Effects of glucagon and pentagastrin on glibenclamide-induced insulin release

It was recently reported that administration of sulphonylureas may lead to a stimulation of the release of glucagon and a gastrin-like peptide. These peptides may then eventually influence the insulin releasing action of the sulphonylureas. Therefore, the effects of glucagon and pentagastrin on basal and glibenclamide-induced insulin secretion were studied. It was found that at a dose of 4.25 nmol/kg the two peptides induced a significant stimulation of basal insulin secretion. However, pentagastrin at the dose of 4.25 nmol/kg did not influence the insulin release induced by glibenclamide, whereas an equimolar dose of glucagon potentiated the insulin secretory response to this sulphonylurea drug by about 40%. Glucagon in contrast to pentagastrin thus positively modulates the insulin secretory pathway stimulated by the sulphonylurea drug glibenclamide.