Incretins - intestinal hormones affecting not only insulin secretion

The cells of the small intestine produce two hormones belonging to the incretin system – glucagon-like peptide-1 (GLP-1) and gastric

inhibitory polypeptide (GIP). Their secretion increases mainly postprandially. Reduced postprandial increase in GLP-1 and reduced sensitivity

of pancreatic beta cells to GLP-1 and GIP effects have been demonstrated in type 2 diabetics compared to non-diabetic individuals.

In type 2 diabetes mellitus, the enzyme dipeptidyl peptidase-4 (DPP-4) known to rapidly degrade incretins also contributes to the

insufficient effect of incretins even with high glucose levels. Incretins result not only in increased insulin secretion from the secretory

granules of pancreatic beta cells when blood glucose is increased, but also in postprandial suppression of glucagon secretion. They also

possess numerous other „non-glycemic“ effects. Some of them slow down gastric emptying and, through their central effect, accelerate

the sensation of saturation and reduce the feeling of hunger in the central nervous system, reduce systolic blood pressure and, in experiments,

interfere with degenerative processes in Alzheimer‘s disease or osteopenia.

pressure.

Keywords: glucagon-like peptide-1, gastric inhibitory polypeptide, non-glycemic effects, weight reduction, reduction in systolic blood