Incretinhormonit

Incretinhormonit, also known as incretin hormones, are a group of gastrointestinal hormones that are secreted in response to the presence of food in the digestive tract. The primary incretin hormones are glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), formerly known as gastric inhibitory polypeptide. These hormones play a crucial role in regulating glucose homeostasis, particularly after a meal.

When carbohydrates and fats are ingested, the intestinal cells release incretins. GLP-1 is primarily produced by L-cells in the distal small intestine and colon, while GIP is synthesized by K-cells in the duodenum and proximal jejunum. Incretins enhance insulin secretion from pancreatic beta cells in a glucose-dependent manner, meaning they stimulate insulin release only when blood glucose levels are elevated. This action helps to lower blood glucose levels after eating. Additionally, incretins suppress glucagon secretion from pancreatic alpha cells, further contributing to glucose control.

Beyond their effects on insulin and glucagon, incretins have other physiological actions. GLP-1, for instance, slows gastric emptying, which helps to reduce the rate at which glucose enters the bloodstream. It also promotes satiety, potentially influencing appetite and food intake. GIP's effects on gastric emptying are less pronounced than GLP-1's, but it also contributes to insulin secretion and has some roles in fat metabolism.

The incretin system is an important component of the body's response to food intake. Due to their beneficial effects on glucose control, incretin-based therapies have been developed for the management of type 2 diabetes. These therapies include GLP-1 receptor agonists, which mimic the action of GLP-1, and dipeptidyl peptidase-4 (DPP-4) inhibitors, which prevent the breakdown of endogenous incretins.