In conclusion, this analysis has identified the spectrum of peptidesproduced by human and mouse islets in health and metabolic disease,including post-translational modifications and exact peptide sequences.While we could detect active GLP-1 in both human and mouse islets,levels were 100–1000 fold lower than glucagon, suggesting thatthe activity of glucagon on beta cell GLP1R would overcome any effectof local GLP-1 production. This evidence concerns the gene GLP1R and metabolic disease.