diabetes. However, the rapid in-activation of GLP-1 by dipeptidyl peptidase IV (DPP IV) results in a short half-life in vivo (less than 2 min) hindering therapeutic development. In the present study, a novel His(7)-modified analogue of GLP-1, N-pyroglutamyl-GLP-1, as well as N-acetyl-GLP-1 were synthesised and tested for DPP IV stability and biological activity. Incubation of GLP-1 with either DPP IV or human plasma resulted in rapid degradation of native GLP-1 to GLP-1 (9-36),amide, while N-acetyl-GLP-1 and N-pyroglutamyl-GLP-1 were completely resistant to degradation. N-acetyl-GLP-1 and N-pyroglutamyl-GLP-1 bound to the GLP-1 receptor but had reduced affinities (IC50 values 32.9 and 6.7 nM, respectively) compared with native GLP-1 (IC50 0.37 nM). Similarly, both analogues stimulated cAMP production with EC50 values of 16.3 and 27 nM respectively compared with GLP-1 (EC50 4.7 nM). However, N-acetyl-GLP-1 and N-pyroglutamyl-GLP-1 exhibited potent insulinotropic activity in vitro at 5.6 mM glucose (P<0.05 to P<0.001) similar to native GLP-1. Both analogues (25 nM/kg body weight) lowered plasma glucose and increased plasma insulin levels when administered in conjunction with glucose (18 nM/kg body weight) to adult obese diabetic (ob/ob) mice. N-pyroglutamyl-GLP-1 was substantially better at lowering plasma glucose compared with the native peptide, while N-acetyl-GLP-1 was significantly more potent at stimulating insulin secretion. These studies indicate that N-terminal modification of GLP-1 results in DPP IV-resistant and biologically potent forms of GLP-1. The particularly powerful antihyperglycaemic action of N-pyroglutamyl-GLP-1 shows potential for the treatment of type 2 diabetes.

Item Type:Journal article
Faculties and Schools:Faculty of Life and Health Sciences
Faculty of Life and Health Sciences > School of Biomedical Sciences
Faculty of Life and Health Sciences > School of Pharmacy and Pharmaceutical Science
Research Institutes and Groups:Biomedical Sciences Research Institute
Biomedical Sciences Research Institute > Diabetes
ID Code:3025
Deposited By:Professor Peter Flatt
Deposited On:14 Jan 2010 15:40
Last Modified:19 Nov 2012 16:26

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