Pharmacological characterization and antidiabetic activity of a long-acting glucagon-like peptide-1 analogue conjugated to an antithrombin III-binding pentasaccharide.
OBJECTIVE
To examine the biological characteristics of a novel glucagon-like peptide-1 (GLP-1) conjugate, in which an antithrombin III (ATIII)-binding pentasaccharide is conjugated to d-Ala(8) GLP-1 using a tetraethylene glycol linker.


METHODS
We assessed GLP-1 receptor binding, cAMP generation and insulin secretory activity of the GLP-1 conjugate in vitro. Circulating half-life, glucose homeostatic and subchronic therapeutic effectiveness were then examined in vivo.


RESULTS
The half-life of the GLP-1 conjugate in mice was ∼11 h. In vitro insulin secretion from clonal β cells and islets was increased (p < 0.001) by the conjugate. The conjugate had half maximum effective concentration values of 1.3 × 10(-7) and 9.9 × 10(-8)  M for displacement of (125) I-GLP-1 in competitive GLP-1 receptor binding and cAMP generation, respectively. Glucose tolerance in normal mice, immediately and 4 h after conjugate injection, resulted in significant (p < 0.001) improvements in blood glucose. These effects persisted for >48 h after administration. Daily treatment (21 days) of high-fat-fed and ob/ob mice with 25 nmol/kg conjugate resulted in significant improvement in glucose tolerance (p < 0.001) and reductions in glycated haemoglobin (HbA1c; p < 0.01) equivalent to or better than with exenatide or liraglutide. Treatment of C57BL/KsJ db/db mice for 15 days with 100 nmol/kg conjugate significantly (p < 0.001) reduced glucose and raised plasma insulin. Oral glucose tolerance was significantly (p < 0.001) improved and both 24-h glucose profile (p < 0.001) and HbA1c levels (p < 0.001) were reduced. Islet size (p < 0.001) and pancreatic insulin content were increased without change of islet cell proliferation or apoptosis.


CONCLUSIONS
These data show that d-Ala(8) GLP-1(Lys(37) ) pentasaccharide exerts significant antidiabetic actions and has a projected pharmacokinetic/pharmacodynamic profile that merits further evaluation in humans for a possible once-weekly dosing regimen.
SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK.|Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, UK.
S
S
Patterson
MSD, Oss, The Netherlands.
M
M
de Kort
SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK.
N
N
Irwin
SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK.
R C
RC
Moffett
MSD, Oss, The Netherlands.
W H A
WH
Dokter
MSD, Oss, The Netherlands.
E S
ES
Bos
MSD, Oss, The Netherlands.
A M M
AM
Miltenburg
SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK.
P R
PR
Flatt
D000818:Animals; D000990:Antithrombin III / Q000378:metabolism*; D000991:Antithrombins / Q000378:metabolism*; D001786:Blood Glucose / Q000187:drug effects; D002373:Cyclic AMP Receptor Protein / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000188:drug therapy*; D059305:Diet, High-Fat; D000077270:Exenatide; D052216:Glucagon-Like Peptide 1 / Q000031:analogs & derivatives* / Q000494:pharmacology; D000067757:Glucagon-Like Peptide-1 Receptor / Q000187:drug effects; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000187:drug effects; D006207:Half-Life; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000097:blood / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000254:growth & development / Q000378:metabolism; D000069450:Liraglutide / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009844:Oligosaccharides; D010179:Pancreas / Q000378:metabolism; D010455:Peptides / Q000494:pharmacology; D014688:Venoms / Q000494:pharmacology
D000990:Antithrombin III; D000991:Antithrombins; D001786:Blood Glucose; D002373:Cyclic AMP Receptor Protein; D000077270:Exenatide; D052216:Glucagon-Like Peptide 1; D000067757:Glucagon-Like Peptide-1 Receptor; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D007328:Insulin; D000069450:Liraglutide; D009844:Oligosaccharides; D010455:Peptides; D014688:Venoms; C558406:HbA(1c) protein, mouse; C000606660:d-Ala(8) GLP-1(Lys(37))pentasaccharide
ATIII; GLP-1; glucagon-like peptide-1; glucose homeostasis; insulin secretion; liraglutide; pentasaccharide