Glucagon-like-peptide-1 (7-36) amide improves glucose sensitivity in beta-cells of NOD mice.
The effect of the insulinotropic gut hormone glucagon-like-peptide-1 (GLP-1) was studied on the residual insulin capacity of prediabetic nonobese diabetic (NOD) mice, a model of insulin-dependent diabetes mellitus (type 1). This was done using isolated pancreas perfusion and dynamic islet perifusion. Prediabetes was defined by insulitis and fasting normoglycemia. Insulitis occurred in 100% of NOD mice beyond the age of 12 weeks. K values in the intravenous glucose tolerance test were reduced in 20-week-old NOD mice compared with age matched non-diabetes-prone NOR (nonobese resistant) mice (2.4 +/- 1.1 vs 3.8 +/- 1.5% min-1, P < 0.05). Prediabetic NOD pancreases were characterized by a complete loss of the glucose-induced first-phase insulin release. In perifused NOD islets GLP-1, at concentrations already effective in normal islets, left the insulin release unaltered. However, a significant rise of glucose-dependent insulin secretion occurred for GLP-1 concentrations > 0.1 nM. This was obtained with both techniques, dynamic islet perifusion and isolated pancreas perfusion, indicating a direct effect of GLP-1 on the beta-cell. Analysis of glucose-insulin dose-response curves revealed a marked improvement of glucose sensitivity of the NOD endocrine pancreas in the presence of GLP-1 (half-maximal insulin output without GLP-1 15.2 mM and with GLP-1 9.4 mM, P < 0.002). We conclude that GLP-1 can successfully reverse the glucose sensing defect of islets affected by insulitis.
Linn
T
T
Medical Clinic III and Polyclinic, Justus Liebig University, Giessen, Germany.
Schneider
K
K
Göke
B
B
Federlin
K
K
D000818:Animals; D002478:Cells, Cultured; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D005934:Glucagon / Q000494:pharmacology; D052216:Glucagon-Like Peptide 1; D004763:Glucagon-Like Peptides; D005947:Glucose / Q000494:pharmacology*; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D051379:Mice; D016688:Mice, Inbred NOD; D008817:Mice, Mutant Strains; D010179:Pancreas; D010446:Peptide Fragments / Q000494:pharmacology*; D013997:Time Factors
D007328:Insulin; D010446:Peptide Fragments; C055453:glucagon-like peptide 1 (7-36)amide; D004763:Glucagon-Like Peptides; D052216:Glucagon-Like Peptide 1; D005934:Glucagon; D005947:Glucose