Degradation, receptor binding, insulin secreting and antihyperglycaemic actions of palmitate-derivatised native and Ala8-substituted GLP-1 analogues

B.D. Green, V.A. Gault, M.H. Mooney, N. Irwin, P. Harriott, B. Greer, C.J. Bailey, F.P.M. O'Harte, P.R. Flatt

Research output: Contribution to journalArticlepeer-review

Abstract

The hormone glucagon-like peptide-1(7-36)amide (GLP-1) is released in response to ingested nutrients and acts to promote glucose-dependent insulin secretion ensuring efficient postprandial glucose homeostasis. Unfortunately, the beneficial actions of GLP-1 which give this hormone many of the desirable properties of an antidiabetic drug are short lived due to degradation by dipeptidylpeptidase IV (DPP IV) and rapid clearance by renal filtration. In this study we have attempted to extend GLP-1 action through the attachment of palmitoyl moieties to the E-amino group in the side chain of the LyS26 residue and to combine this modification with substitutions of the Ala 8 residue, namely Val or amino-butyric acid (Abu). In contrast to native GLP-1, which was rapidly degraded, [Lys(pal) 26]GLP-1, [Abu8,Lys(pal)26]GLP-1 and [Val8,Lys-(pal)26]GLP-1 all exhibited profound stability during 12 h incubations with DPP IV and human plasma. Receptor binding affinity and the ability to increase cyclic AMP in the clonal β-cell line BRIN-BD11 were decreased by 86- to 167-fold and 15- to 62-fold, respectively compared with native GLP-1. However, insulin secretory potency tested using BRIN-BD11 cells was similar, or in the case of [Val8,Lys(pal)26]GLP-1 enhanced. Furthermore, when administered in vivo together with glucose to diabetic (ob/ob) mice, [Lys(pal)26]GLP-1, [Abu8,Lys(pal) 26]GLP-1 and [Val8,Lys(pal) 26]GLP-1 did not demonstrate acute glucose-lowering or insulinotropic activity as observed with native GLP-1. These studies support the potential usefulness of fatty acid linked analogues of GLP-1 but indicate the importance of chain length for peptide kinetics and bioavailability. Copyright © by Walter de Gruyter.

Original languageEnglish
Pages (from-to)169-177
Number of pages9
JournalBiological Chemistry
Volume385
Issue number2
DOIs
Publication statusPublished - Feb 2004

Keywords

  • DPP IV
  • GLP-1 analogues
  • insulin secretion
  • palmitate

Fingerprint

Dive into the research topics of 'Degradation, receptor binding, insulin secreting and antihyperglycaemic actions of palmitate-derivatised native and Ala8-substituted GLP-1 analogues'. Together they form a unique fingerprint.

Cite this