What is the mechanism of action for DPP4 inhibitors (gliptins)?

DPP4 inhibitors, also known as gliptins, primarily function by preventing the breakdown of incretin hormones, specifically GLP-1 (glucagon-like peptide-1) and GIP (gastric inhibitory polypeptide). Incretins are hormones released by the intestine in response to food intake, and they play a crucial role in regulating glucose metabolism. By inhibiting the enzyme dipeptidyl peptidase-4 (DPP-4), these medications enhance the levels and prolong the action of incretins in the bloodstream.

This action leads to several beneficial effects on glucose homeostasis. For instance, increased GLP-1 levels stimulate insulin secretion from the pancreatic beta cells in a glucose-dependent manner, reduce glucagon secretion from the alpha cells, and slow gastric emptying, all of which work together to lower blood glucose levels without causing significant risk of hypoglycemia. The inhibition of DPP-4 ensures that these incretin hormones remain active longer and can exert their effects more effectively.

The other response options—such as increasing glucose production, stimulating insulin release independent of glucose levels, and inhibiting glucagon secretion—may occur as downstream effects of incretin action but are not the primary mechanism by which D